US20080132996A1 - Intravascular folded tubular endoprosthesis - Google Patents

Abstract

A bifurcated or straight intravascular folded tubular member is deliverable percutaneously or by small cutdown to the site of a vascular lesion. Its inserted state has a smaller nondeployed diameter and a shorter nondeployed length. The intravascular tubular member has a folded tubular section that is unfolded following insertion into the blood vessel. The length of the intravascular folded tubular member is sized in situ to the length of the vessel lesion without error associated with diagnostic estimation of lesion length. The folded tubular member is self-expandable or balloon-expandable to a larger deployed diameter following delivery to the lesion site. An attachment anchor can be positioned at the inlet or outlet ends of the intravascular folded tubular member to prevent leakage between the tubular member and the native vessel lumen and to prevent migration of the tubular member. The attachment anchor has a short axial length to provide a more focal line of attachment to the vessel wall. Such attachment is valuable in attaching to a short aortic neck in the treatment of abdominal aortic aneurysm. The attachment anchor can have barbs which are held in a protected conformation during insertion of the tubular member and are released upon deployment of the attachment anchor. The intravascular tubular member can be formed of woven multifilament polymeric strands with metallic strands interwoven along with them. Double weaving is incorporated to prevent leakage at crossover points.

Description

BACKGROUND OF THE INVENTION
• 1. Field of Invention
• The present invention relates to a vascular implant that is implanted into an artery for repair or bypass of arterial injury. The vascular implant includes a stent-graft that is delivered intraluminally into an artery for repair of a vascular lesion and more specifically for repair of abdominal aortic aneurysm. The vascular implant further includes an attachment means that provides attachment of a stent-graft to a vessel wall.
• 2. Description of Prior Art
• An abdominal aortic aneurysm is an outpouching of the wall of the aorta that can continue to expand over time possibly leading to rupture and mortality. The outpouched wall is generally filled with thrombus except for a generally tortuous pathway for blood flow through an opening in the thrombus. This thrombus can become organized over time as fibroblasts and other cell types infiltrate and form a more organized matrix material containing collagen and other tissue. Typically such aneurysms occur below or caudal to the renal arteries or veins and can extend distally into the right or left common iliac arteries or further distally into the right or left femoral arteries. The right renal vein which crosses over the ventral surface of the aorta can provide some support to the ventral surface of the aorta an help resist aortic distention. Aortic distention can occur very abruptly just distal to the renal vessels reaching a diameter of six centimeters or greater and causing the onset of accompanying symptoms and requiring repair. Generally the blood flow pathway through the thrombus does not follow these abrupt changes found in the vessel wall but rather continues on in a more direct albeit tortuous path through the thrombus found in the aneurysmal aorta. The abdominal aortic aneurysm can sometimes have a proximal neck or region where the aortic diameter appears to be of normal diameter. This proximal neck region is sometimes found just caudal to the renal vessels. The abdominal aortic aneurysm can sometimes also have a distal neck region located just proximal to the aorto-iliac bifurcation. In this minority of patients the abdominal aortic aneurysm does not extend to the iliac arteries or further distally. Aortic distention in the majority of patients can extend into one or both of the iliac or femoral arteries; repair of this abdominal aortic aneurysm can involve treatment of the iliac and femoral arteries as well. The common iliac artery divides to form the external and internal iliac arteries. The internal iliac artery (also called the hypogastric artery) is important in providing a supply or blood to the pelvic region, genital organs, and other areas and is most often not aneurysmal. The external iliac artery is commonly involved in the aneurysm and extends distally along an oftentimes very tortuous path to form the common femoral artery.
• Surgical repair of an abdominal aortic aneurysm is an extensive procedure associated with a high incidence of morbidity and mortality and requiring many days of hospital stay. Older patients are often not capable of withstanding the trauma associated with this surgery. Repair of abdominal aortic aneurysm intraluminally through access from the common femoral artery can provide the patient with an alternate method of treatment for abdominal aortic aneurysm without the accompanying surgical trauma and long hospital stay. Placement of an intraluminal stent-graft can be performed by an interventionalist using a minimal surgical cutdown to an ipsilateral common femoral artery for access of the device to the arterial system of the body. Generally an additional access site is placed percutaneously in the contralateral common femoral artery. It is often preferred to place at least one more access site cranial to the abdominal aortic aneurysm generally through an axillary artery or other artery of the arm. Spiral computed tomography, duel-plane angiography, intravascular ultrasound, magnetic resonance imaging, and fluoroscopy provide some of the diagnostic techniques used to determine the position, diameter, and length of the aneurysm such that an appropriate intraluminal prosthesis can be selected for intraluminal implantation. Placement of the intraluminal stent-graft requires that a leak tight seal be made between the stent-graft and the aorta and between the stent-graft and each of the iliac or femoral arteries if they are involved in the aneurysm. Failure to provide such a leak tight seal will allow blood flow at arterial pressure to access the space between the stent-graft and the outpouched aorta. Continued exposure to arterial blood pressure can result in further expansion of the aneurysmal sac and could lead to sac rupture. Several intraluminal stent-grafts have been described for use in treatment of abdominal aortic aneurysms.
• Barone describes in U.S. Pat. No. 5,578,072 an apparatus for repairing an abdominal aortic aneurysm. He describes a one-piece bifurcated aortic graft having a balloon expandable stent at one end to secure main trunk of the stent-graft to the aorta caudal to the renal arteries. The one-piece aortic graft has additional expandable stents positioned at the end of each leg of the bifurcated graft to secure the stent-graft to the iliac arteries. This design requires that the length of the main trunk and length of each limb be established prior to implantation using the diagnostic techniques described earlier. Due to the tortuous nature of the blood flow pathway, it is impossible to properly size the length of the graft using these diagnostic techniques prior to implatation. If the stent-graft is sized too short, then a portion of the aneurysm may be left unprotected. If the stent-graft is sized too long for example, then the blood flow to one or both of the internal iliac arteries may be compromised. The method of securing the main trunk of the stent-graft to the aorta caudal to the renal arteries described by Barone is also inadequate in many situations. A balloon expandable stent placed caudal to the renal vessels will very often be located within thrombus and will not have the strength or stability of the aortic vessel wall to support the stent or the stent-graft from migration caudally. Barone teaches that a securing means that is expanded outwardly over an axial length will hold the cranial end of the main trunk in position near the renal vessels. Barone also does not describe any means to prevent the stent-graft from being kinked or crushed as it travels through the thrombus laden blood flow pathway within the aortic aneurysm. Forces imposed upon the stent-graft due to the surrounding thrombus or thrombus organization could easily cause the stent-graft of Barone to become kinked or stenotic thereby impairing its performance. Barone discusses the need to place a stent proximal to the renal arteries for the case that the abdominal aortic aneurysm extends through the aortic region containing the renal arteries. He does not provide a suitable stent-graft for treating infrarenal aortic aneurysm with abrupt wall distension just distal to the renal vessels.
• Parodi describes in U.S. Pat. No. 5,591,229 stent-graft devices that are similar to those described by Barone in the above patent. Additionally, Parodi describes a stent-graft for treatment of an abdominal aortic aneurysm that does not extend into the iliac region. This straight tubular stent-graft has a balloon expandable stent positioned at its cranial end for placement into the proximal neck of the aorta distal to the renal vessels. A balloon expandable malleable wire is placed at the distal end of the stent-graft to provide contact of the stent-graft with the aortic wall in the distal neck of the aorta. This stent-graft has a similar problem associated with estimating the graft length due to the tortuosity associated with the blood flow pathway through the thrombus laden aortic aneurysm. The other problem sited with the device described by Barone are similarly shared by the Parodi device.
• Chuter describes in U.S. Pat. No. 5,693,084 a one-piece bifurcated stent-graft for treatment of abdominal aortic aneurysm having self expanding springs positioned at the proximal end of the main body and at the distal ends of each limb of the graft. The springs expand radially upon release to conform the ends of the stent-graft to the lumen of the aorta. This stent-graft suffers the same problem described for Barone in determining the length of the stent-graft prior to implant. Further, the stent-graft material is not supported throughout the entire stent-graft length thereby providing ample opportunity for stent-graft kinking and deformation within the aneurysm. Chuter has positioned six barbs that extend outward from the self expanding spring on the proximal end of the stent-graft. Due to the geometry of the springs, the positioning of the barbs into aortic wall rather than into the thrombus contained within the aneurysmal wall is not very precise. This can lead to stent-graft migration after a period of time post implant. Other problems associated with the Barone device similarly apply to the Chuter device.
• McDonald describes in U.S. Pat. No. 5,676,697 a two-piece component bifurcated intraluminal stent-graft for treatment of abdominal aortic aneurysm. The first stent-graft component is a flexible tubular member with a side cut near the middle of the tubular member that opens up via a self expanding stent to form a waist region that is seated in the aorto-iliac bifurcation region. Two legs of the first stent-graft component are seated into each iliac artery using stents attached to the distal end of each leg. A second stent-graft component is introduced through one leg of the first component and allowed to self expand in the main trunk of the aorta and form a seal with the waist of the first component. The proximal end of the second component extends proximally within the aorta and makes a seal as it expands outwardly against the flow lumen. This device would have difficulty with positioning the proximal end of the second component within the proximal neck of the aorta. Extreme tortuosity found in the flow lumen of the aortic aneurysm would not allow this device to conform to its shape and would not allow a tight seal to be formed between the proximal end of the second component and the aorta. Difficulty in determining the appropriate length for each of the two components would limit the usefulness of this device.
• Glastra describes in U.S. Pat. No. 5,632,763 a bifurcated component stent-graft assembly for treatment of abdominal aortic aneurysm. The assembly consists of a base stent-graft that is introduced into the main trunk of the aorta from an intraluminal approach. The base stent-graft has a generally cylindrical shape with a conical region located at the distal end. Two secondary cylindrical stents are introduced through two branching arteries, one in each leg and are seated in the conical region of the base stent-graft. This assembly has several potential problems associated with it. Determining the appropriate length of the base stent-graft and each of the secondary stent-grafts cannot be accurately performed considering that all of the arteries involved can be very tortuous and difficult to estimate in length. The seal that is required at the junction of the main to the secondary stent-grafts may have a tendency for leakage due to the geometry of that junction. Glastra describes two cylindrically shaped secondary stent-grafts that are placed adjacent to each other and are required to expand out and seal against a larger cylindrical base stent-graft; this seal would be difficult to form and maintain. Glastra does not address specific means for attachment of the proximal end of the base stent-graft to the aorta.
• Marcade describes in U.S. Pat. No. 5,683,449 a modular system for forming a bifurcated stent-graft for use in treating abdominal aortic aneurysm. The system includes a number of components that are delivered intraluminally to the site of the aneurysm and brought into contact with each other within the aneurysmal space. The primary graft member has a proximal stent at one end and has an decreasing diameter as the stent-graft extends towards its distal end. The base member has a Y-shaped structure with a proximal end that contacts the distal end of the primary graft member. The base member also forms two branches on its distal end, each branch being brought into contact with a tubular graft member that extends into an iliac artery. This modular system still requires that each individual component be sized for length and diameter in order to fit the vast differences found between abdominal aortic aneurysm patients. Each junction between individual components is also a site for potential leakage of blood into the space between the stent-graft and the native arterial conduit. Marcade shows approximately five barbs positioned on the proximal stent. Due to the geometry of the stent it is not possible to obtain precise positioning of the barbs into the aortic wall tissue to ensure long term anchoring that would prevent stent-graft migration and maintain an adequate leak tight seal.
• Vorwerk describes in U.S. Pat. No. 5,562,724 describes a component bifurcated device for treating abdominal aortic aneurysm consisting of a main body and two tubular stent-grafts. The main body has an open proximal end and a distal bag-shaped end with two outlet openings formed in it. Two tubular stent-graft legs can be introduced through the iliac arteries of the patient and attached to the two outlet openings of the main body. Sizing the appropriate length of the main body in addition to the two stent-graft legs is difficult due to the tortuosity found in the blood flow pathway of the aorta and iliac arteries. Leakage at the attachment site of the stent-graft legs to the main body also is a major concern.
• Palmaz describes in U.S. Pat. No. 5,683,453 and Marin in U.S. Pat. No. 5,507,769 two tubular stent-grafts that travel in parallel from the infrarenal aortic neck to each iliac artery. Each stent-graft has a stent positioned at each end of the tube to form a seal with the native artery. This system would also have difficulty in determining the appropriate length of the stent-graft due to vessel tortuosity. In addition, this system requires that the two proximal stents deform against each other and with the proximal neck of the aorta to form a leak tight seal; it is not likely that an appropriate seal or attachment to the proximal aortic neck would be made. Extending a plurality of stent tubular members further within the length of stent-graft create a stent-graft that is too stiff to pass through a tortuous iliac artery to reach the site of the abdominal aortic aneurysm.
• Egoda describes in U.S. Pat. No. 5,591,228 a method of introducing a bifurcated stent-graft for abdominal aortic aneurysm treatment using three access points into the arterial vasculature. As with other intraluminal stent-graft procedures, two access sites involve the common femoral arteries. Egoda describes a third access site made in the left subclavian artery through which the stent-graft can be introduced. This method may allow better control over both ends of the stent-graft during implantation. The length of the stent-graft must still be determined prior to implant and estimation of the length of the blood flow pathway is difficult to determine using standard diagnostic equipment due to the tortuosity of the vessels involved in the aneurysmal dilation.
• A one-piece endovascular graft is described by Piplani in U.S. Pat. No. 5,824,039 for treating a bifurcated abdominal aortic aneurysm lesion. This device has springs located at inlet and outlet ends to hold the graft in place. The springs also have barbs attached. The springs have a large zig zag appearance similar to other prior art attachment means and the barbs are not well protected from inappropriate snagging prior to deployment of the endovascular graft.
• Modular intraluminal prosthesis are described by Lauterjung in U.S. Pat. No. 5,824,036 and by Fogarty in U.S. Pat. No. 5,824,037. Lauterjung describes a composite system using a magnetic tipped guidewire to assist in the assembly of the prosthesis and employs a stent at the ends of the prosthesis and elsewhere. Fogarty describes a self-expanding or resilient frame with a plastically deformable liner over the frame limiting the resilient expansion. Each of these two composite or modular systems shares similar problems to the composite systems described earlier, including the potential for leakage at the junction sites as well as leakage at the junction of the prosthesis with the vessel lumen.
SUMMARY OF THE INVENTION
• The present vascular implant overcomes the disadvantages of prior art stent-grafts, attachment means, and vascular tubular members used for endoprosthetic aortic or arterial aneruysmal repair, or for arterial bypass or other arterial or venous reconstruction. The vascular tubular member of the present invention includes a vascular tubular member that can be intravascularly delivered to the site of vessel injury such as an aortic aneurysm where it is deployed in a manner that will exclude the vessel injury or aneurysm. This intravascular tubular member conveys blood flow from a proximal arterial region that is located proximal to an arterial lesion or aneurysm to one or more distal arterial vessels. One embodiment of the present invention is an intravascular tubular member having a folded tubular section that allows the length of the graft to be adjusted during the time of deployment of the intravascular tubular member. This intravascular tubular member allows the physician to deploy the exact correct length of tubular member for each individual patient and allows the intravascular tubular member to fit different patients that require intravascular tubular members of different lengths. The intravascular tubular member further can have a proximal attachment anchor positioned at its proximal end that allows the proximal end to be positioned accurately in the aortic wall tissue adjacent and distal to the renal arteries. The attachment anchor of the present invention is an attachment anchor that does not undergo significant length change during deployment thereby allowing the position of the attachment anchor within the aortic aneurysm to be accurately determined. The intravascular tubular member can also be anchored to the aorta proximal to the renal vessels for the condition that the aortic aneurysm is abruptly distended adjacent and distal to the renal arteries. The attachment anchor can include barbs to more firmly anchor the intravascular tubular member to the vessel wall. The intravascular tubular member can also include a distal attachment anchor to anchor the distal end of the intravascular tubular member to one or more distal vessels.
• The structure of the vascular tubular member includes a woven structure formed from either multifilament polymeric strands or a composite of multifilament polymeric strands woven along with metal strands. This structure of the vascular tubular member wall is such that it can be supported in both the axial and circumferential directions with metal strands. The circumferentially oriented metal strands provide anti-kink and anti-crush characteristics to the vascular tubular member. The axially oriented metal strands can provide the vascular tubular member with axial compression resistance and ensure that the folded tubular section is maintained in a straight tubular form. These characteristics will provide the tubular sections of the present invention with a more stable pathway for the intravascular tubular member through the thrombus found within a typical abdominal aortic aneurysm. The one-piece construction of the intravascular tubular member of this invention does not allow for leakage at modular junctions such as that which can occur with prior art component or modular intravascular tubular member systems described earlier. One primary application for the intravascular tubular member of the present invention is in the treatment of abdominal aortic aneurysms. Although the description of the invention in this disclosure is directed toward treatment of abdominal aortic aneurysm, it is understood that the present invention is intended for treatment of other vascular lesions both arterial and venous including vessel bypass, traumatic injury, aneurysmal repair, and other lesions.
• The intravascular tubular member of the present invention can be formed from a single straight tube having a proximal end and a distal end. As the intravascular tubular member is being inserted into the patient, it has a smaller nondeployed diameter and a shorter nondeployed length. After the intravascular tubular member is fully deployed, it has a larger deployed diameter and a longer deployed axial length. The straight intravascular folded tubular member is comprised of three sections, a proximal tubular section that includes a proximal tube with an open inlet end, a folded tubular section which includes a folded tube that is able to extend in axial length, and a distal tubular section that includes a distal tube with an open distal end. The proximal, folded, and distal sections are of a length that allows ease of insertion and implantation of the intravascular folded tubular member to vascular application. Alternately, the distal section can be very short and may only include the outlet end of the folded section. In the folded tubular section the folded tube is folded back and forth upon itself generating two circumferential fold lines and forming the folded tubular section of the intravascular folded tubular member. In the folded tubular section a portion of the outer surface of the intravascular folded tubular member is in direct contact with another portion of the outer surface, and a portion of the inner surface is in direct contact with another portion of the inner surface of the intravascular folded tubular member. The nondeployed axial length of the intravascular folded tubular member is shorter than the deployed axial length; the folded tubular section length will shorten as the deployed axial length of the intravascular folded tubular member gets longer. The folded tubular section is positioned distal to the proximal tubular section which can have a proximal attachment anchor attached at the proximal end. Distal to the folded tubular section is a distal tubular section that can have a distal attachment anchor attached at or near the distal end.
• The intravascular folded tubular member can be delivered intraluminally by compressing the intravascular folded tubular member radially to form a compressed conformation that can be delivered to the abdominal aorta or other vessel through a sheath or other delivery means placed in a common femoral artery. Upon delivery of the intravascular folded tubular member into the aorta, the intravascular folded tubular member expands to its deployed diameter. For a self-expanding intravascular folded tubular member the deployed diameter is between the nondeployed diameter and an equilibrium diameter that the intravascular folded tubular member would attain if fully deployed without a restricting force applied from the vessel with which it is in contact. The deployed diameter is generally approximately equal to the diameter of the native vessel that is being repaired. The intravascular folded tubular member can also be expanded by a catheter containing a mechanical expansion means such as a balloon. A proximal attachment anchor can be deployed to form an attachment that seals the proximal end of the intravascular folded tubular member to the aortic wall adjacent and distal to the renal vessels. The proximal attachment anchor does not undergo a significant axial length change during its deployment and as a result can be placed accurately in a position adjacent to the renal vessels for a more reliable attachment to the aortic wall. This reduces any chance for distal migration of the intravascular folded tubular member over time. Attachment of the intravascular folded tubular member to the attachment anchor of the present invention occurs at significantly more sites than is found with other prior art abdominal aortic aneurysm intravascular folded tubular members with zig-zag wire attachment means. The increased number of attachment sites provides a better seal of the attachment anchor and the intravascular folded tubular member to the aortic wall. Barbs can be located on the attachment anchor of the present invention such that they are folded inward during insertion of the device and extend outwards upon deployment of the intravascular folded tubular member.
• The distal end of the intravascular folded tubular member is then positioned at an appropriate location within the abdominal aorta, typically at the site of the distal aortic neck if such a neck exists. It is common to position the distal end of the intravascular folded tubular member into an iliac or femoral artery. As the distal end of the intravascular folded tubular member is being positioned, a portion of the folded tubular section will be unfolded allowing intravascular folded tubular member material contained within the folded tubular section to unfold thereby allowing the intravascular folded tubular member to lengthen to an appropriate deployed axial length that is required to isolate an aneurysm, bypass an artery, or repair in some other way an artery for that individual patient. The length of the tortuous blood flow pathway through the thrombus in the aortic aneurysm can be accurately and appropriately sized in situ when using the intravascular folded tubular member of this invention.
• The material of construction for the wall of the vascular tubular member with a folded tubular section as described previously can be any material that is used in vascular grafts or a combination of materials used in vascular grafts and endovascular stents. Typical vascular graft materials include expanded polytetrafluoroethylene, polyester, silicone, carbon, polyurethanes, biological tissues, silk, composite materials, and others. Some of these materials can be formed into a tube through processing methods that include paste extrusion, electrostatic spinning, spinning without electrostatics, salt leaching, and others. Additionally, the vascular tubular member of this invention which includes the intravascular folded tubular member can be formed from fibers of the materials listed above that have been woven, braided, knitted, or formed into a tubular member. The fibers can preferably be formed of many filaments of a very small diameter and which are wound to form a multifilament fiber or strand Such a multifilament fiber can offer an enhanced sealing capability at the crossover points of a woven or braided fabric vascular tubular member material. It is therefore preferred that a woven or braided tubular member be formed with multifilament yarn or multifilament fibers to reduce blood leakage at crossover points of polymer strand with polymer strand or polymer strand with metallic strand. Typical materials used in the construction of endovascular grafts and stents include Nitinol, stainless steel, tantalum, titanium, platinum, and other metals, metal alloys, and other suitable materials of large elastic modulus. Strands of these and other materials can be interwoven or interbraided with the polymeric materials used in vascular grafts to form a composite wall structure of the present invention.
• A tubular double weaving method can be applied to the construction of the wall of the present vascular tubular member. A construction that involves weaving both polymeric fiber and metallic strands in both longitudinal and circumferential directions can encounter crossover points of one metal strand with another. At such crossover points, leakage or seepage of blood can occur from inside the vascular tubular member to the space outside the vascular tubular member. To reduce or eliminate small pores at the crossover points a tubular double weave is preferred when a metal strand is woven on both the axial and circumferential directions. With this technique a metal strand in one direction is brought out of the surface or the plane of the weave at the crossover point. The woven polymeric material without the metal strand forms a continuous plane of weave beneath the crossover point with good sealing due to the multifilament strands. Thus, leakage cannot occur at metallic strand to metallic strand crossover points due to the elimination of the pores or leakage sites due to the double weaving.
• The attachment anchor that can be positioned at the proximal and distal ends of the intravascular tubular member can be of the self-expanding design or it can require an internal force application to force it outward, such as that provided by a balloon expandable means. The attachment anchor can be used with an intravascular tubular member that has a folded tubular section or it can be used with any other tubular member found in the prior art or that is being used for intravascular treatment of vessel injury. The metal strands that can be interwoven or interbraided into the wall structure of the intravascular tubular member can preferably be of a spring nature such that they self expand from the compressed state to form the deployed diameter; the metal wires can also undergo a plastic deformation as the intravascular tubular member undergoes expansion from its compressed conformation to its deployed diameter upon exposure to forces imposed by a balloon catheter placed within its lumen.
• One preferred embodiment the intravascular folded tubular member of the present invention is a one-piece bifurcated tubular structure or means that is used in the treatment of abdominal aortic aneurysm. The intravascular folded tubular member has a proximal tubular section with a single open inlet end and a bifurcated main trunk that provides passage into two proximal leg tubes. Each proximal leg tube is joined to a folded tubular section, and each folded tubular section is joined to a distal section. The proximal tubular section has a deployed diameter approximately equal to the diameter of the aorta at the aortic proximal neck immediately adjacent and distal to the renal vessels. The two proximal leg tubes can have a diameter approximately equal to the diameter of the iliac artery or femoral artery into which they are to extend. The proximal end of the main trunk can have an attachment anchor attached to provide accurate attachment of the open proximal end within the proximal neck of the aorta. The attachment anchor can include barbs or hooks that provide a more definite attachment of the intravascular folded tubular member to the wall of the aorta to prevent migration, provide a leak-tight seal, and help support the aorta from further distension at that location. The folded tubular sections each have two circumferential fold lines and are folded back and forth in a manner similar to that described earlier for the straight intravascular folded tubular member. Each folded tubular section has a portion of the outer surface of the intravascular folded tubular member in direct contact with a another portion of the outer surface, and it has a portion of the inner surface of the intravascular folded tubular member in direct contact with another portion of the inner surface. The folded tubular sections allow the bifurcated folded tubular member to assume a shorter nondeployed axial length during the delivery of the intravascular folded tubular member than its deployed axial length. Each folded tubular section is attached to a distal tubular section with an open distal end. The open distal end of each distal tubular section can have an attachment anchor attached to form a precise and leak-free attachment to the iliac or femoral arteries.
• A preferred bifurcated intravascular tubular structure or member of the present invention consists of a proximal tubular section or means with a proximal attachment anchor attached to its inlet end, two folded tubular sections attached to the proximal tubular section, two distal tubular sections attached to the two folded tubular sections, and two distal attachment anchor attached to each open distal end. The bifurcated intravascular tubular means is generally introduced into the aneurysmal abdominal aorta intraluminally through a surgical cut down or percutaneous access made into one common femoral artery. A sheath or other introducing means provides suitable access for the intravascular folded tubular member into the blood flow pathway of the aorta. Attachment of the proximal attachment anchor to the aorta is generally made adjacent and distal to the renal vessels. This attachment anchor can be a self-expanding attachment anchor or a balloon expandable attachment anchor. The attachment anchor is preferably short in axial length, has minimal length change upon deployment to allow more accurate placement, and can have barbs extending outward upon deployment to provide better attachment of the intravascular folded tubular member to the vessel wall. The two distal sections of the bifurcated tubular means are generally positioned in the right and left iliac arteries, respectively. The distal ends of the two distal section along with the two distal attachment anchor are positioned at an appropriate location within the iliac or femoral arteries so as to properly exclude the abdominal aortic aneurysm and any additional iliac or femoral aneurysm. As these distal ends are being positioned, the two folded tubular sections will unfold an appropriate amount to allow the deployed axial length of the bifurcated tubular means to be precisely sized to the individual patient. Variations between patients can be accommodated with the folded tubular sections as well as inaccuracies between angiographic length estimations of the aortic aneurysm and the actual length of the aneurysm.
• Distal attachment anchor which are attached to the distal ends of the distal tubular sections can be deployed to form a secure and leak-tight attachment to each iliac artery or femoral artery. The wall structure of the bifurcated folded tubular member is similar to that described for the single straight tube. A woven or braided composite of a polymeric multifilament fiber interwoven or interbraided with a metal fiber can be formed into a one-piece Y-shaped tubular means of the present invention for treatment of abdominal aortic aneurysm with a bifurcated intravascular folded tubular member. Tubular double weaving can be used to reduce leakage sites at crossover points of the metal fibers or strands.
• Another embodiment for the abdominal aortic aneurysm intravascular folded tubular member of the present invention has a proximal section with a bifurcated main trunk having an open inlet end and joined to two proximal leg tubes. In this embodiment only one proximal leg tube is joined to a folded section. The other proximal leg tube has an open distal end that is adapted to accommodate a cylindrically shaped intravascular folded tubular member that can be inserted into the open distal end and sealingly engaged with the proximal leg tube using an engagement means positioned on the cylindrically shaped intravascular folded tubular member. This sealing engagement on one side of the proximal section is similar to the modular systems shown for treatment of abdominal aortic aneurysm in the prior art. This embodiment allows one part of the bifurcated intravascular folded tubular member to be unfolded and extended in length in a manner similar to previous embodiments described in this invention, and the other part of the bifurcated intravascular folded tubular member to be extended by adding additional intravascular folded tubular member segments in a modular fashion as described in the prior art.
• The folded tubular section for the straight or bifurcated intravascular folded tubular member of the present invention has three layers of intravascular folded tubular member wall that lie in direct contact with or in apposition with each other, an outer wall, a center wall, and an inner wall. These three layers extend from a proximal end to a distal end of the folded tubular section. The length of the folded tubular section becomes shorter as the intravascular folded tubular member becomes extended axially during the deployment of the intravascular folded tubular member. In the folded tubular section a portion of the outer surface of the tubular means is in direct contact with the outer surface of another portion of the tubular means, and a portion of the inner surface is in direct contact with another portion of the inner surface. As the folded tubular section becomes unfolded during the deployment it is desirable for the center wall to not wrinkle during the unfolding process. Such wrinkling can occur if the inner and outer wall slide with respect to the center wall rather than unfolding smoothly from the proximal or distal ends of the folded section. One way of significantly reducing or preventing this wrinkling from occurring is to apply a bonding agent or adhesive to the outside surfaces of the folded tubular section. This adhesive is preferably one that resists the shearing motion that is associated with the relative sliding motion that can cause wrinkles to form. The adhesive should also be capable of undergoing fracture due to exposure to extensional or tension stresses that are generated during the desirable unfolding from the proximal or distal ends of the folded section.
• Following deployment of the intravascular folded tubular member of the present invention, it may be desirable to ensure that further unfolding of the folded region does not occur. one or more securing pins or other securing means can be placed through all three walls of the folded tubular section to prevent any further unfolding that may occur after implantation.
• The vascular implant of the present invention includes an attachment anchor that can be attached to the inlet or outlet ends of the intravascular tubular member of this invention, the intravascular folded tubular member of this invention, or of any other prior art tubular means used for intravascular implant. The attachment anchor is formed from a metal tube using machining methods that include mechanical, laser, chemical, electrochemical, or other machining methods to form a pattern of nodes and struts. The nodes and struts are intended to provide independent adjustment of expansion force provided by the attachment anchor uniformly outward against the vessel wall due to its expansion deformation and crush elastic force provided by the attachment anchor against external forces that tend to cause the attachment anchor to form an oval shape associated with crush deformation. The independent adjustment of expansion forces due to deformation in the cylindrical surface of the attachment anchor from the crush force which produces a deformation to a smaller radius of curvature in the radial direction of the attachment anchor such as forming an oval shape, allows the attachment anchor of the present invention to have a shorter axial length for a better focal line attachment to the vessel wall.
• The nodes are formed of at least one hinge and two transition regions. The transition regions are each attached to a strut. A series of struts and nodes are positioned such that the struts are aligned adjacent to each other forming a single folded ring of struts and nodes with a generally cylindrical shape in a nondeployed state with a smaller nondeployed diameter. The attachment anchor of the present invention can be a balloon-expandable or a self-expanding attachment anchor. During expansion of the balloon-expandable attachment anchor, an expanding means such as a balloon dilitation catheter can be inserted along a central axis of the attachment anchor and expanded. The hinges undergo a plastic expansion deformation as the attachment anchor is expanded to a deployed state with a larger deployed diameter. In a deployed state the hinge exerts an outward expansion force through the struts which in turn push against the blood vessel to hold the vessel outwards and hold the intravascular tubular member against the vessel wall without leakage. A self-expandable attachment anchor is held, for example, within a deployment sheath at a smaller nondeployed diameter for delivery into the vasculature. The hinge is deformed elastically in its nondeployed state and exerts an outward force against the sheath. Upon release from the sheath the self-expandable attachment anchor expands outward until it comes into contact with the vessel wall or the intravascular tubular member. The hinge exerts an outward elastic expansion force through the struts which in turn push against the blood vessel to hold the vessel outwards and hold the intravascular tubular member against the vessel wall without leakage.
• Hinges of the present invention have a larger radial dimension than the struts and a thinner width than the struts; the hinge length further having a major role in establishing the outward expansion forces generated by the hinges. The hinge length can be short to focus the expansion deformation of the hinge into a smaller area. For a balloon-expandable attachment anchor the smaller hinge length increases the percentage of metal in the hinge that undergoes a plastic deformation. The result is less rebound of the attachment anchor back towards its nondeployed state following balloon expansion. For a self-expandable attachment anchor the smaller hinge length will generate a greater expansion force for a smaller localized expansion deformation of the hinge. A longer hinge for a self-expandable attachment anchor provides a smaller drop-off of outward expansion force than a smaller hinge length for a specific deployment angle of the attachment anchor. The larger hinge length allows a similar outward force to be applied to the blood vessel wall for a wider range of vessel diameters for the same attachment anchor. For a balloon-expandable attachment anchor an increase in hinge width causes a greater amount of plastic deformation and provides a larger expansion force generated by the hinge than a smaller hinge width. For a self-expandable attachment anchor an increase in hinge width causes a larger outward expansion elastic force to be exerted against the vessel wall. A hinge radial dimension larger than the strut radial dimension produces a larger outward expansion force for both the balloon-expandable or self-expandable attachment anchor. The large hinge radial dimension does not allow the hinge to bend in a radial direction to form an oval such as would like to occur during exposure to a crush deformation.
• The struts of the attachment anchor have a larger width than the hinge width such that the hinges can transfer their outward force through the struts to the vessel wall without allowing any bending of the struts in the cylindrical surface of the attachment anchor. The struts have a small radial dimension in comparison to the hinge radial dimension to allow the struts to deform elastically to a smaller radius of curvature in the radial direction of the attachment anchor upon exposure to a crush deformation. The strut width allows the struts to deform elastically at any prescribed crush force during exposure to a crush deformation. A longer strut length allows a greater percentage of the perimeter of the attachment anchor to be associated with the struts in comparison to the hinges or nodes. The longer struts provide the attachment anchor with an increased flexibility in the radial direction when exposed to a crush deformation. Conversely, a shorter strut provides the attachment anchor with a greater stiffness in the crush deformation mode with other attachment anchor dimensions remaining the same. The greater stiffness associated with an attachment anchor with such a shorter length strut allows the strut to be formed with a thinner radial dimension or smaller width and still have the same flexibility in crush deformation as a longer strut.
• The attachment anchor of the present invention can be formed out of a higher modulus metal that other attachment devices. Other prior art attachment devices cannot be formed of the highest modulus metal because their expansion force cannot be changed without also affecting their crush force. With the present attachment anchor the outward expansion force can be designed independently from the crush force provided by the attachment anchor. The present attachment anchor can be formed such that it is short in axial length in order to provide a more focused line of attachment to the vessel wall. Short stents formed with prior art designs can be designed to provide an appropriate outward expansion force, however this prior art stent would be too stiff or too flexible in a crush deformation and would be without the ability to adjust the crush deformation force with respect to the outward expansion force. The present attachment anchor can be designed to provide both an appropriate expansion force and an appropriate crush force. The hinge of the present attachment anchor can also provide more expansion force than other prior art attachment devices due to the use of higher modulus metal and due to the dimensions chosen for the hinge width, length, and radial dimension. The close efficient packing of the struts parallel to each other provides the present attachment anchor with a large expansion ratio. The short strut length allows the strut width to be minimized while still maintaining an appropriate flexibility in crush deformation further maximizing the expansion ratio provided by the present attachment anchor. The strong expansion force provided by the hinge allows an appropriate expansion force to be generated such that the attachment anchor of this invention with short axial length can provide adequate expansion forces to hold a large vessel such as the aorta outward and prevent leakage between the intravascular tubular member and the vessel wall.
• The vascular tubular member tubular wall structure can be formed from a composite of polymeric and metallic strands that are either woven or braided to provide different characteristics in its axial and circumferential directions. In a weaving process for tubular structures one or more strands have substantially a circumferential direction and another group of strands have generally an axial direction. In a weaving process the substantially circumferential strands generally have a gradual helical wind that is approximately perpendicular to the longitudinal axis of the vascular tubular member but the strands are continuous and actually form a helix. A polymeric strand can be made up of substantially straight filaments to form a straight polymeric strand. This straight polymeric strand can be woven in a circumferential direction forming a straight circumferential polymeric strand, or woven in an axial direction forming a straight axial polymeric strand. The polymeric strand can also undergo a thermal, mechanical, or chemical forming process that can heat set, mechanically set, or chemically deform the polymer filaments or the strand to have local bends, helical spirals, or curves in it. The local bends can be spaced very close together with spacing approximately equal to the diameter of the filament. Alternately, the local bends can be spaced apart further than the diameter of a fiber that is made up of many filaments. This curved polymeric strand will have the characteristic that it can stretch or elongate in its axial direction. This curved polymeric strand can be woven in a circumferential direction forming a curved circumferential polymeric strand, or it can be woven in an axial direction forming a curved axial polymeric strand. The straight or curved polymeric strand could be made from filaments of expanded polytetrafluoroethylene, from filaments of Dacron polyester, polyurethane, or from other suitable polymeric filaments.
• The metallic strands that could be interwoven between the polymeric strands could be formed from a straight metallic strands, fibers, or wire formed from a metal such as Nitinol, stainless steel, titanium, tantalum, or other suitable metal or alloy. The wire can be round in cross section or it can be flat wire with a more rectangular cross section. It is preferable for one embodiment that the wire or metallic strand be of an elastic nature that does not exceed its elastic limit during the deployment of the vascular tubular member of the present invention. The wire in another embodiment could undergo plastic deformation during the deployment of the vascular tubular member. This straight metallic strand can be woven in the circumferential direction forming a straight circumferential metallic strand, or it can be woven in the axial direction forming a straight axial metallic strand. The metallic strand can also undergo a thermal, mechanical, or chemical forming process that can heat set, mechanically set, or chemically set the metallic strand to have local bends, helices, or curves in it. This curved metallic strand will have the characteristic that it can either stretch or compress in its overall axial direction. This curved metallic strand can be woven in a circumferential direction forming a curved circumferential metallic strand, or it can be woven in an axial direction forming a curved axial metallic strand. When woven in an axial direction, the curved wire is held under tension and is therefore held in a straight conformation. Upon release of the metallic strand, it forms the curved shape that was formed into the metallic strand prior to weaving. Circumferentially weaving a curved metallic strand requires additional effort due to the tortuous pathway followed by the strand during the weave.
• The vascular tubular member wall structure of the present invention can include a woven tubular structure consisting of curved and straight, polymeric and metallic strands in the circumferential and axial directions. In one structure straight circumferential polymeric strands and one or more straight circumferential metallic strands are interwoven circumferentially and straight axial polymeric strands are woven axially. This structure is easy to form and has good hoop strength that will resist kinking due to the metallic component. The folded tubular section has good approximation between the inner, center, and outer walls since only the polymeric strands are extending axially allowing the circumferential fold lines to have a very small radius of curvature.
• In another vascular tubular member wall structure additional straight axial metallic strands are interwoven with the straight axial polymeric strands of the structure just presented above. The additional straight axial metallic strands provide the folded tubular section with the characteristic that resists wrinkling in the folded tubular section. A tubular double weave can be used whenever two metal strands form a crossover point. One of the metal strands can be brought out of the plane of the weave prior to the crossover point and reenter the plane of the weave after the crossover point. The weaving plane is thus continuous without one of the metal strands and leakage at that crossover point will not occur. The additional straight axial metallic strands offer axial strength against compressive deformation but can cause the vascular tubular member to become stiff and more difficult to negotiate the tortuous turns of the iliac and femoral arteries.
• In still another vascular tubular member wall structure a curved axial metallic strand is interwoven with straight axial polymeric strands in the vascular tubular member wall structure just presented above instead of straight axial metallic strands. The curved axial metallic strands provide a benefit to the folded tubular section to resist wrinkling during the unfolding process. The curved axial metallic strands also provide the vascular tubular member with good axial support against compressive forces generated by the thrombus and other physiological forces that can be placed upon the vascular tubular member. The curved axial metallic strands can compress elastically and thereby will not provide this vascular tubular member wall structure with good flexibility and will resist vascular tubular member kinking.
• In yet another vascular tubular member wall structure straight circumferential polymeric strands are interwoven with one or more curved circumferential metallic strands in the circumferential direction and straight axial polymeric strands are interwoven with curved axial metallic strands in the axial direction. The curved circumferential metallic strands found in this structure allows the folded tubular section to unfold with greater ease due to their ability to elongate diametrically as, for example, one curved circumferential metallic strand located in an inner or outer wall passes adjacent to another curved circumferential metallic strand located in the center wall. The curves or bends in the curved circumferential metallic strands also allows the vascular tubular member to expand out uniformly to its deployed diameter which can be smaller than the equilibrium diameter of the vascular tubular member and provide uniform contact with the aortic wall.
• In one more vascular tubular member wall structure curved circumferential polymeric strands are interwoven with one or more straight circumferential metallic strands in the circumferential direction and straight axial polymeric strands are interwoven with curved axial metallic strands in the axial direction. The curved circumferential polymeric strands provide an amount of circumferential stretch in the diametric direction. The other components of the weave restrict excessive circumferential stretch. This vascular tubular member structure can also be modified slightly to provide an additional characteristic. Near the proximal end of the tubular means the straight circumferential metallic strands can be eliminated thereby allowing the vascular tubular member to expand to a larger circumference. This circumferential expansion allows the vascular tubular member of the present invention to accommodate a reasonable tolerance in the estimated aortic neck diameter of a few millimeters. Similar circumferential accommodation also applies to the iliac artery.
• Accommodation of the estimated aortic diameter with a vascular tubular member of a fixed non-flexible wall material with a maximum diameter can also be accomplished by ensuring that the vascular tubular member chosen can expand to a slightly larger diameter than the aortic diameter. Any embodiment of vascular tubular member wall structure of this disclosure can provide this characteristic. Any excess graft wall material will result in a wrinkle or fold if the perimeter of the tubular member is slightly larger than the perimeter of the aorta, for example. Provided that this wrinkle or fold is held tightly against the aortic wall by the proximal attachment anchor, leakage at the proximal site will not occur.
• In yet one more vascular tubular member wall structure curved circumferential polymeric strands are interwoven with one or more curved circumferential metallic strands in one direction and the axial direction is the same as the vascular tubular member wall structure just described above. This structure offers the ability to stretch in the circumferential direction to a limited extent controlled by the amount of curvature provided to the circumferential strands. This vascular tubular member wall structure provides good anti-kink characteristics, good axial support against compression, good flexibility, and will accommodate a reasonable tolerance in the aortic neck diameter, and a tolerance on the iliac artery diameter.
• In still one more vascular tubular member wall structure curved circumferential polymeric strands are interwoven with one or more curved circumferential metallic strands in one direction and the axial direction contains curved axial polymeric strands interwoven with curved axial metallic strands. This structure offers the ability to stretch in the circumferential and axial direction to a limited extent controlled by the amount of curvature provided to the circumferential and axial strands, respectively. This structure can extend in each direction throughout the entire tubular means. This vascular tubular member wall structure provides good anti-kink characteristics, good axial support against compression, good flexibility, and will accommodate a reasonable tolerance in the aortic neck diameter, and a tolerance on the iliac artery diameter.
• All of the vascular tubular member wall structures presented in this disclosure can be formed with the axial metallic strands being directed with an augmented amount of helical turn. This is accomplished by taking metallic strand out of the weaving plane, stepping over to a new site that is displaced circumferentially, and inserting the metallic strand back into the plane of the weave. This stepping over process allows the axial metallic strand to assume a helical pathway along the axial direction of the vascular tubular member. This augmented amount of helical turn is in addition to the gradual helical turn naturally found in the axially oriented metallic strands due to their natural desire to orient perpendicular to the generally circumferential strands which also have a slight helical turn since they are wound in a continuous helix. The augmented helical turn of the metallic strands in the generally axial direction provides the vascular tubular member with an ability to bend without kinking even when straight metallic strands are used in the axial direction. Enhanced helical turn in the circumferential direction can also be accomplished by weaving two or more metallic strands into the circumferential weave. This can provide a steeper angel for the helical wind and provide additional axial flexibility without kinking.
• In a preferred embodiment curved polymeric strands are wound in both the circumferential and axial direction to provide the vascular tubular member with a supple feel and good bending characteristics without kinking. For simplicity of manufacturing, one or more straight metallic strands are wound in the circumferential direction. Either curved metallic strands or straight metallic strands with the step over characteristic described above is used in the axial direction to provide the necessary compressive strength as well as provide good flexibility to the vascular tubular member. An entire straight or bifurcated vascular tubular member can be formed from a single contiguous woven material comprised of the polymeric and metallic strands described above. The vascular tubular member is woven without seam in its proximal, folded or distal section. For the bifurcated tubular member this is accomplished by splitting the number of strands that extend axially such that approximately half of those present in the main trunk extend down one proximal leg and half extend down the other proximal leg.
• The vascular tubular member wall structure of the present invention can also be formed from a braiding process wherein straight polymeric and straight metallic strands are braided in a right hand spiral forming straight right spiral polymeric strands and straight right spiral metallic strands. These strands can be made with localized bends or curves in them as described earlier, and these strands can be braided into a right hand spiral to form curved right spiral polymeric strands and curved right spiral metallic strands. Similarly the straight and curved, polymeric and metallic strands can be braided into a left hand spiral.
• In one vascular tubular member wall braided structure a straight right spiral polymeric strand and a straight right spiral metallic strand are interbraided together in one direction and a straight left spiral polymeric strand and a straight left spiral metallic strand are interbraided in the opposite direction. The braiding process provides some ability for this wall structure to accommodate reasonable tolerances in the estimation of the proximal aortic neck diameter in order to provide a good diametric fit between the vascular tubular member and the proximal aortic neck. The presence of the straight and curved metallic strands provides good axial and circumferential strength and stability against compression in the radial or axial direction in comparison to other prior art materials of construction.
• In other vascular tubular member embodiments the braided structure can involve either curved metallic strands or curved polymeric strands. These curved metallic or polymeric strands will provide the vascular tubular member with a greater flexibility due to the ability of these metallic strands to compress as the vascular tubular member is exposed to a tortuous pathway.
• It is understood that the woven and braided vascular tubular member wall structures presented are not intended to be complete and that other combinations of straight and curved, polymeric and metallic strands can be used with weaving or braiding with the associated characteristics and advantages that have been described or taught in this disclosure.
• The bifurcated tubular member used in the treatment of abdominal aortic aneurysm described in this invention can have a proximal attachment anchor attached at the proximal end of the bifurcated main trunk. This attachment anchor provides a circumferential expansion and attachment to the aorta without significant change in axial length. This small axial length change allows this attachment anchor to be placed very near to the renal arteries with precision and reduce the likelihood for distal migration of the vascular tubular member. A greater number of barbs can be placed on the attachment anchor due to the geometry of the attachment anchor which has a short axial length and involves a hinge to supply the outward forces of the attachment anchor. The increased number of barbs will better hold the vascular tubular member to the aorta around the entire circumference.
• The bifurcated folded tubular member of the present invention can also have a proximal attachment anchor that is displaced proximally from the proximal end of the main trunk. The displaced attachment anchor can be joined to the bifurcated main trunk by the metal strands that are woven axially or helically into the vascular tubular member or by the metal strands that are braided into the vascular tubular member. The displaced proximal attachment anchor is intended in one embodiment to provide attachment proximal to the renal arteries in a region of the aorta that is significantly proximal to the aneurysmal region of the aorta. Since many abdominal aortic aneurysms occur adjacent to the renal vessels and generally distal to the renal vessels, it is sometimes necessary to find a proximal attachment site that is proximal to the renal arteries. The displaced proximal attachment anchor will provide this attachment capability and prevent any distal migration of the intravascular tubular member. The small metallic strands that connect the displaced attachment anchor to the main trunk of the intravascular tubular member can cross over a renal artery without causing a significant thrombotic or occlusive effect. The metallic strands are positioned around the circumference to provide the main trunk with support from the attachment anchor along its entire circumference. Only a minimal number of metallic strands extend to the displaced attachment anchor in order to reduce the chances for thrombus formation at the entrances to the renal arteries. The number of strands can range from two to approximately sixteen. An additional proximal attachment anchor may be attached to the open proximal end of the main trunk in addition to the displaced attachment anchor to provide a tight leak-free seal with the aorta. The displaced attachment anchor can have barbs to enhance attachment to the aorta or it can be an attachment anchor without barbs as described earlier. The metallic strands can be attached to selected securing sites of the attachment anchor.
BRIEF DESCRIPTION OF THE DRAWINGS
• Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein:
• FIG. 1A is a sectional view of a vascular tubular member implanted within an abdominal aortic aneurysm;
• FIG. 1B is a sectional view of an intravascular tubular member implanted in a bifurcated abdominal aortic aneurysm;
• FIG. 2A is a sectional view of a straight intravascular folded tubular member in a partially deployed state;
• FIG. 2B is a sectional view of a straight intravascular folded tubular member in a fully deployed state;
• FIG. 2C is a cross sectional view of a straight intravascular folded tubular member near the inlet end in a nondeployed state;
• FIG. 2D is a cross sectional view of a straight intravascular folded tubular member near the outlet end in a nondeployed state;
• FIG. 2E is a sectional view of a straight intravascular folded tubular member in an unfolded state;
• FIG. 3 is an isometric view of a straight intravascular folded tubular member in a nondeployed state with an attachment means at inlet and outlet ends;
• FIG. 4A is a sectional view of a bifurcated intravascular folded tubular member in a partially deployed state;
• FIG. 4B is a sectional view of a bifurcated intravascular folded tubular member in a fully deployed state;
• FIG. 4C is a sectional view of a bifurcated intravascular folded tubular member in a nondeployed state within a delivery sheath near the inlet end;
• FIG. 4D is a sectional view of a bifurcated intravascular folded tubular member in a nondeployed state within a delivery sheath near the outlet ends;
• FIG. 4E is a sectional view of a bifurcated intravascular folded tubular member in a nondeployed state on a balloon dilitation catheter near the inlet end;
• FIG. 4F is a sectional view of a bifurcated folded tubular member in an unfolded state;
• FIG. 5 is a partially sectioned view of a bifurcated folded tubular member in a nondeployed state with attachment means at the inlet and outlet ends;
• FIG. 6 shows a sectional view of a folded tubular section in a nondeployed state with a bonding agent applied;
• FIG. 7A is a schematic sectional view of the folded tubular section in a nondeployed state;
• FIG. 7B is a schematic sectional view of the folded tubular section unfolded from the circle to the point-down triangle;
• FIG. 7C is a schematic sectional view of the folded tubular section unfolded from the square to the point-up triangle;
• FIG. 7D is a schematic sectional view of the folded tubular section unfolded evenly;
• FIG. 7E is a schematic sectional view of the folded tubular section with wrinkling;
• FIG. 8 is a sectional view of a folded tubular section with holding pins;
• FIG. 9A is an isometric view of an attachment anchor with one hinge per node in a nondeployed state;
• FIG. 9B is an isometric view of an attachment anchor with one hinge per node in a deployed state;
• FIG. 9C is an enlarged detailed isometric view of a node of an attachment anchor with one hinge;
• FIG. 9D is a perspective view of an attachment anchor with an oval attachment anchor surface;
• FIG. 10A is an isometric view of an attachment anchor with two hinges per node in a nondeployed state;
• FIG. 10B is an isometric view of an attachment anchor with two hinges per node in a deployed state;
• FIG. 10C is an enlarged detailed isometric view of a node of an attachment anchor with two hinges;
• FIG. 10D is a perspective view of an attachment anchor with nodes and struts in a closed configuration in a nondeployed state;
• FIG. 10E is a perspective view of an attachment anchor with nodes and struts in a closed configuration in a deployed state;
• FIG. 11A is an isometric view of an attachment anchor with barbs in a nondeployed state;
• FIG. 11B is an enlarged view of a portion of an attachment anchor with barbs in a nondeployed state;
• FIG. 11C is an isometric view of an attachment anchor with barbs in a deployed state;
• FIG. 11D is an enlarged view of a portion of an attachment anchor with barbs in a deployed state;
• FIG. 12A is an isometric view of attachment anchors positioned at an inlet end and an outlet end of an intravascular tubular member;
• FIG. 12B is an isometric view of attachment anchors positioned at an inlet end and an outlet end of a straight intravascular folded tubular member;
• FIG. 12C is a partially sectioned view of attachment anchors positioned an inlet and outlet ends of a bifurcated intravascular folded tubular member;
• FIG. 13A is a perspective view of a woven vascular tubular member;
• FIG. 13B is a perspective view of a woven multifilament strand wall structure for a vascular tubular member;
• FIG. 13C is a perspective view of a woven monofilament strand wall structure;
• FIG. 13D is a perspective view of a multifilament strand formed of filaments;
• FIG. 13E is a perspective view of an expanded polytetrafluoroethylene filament;
• FIG. 13F is a perspective view of a straight multifilament strand formed of straight filaments;
• FIG. 13G is a perspective view of a curved multifilament strand formed of curved filaments;
• FIG. 13H is a perspective view of a curved expanded polytetrafluoroethylene filament formed of microfilaments;
• FIG. 13I is a perspective view of a vascular tubular member formed of expanded polytetrafluoroethylene strands;
• FIG. 13J is a perspective view of a wall structure formed of metallic strands woven along with polymeric multifilament strands;
• FIG. 13K is a perspective view of a straight monofilament strand;
• FIG. 13L is a perspective view of a curved monofilament strand;
• FIG. 13M is a perspective view of a woven wall structure of flattened metallic strands;
• FIG. 14 is a representation of a vascular tubular member with a woven wall structure having straight axial metallic, straight axial polymeric, straight circumferential metallic, and straight circumferential polymeric strands;
• FIG. 15 is a perspective view of double weaving at a metal to metal crossover point;
• FIG. 16A is a representation of a vascular tubular member with a woven wall structure having straight axial polymeric, straight circumferential polymeric, and straight circumferential metallic strands;
• FIG. 16B is a representation of a vascular tubular member with a woven wall structure having straight axial polymeric, curved axial metallic, straight circumferential polymeric, and straight circumferential metallic strands;
• FIG. 16C is a representation of a vascular tubular member with a woven wall structure having straight axial polymeric, curved axial metallic, straight circumferential polymeric, and curved circumferential metallic strands;
• FIG. 17A is a representation of a vascular tubular member with a woven wall structure having straight axial polymeric, curved axial metallic, curved circumferential polymeric, and straight circumferential metallic strands;
• FIG. 17B is a representation of a vascular tubular member with a woven wall structure having straight axial polymeric, curved axial metallic, curved circumferential polymeric, and curved circumferential metallic strands;
• FIG. 17C is a representation of a vascular tubular member with a woven wall structure having curved axial polymeric, curved axial metallic, curved circumferential polymeric, and curved circumferential metallic strands;
• FIG. 18A is a representation of a vascular tubular member with a woven wall structure having curved circumferential polymeric, straight circumferential metallic, curved axial polymeric, and straight axial metallic strands having a circumferential step-over;
• FIG. 18B is a representation of a vascular tubular member with a woven wall structure having curved circumferential polymeric, curved axial polymeric, straight circumferential metallic, and curved axial metallic strands with augmented helical turn;
• FIG. 19 is a representation of a vascular tubular member with a braided wall structure having left and right spirals of multifilament polymeric and monofilament metallic strands;
• FIG. 20 is a partially sectioned view of an intravascular tubular member formed of a woven wall structure with multifilament polymeric strands and axially directed metallic strands interwoven and a displaced attachment anchor;
• FIG. 21 is an intravascular folded tubular member formed with a woven wall structure of multifilament polymeric strands interwoven along with monofilament metallic strands;
• FIG. 22 is an intravascular folded tubular member formed with a woven wall structure formed entirely of multifilament polymeric strands;
• FIG. 23 is a bifurcated intravascular folded tubular member formed of a woven wall structure of multifilament polymeric strands interwoven along with monofilament metallic strands and having attachment anchors at the inlet and outlet ends.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• The present invention is a vascular implant intended for use to repair injured arteries or veins of the body. Such injuries can include aneurysms, stenoses, diffuse atherosclerosis, traumatic injury, or other injury that requires vascular repair or bypassing of the vessel. The vascular implant includes a vascular tubular member that conveys blood flow from a region of the repaired blood vessel proximal to the vessel injury to a region distal to the vessel injury. The vascular tubular member is primarily intended to be an intravascular tubular member for intravascular use using percutaneous access to the interior of the vessel or a minimal surgical cutdown to access a blood vessel either proximal or distal to the injured vessel that is to be repaired. The intravascular tubular member is entered into the proximal or distal blood vessel in a smaller diameter nondeployed conformation and is delivered to the site of the vessel injury where it enlarges to a larger diameter providing a passage for blood flow. An embodiment of the present invention is an intravascular folded tubular member that also enlarges in length following delivery to the site of vessel injury. One intravascular repair application that is in particular need of improvement is the repair of aortic aneurysms and most common the repair is one involving the abdominal aorta. The present invention is well suited to provide improvements in treating abdominal aortic aneurysms although it can also be used effectively in the repair of vessels throughout the body. The intravascular tubular member can include an attachment means attached to the proximal end or distal end of the intravascular tubular member to hold the intravascular tubular member firmly into contact with the wall of the injured blood vessel, prevent blood leakage at the proximal end or distal end, and prevent distal migration of the intravascular tubular member. The vascular implant of the present invention includes an attachment means that can be used with other prior art intravascular devices in addition to the intravascular tubular member of the present invention. The vascular tubular member includes not only the intravascular tubular member but also includes a surgical vascular graft that can be implanted surgically for repair of vascular injury. A vascular tubular member can include other tubular members that can have a generally tubular shape and have application in the repair of blood vessels. A woven and braided wall structure is presented that has application to both surgical vascular grafts as well as intravascular tubular members. It is understood that the present invention is not limited to the embodiments presented in this disclosure. The present invention can also be applied to other tubular organs of the body besides blood vessels. Such tubular organs include but are not limited to the intestines, esophagus, trachea, bile ducts, or other ducts of the body.
• FIGS. 1A and 1B show a side and frontal view of abdominalaortic aneurysms5. The abdominalaortic aneurysm5 can be used as an example of an arterial injury that can be treated with one or more embodiments of the present invention. Distension of theabdominal aorta10 often extends from distal to the leftrenal vein15 to the commoniliac artery20, externaliliac artery25, commonfemoral artery30 or to more than one artery. The leftrenal vein15 follows a path anterior to the aorta from theleft kidney35 to theinferior vena cava40. The leftrenal vein15 can provide some support to assist theabdominal aorta10 from further distension proximal to the leftrenal artery45 and rightrenal artery50. A blood flownative lumen53 extends from thesuprarenal aorta55 through the distendedabdominal aorta10, through the aorto-iliac bifurcation57, and into each commoniliac artery20, each externaliliac artery25, and each commonfemoral artery30.Thrombus60 fills the cavity that exists between the blood flownative lumen53 and the abdominalaortic wall70.Lumbar arteries75 located on the posterior side of the aorta and other arteries of the region can be occluded due to the presence ofthrombus60 or may remain patent depending upon the severity of the aneurysm. Each internaliliac artery80 is often patent and should be allowed to remain patent when repairing an abdominalaortic aneurysm5 if possible. An embodiment of thevascular implant82 of the present invention is shown inFIG. 1A. Thevascular implant82 can include avascular tubular member83 that can be placed surgically within the native lumen or thevascular implant82 can be anintravascular tubular member85 that could have a bifurcation and could be placed percutaneously or with minimal surgical cutdown through a distal or other connecting vessel to reach the site of vessel injury as shown inFIG. 1B. InFIG. 1B the intravascular tubular member could have been inserted by a sheath placed in one of the commonfemoral arteries30 and delivered to theabdominal aorta10. Theintravascular tubular member85 can have an attachment means87 attached to it to help provide a seal between theintravascular tubular member85 and thenative lumen53 and help reduce migration of theintravascular tubular member85. Thevascular implant82 can include the attachment means87 which can be used with theintravascular tubular member85 of the present invention or it can be used with other stent-graft devices. Theintravascular tubular member85 can be bifurcated with a bifurcation that extends from a proximalaortic neck90 to each commoniliac artery20, commonfemoral artery30, or other distal artery. Theintravascular tubular member85 can also have other configurations and embodiments which will be explained further in this disclosure.
Folded Tubular Members
• A first embodiment of the present invention (seeFIGS. 2A-2D) is a straight intravascular foldedtubular member95 for repairing an arterial lesion, an aneurysm, or other vascular injury found in a blood vessel. The straight intravascular foldedtubular member95 is intended to provide ablood flow passage100 from a region of the blood vessel proximal to the vascular injury to a region of blood vessel distal to the vascular injury. The preferred method of deploying the straight intravascular foldedtubular member95 is to insert it through a percutaneous access through a sheath as is well known in the industry or with a small surgical cutdown to provide direct access to a blood vessel located either proximal or distal to the vascular injury.
• FIG. 2A shows the straight intravascular foldedtubular member95 in a radially deployed state with a radially deployedinlet end diameter105, a radially deployedoutlet end diameter110, and a straight nondeployedtubular member length115. The straight intravascular foldedtubular member95 has a straight proximaltubular section120, a foldedtubular section125, a distaltubular section130, aninner surface135 and anouter surface140. Theinner surface135 andouter surface140, and intravasculartubular member wall143 each extend continuously from aninlet end145 through the straight proximaltubular section120, through the foldedtubular section125, and through the distaltubular section130 to anoutlet end148 of the foldedtubular section125. The continuous intravasculartubular member wall143 can have attachments between the straight proximaltubular section120 and the foldedtubular section125 and between the foldedtubular section125 and the distaltubular section130 although it is preferred to form the intravasculartubular member wall143 with each of these sections joined contiguously from the same material without attachments between sections. Theinner surface135 of the straight proximaltubular section120 and the distaltubular section130 is a blood flow surface in contact with blood flow. A portion of the inner surface of the foldedtubular section125 is a blood flow surface in contact with blood flow. The straight proximaltubular section120 hasinlet end145 that provides passage for blood flow into the straight proximaltubular section120 and into the straight intravascular foldedtubular member95. The straight proximaltubular section120 has a straight nondeployed proximaltubular section length150. The straight proximaltubular section120 is joined either contiguously or with an attachment to the foldedtubular section125. The foldedtubular section125 is formed from a continuous tube that is folded back and forth upon itself to form three separate walls, a folded tubular sectionouter wall155, a folded tubularsection center wall160, and a folded tubular sectioninner wall165. The folded tubular sectioninner wall165 is joined either contiguously or with attachment to a straight proximaltubular section wall170 to form a continuous wall. The foldedtubular section125 has a proximalcircumferential fold line175 and a distalcircumferential fold line180 and has a nondeployed foldedtubular section length185 extending from the proximalcircumferential fold line175 to the distalcircumferential fold line180. The portion of the intravasculartubular member wall143 that forms the foldedtubular section125 has anupstream end187 and a folded tubular sectiondownstream end188. The straight proximaltubular section wall170 is joined to the folded tubular sectionupstream end187 and the distaltubular section wall190 is joined to the folded tubular sectiondownstream end188. In the foldedtubular section125, a portion of theinner surface135 of the straight intravascular foldedtubular member95 is in apposition with another adjoining portion of theinner surface135. Similarly, in the folded tubular section125 a portion of theouter surface140 is in apposition with another adjoining portion of theouter surface140. The folded tubular sectionouter wall155 is joined either contiguously or with an attachment to a distaltubular section wall190 of the distaltubular section130 to form a continuous wall. The distaltubular section130 has anoutlet end148 to provide passage of blood flow out of the distaltubular section130 and out of the straight intravascular foldedtubular member95. The distaltubular section130 has a nondeployed distaltubular section length200 extending from the foldedtubular section125 to theoutlet end148. The straight intravascular foldedtubular member95 has a straight nondeployedtubular member length115 that extends from theinlet end145 to theoutlet end148. The straight intravascular foldedtubular member95 has ablood flow passage100 which provides passage of blood flow from theinlet end145 to theoutlet end148. The distalcircumferential fold line180 is in contact with theblood flow passage100 such that shear forces acting by the blood onto theinner surface135 will not act to generate separation between the three walls of the foldedtubular section125. The distaltubular section130 has a nondeployed distaltubular section length200 that can provide significant length in accordance with the length requirements for a specific vascular application. Alternately, it is understood that the nondeployed distaltubular section length200 can be very short such that it includes essentially only theoutlet end148 without any significant length.
• FIG. 2B shows the straight intravascular foldedtubular member95 in a fully deployed state or in an implanted state with a radially deployedinlet end diameter105, a radially deployedoutlet end diameter110, and a straight deployedtubular member length205. Theinlet end145 and outlet end148 have been extended in axial position with respect to each other. To accomplish the longer straight deployedtubular member length205 the foldedtubular section125 has unfolded such that its deployed foldedtubular section length210 is shorter in the fully deployed state or implanted state (seeFIG. 2B) than the nondeployed foldedtubular section length185 in the non-axially deployed state shown inFIG. 2A. The straight deployed proximaltubular section length215 and the deployed distaltubular section length220 are longer in the deployed state as shown inFIG. 2B than the straight nondeployed proximaltubular section length150 and the nondeployed distaltubular section length200, respectively in the non-axially deployed state. It is possible for the deployed distaltubular section length220 to have increased more in length than the straight deployed proximaltubular section length215 as the straight intravascular foldedtubular member95 goes from a partially deployed state to a fully deployed state. Alternately, both the straight deployed proximaltubular section length215 and deployed distaltubular section length220 could have increased the same amount as the straight deployed tubular member length has extended from a partially deployed state to a fully deployed state as will be explained further later. All reference numerals correspond to those elements previously or otherwise described.
• FIGS. 2C and 2D show cross sectional views of the straight intravascular foldedtubular member95 in a nondeployed state, a non-radially deployed state, or insertion state. The length of the straight intravascular folded tubular member inFIGS. 2C and 2D is the same as inFIG. 2A. In one embodiment for delivering or inserting a self-expanding straight intravascular foldedtubular member95, for example, anouter delivery sheath225 holds the straight intravascular foldedtubular member95 with a smaller insertion diameter or nondeployed inlet end diameter230 and with a smaller insertion diameter or nondeployedoutlet end diameter235. To deliver the straight intravascular foldedtubular member95 to the site of the vascular injury, thedelivery sheath225 containing the straight intravascular foldedtubular member95 is entered into a vessel either proximal or distal to the vascular lesion. Upon removal from thedelivery sheath225, the straight intravascular foldedtubular member95 expands from the nondeployed state to form the partially deployed state with a larger radially deployedinlet end diameter105 and radially deployedoutlet end diameter110 as shown inFIG. 2A. Following delivery of the straight intravascular foldedtubular member95 to the site of the lesion, the straight intravascular foldedtubular member95 is extended from a straight nondeployedtubular member length115 to an appropriate straight deployedtubular member length205 representative of an implanted state. Mechanical dilitation of the tubular member can be further employed if needed such as with a balloon dilitation catheter to expand the straight intravascular foldedtubular member95 to its radially deployedinlet end diameter105 and radially deployedoutlet end diameter110 to ensure that the straight intravascular folded tubular member has attained a larger deployed diameter237 (seeFIGS. 2A and 2B). Thedelivery sheath225, in addition to a balloon dilitation catheter, or other delivery system means can be used to deliver the straight intravascular foldedtubular member95 to the site of vascular injury and deploy it from a nondeployed state or insertion state with a smaller insertion diameter or nondeployed diameter to a deployed state or implanted state with a larger deployeddiameter237 or implanted diameter. The straight intravascular folded tubular member can also be a balloon-expandable device. In this case the straight intravascular folded tubular member, either with or without an attachment means can be mounted in a nondeployed state onto the balloon of a balloon dilitation catheter. Upon delivery to the site of the lesion, the balloon can be expanded to cause the straight intravascular folded tubular member to assume its radially deployed state.
• FIG. 2E shows a straight intravascular foldedtubular member95 in an unfolded state with a straight unfoldedtubular member length240 prior to forming the foldedtubular section125 shown inFIGS. 2A and 2B. The straight intravascular foldedtubular member95 can be formed out of any material used in vascular grafts, in stent-grafts, or implanted vascular conduits such as tubular expanded polytetrafluoroethylene (ePTFE), woven expanded polytetrafluoroethylene fibers, woven or knitted polyester, polyurethane, silicone, or other materials such as composite woven or braided materials presented later in this disclosure.
• The straight intravascular foldedtubular member95 can have but is not required to have an attachment means87 at the inlet and outlet end148 as shown inFIG. 3. This attachment means can be a prior art stent used for vascular implant. Such an attachment means87 if present generally serves to hold the straight intravascular foldedtubular member95 in place and ensure a leak free fit with the native vessel proximal or distal to the vessel injury. The straight intravascular foldedtubular member95 can be placed within a blood vessel and with theinlet end145 and outlet end148 being attached to the native vessel using a separate prior art stent or attachment means of any type that is placed near theinlet end145 and outlet end148 to form an attachment with the native vessel. If appropriate, a surgical cutdown could be conducted and sutures used to hold theinlet end145 and outlet end148 of the straight intravascular foldedtubular member95 in place with a leak free seal. The straight intravascular foldedtubular member95 could also be formed from a material that maintained a tubular or cylindrical shape with an outward extending force and did not require an attachment means. Existing vascular graft materials including polyurethane, silicone, and others are capable of providing this characteristic and may not require an additional attachment means in some implant situations. Such implant situations include repair of blood vessels with luminal injury that would benefit by a vascular graft but with adequate vessel integrity and anatomy such that graft migration and sealing are not of acute concern.
• It is often times preferable to include an attachment means87 to ensure a tight seal between the straight intravascular foldedtubular member95 and the vessel wall and to prevent migration of the straight intravascular foldedtubular member95. Anattachment anchor245 which is included in the present invention and is discussed in more detail later in this disclosure is shown attached to theinlet end145 and outlet end148 of the straight foldedtubular member95.FIG. 3 shows the straight intravascular foldedtubular member95 in a deployed state with theattachment anchor245 containingbarbs250 attached to the straight proximaltubular section120 near theinlet end145 with securingfibers255 or other securing means. Almost any attachment means such as a stent found in the prior art can be used as the attachment means for theinlet end145 and outlet end148 of the straight intravascular foldedtubular member95. Theattachment anchor245 of the present invention shown inFIG. 3 can provide more enhanced anchoring properties than found with other prior art attachment means and will be discussed later in this disclosure. Theattachment anchor245 withbarbs250 is positioned on theinner surface135 of the straight intravascular foldedtubular member95 such that it forcibly holds the straight intravascular foldedtubular member95 outward against the vessel wall after theattachment anchor245 has been deployed to a larger diameter. Theattachment anchor245 hasbarbs250 that extend outward to provide enhanced anchoring of the straight intravascular foldedtubular member95 to the vessel wall. This anchoring helps to prevent migration of the straight intravascular foldedtubular member95 and in the case of abdominal aortic aneurysm repair can help to support the aortic wall from further aneurysmal dilitation. Theattachment anchor245 withoutbarbs250 is shown attached to the distaltubular section130 at or near theoutlet end148 with securingfibers255. Theattachment anchor245 is positioned on the inside of the straight intravascular foldedtubular member95 such that it forcibly holds the straight intravascular foldedtubular member95 outward against the vessel wall. For ease of description, the straight intravascular foldedtubular member95 is shown with anattachment anchor245 withbarbs250 attached to the straight proximaltubular section120 and anattachment anchor245 withoutbarbs250 attached to the distaltubular section130. Either the straight proximaltubular section120 or the distaltubular section130 could have theattachment anchor245 with or withoutbarbs250 attached and still be within the teachings of the present disclosure.
• Another embodiment of the present invention is a bifurcated intravascular foldedtubular member260 shown inFIGS. 4A-4D and described collectively below. This embodiment is intended for vascular repair of a blood vessel trunk that has a bifurcation wherein one or both native vessel legs bifurcating off of the vessel trunk are also in need of repair. Blood flow from the common blood vessel trunk of the vessel proximal to the site of vessel injury into the bifurcated intravascular foldedtubular member260. The bifurcated intravascular foldedtubular member260 has aninlet end145 that provides passage for blood flow into the bifurcated intravascular folded tubular member260 (seeFIG. 4B). The bifurcated intravascular foldedtubular member260 has two outlet ends148 that provide passage for blood flow out of the bifurcated intravascular foldedtubular member260 into two distal vessels located distal to the vessel lesion. One common application for this embodiment is in the repair of abdominal aortic aneurysms where one or both common iliac, external iliac, or femoral arteries are involved in the aneurysmal dilation of the vessel wall. The bifurcated intravascular foldedtubular member260 has a bifurcated proximaltubular section265 with aninlet end145, a bifurcatedmain trunk270 joined either contiguously or with an attachment to twoproximal leg tubes275. The bifurcated intravascular foldedtubular member260 has aninner surface135 and anouter surface140. Each of theproximal leg tubes275 are joined either contiguously or with an attachment to a foldedtubular section125. Each foldedtubular section125 is joined either contiguously or with an attachment to a distaltubular section130. Each distaltubular section130 has anoutlet end148 that provides passage for blood flow out of each distaltubular section130 and out of the bifurcated intravascular foldedtubular member260.
• The bifurcated intravascular foldedtubular member260 is shown in a partially deployed state inFIG. 4A. Theinlet end145 has a larger radially deployedinlet end diameter105 and eachoutlet end148 has a larger radially deployedoutlet end diameter110. A continuous intravasculartubular member wall143 extends from theinlet end145 to eachoutlet end148. The continuous intravasculartubular member wall143 can have attachments between the bifurcated proximaltubular section265, the foldedtubular section125, and the distaltubular section130 of the intravasculartubular member wall143 or the intravasculartubular member wall143 can be contiguous without attachments. The radially deployed bifurcated intravascular foldedtubular member260 has a shorter bifurcated nondeployedtubular member length280 than the bifurcated deployedtubular member length290. The bifurcated intravascular foldedtubular member260 shown in this embodiment is similar to the straight intravascular foldedtubular member95 shown inFIGS. 2A-2D except that the present embodiment has a bifurcated proximaltubular section265 that is bifurcated and it has two foldedtubular sections125 joined to the bifurcated proximaltubular section265 instead of one, each foldedtubular section125 being joined to a distaltubular section130. The structure of each foldedtubular section125 of the bifurcated intravascular foldedtubular member260 is the same as the structure of the foldedtubular section125 of the straight intravascular foldedtubular member95 shown inFIGS. 2A-2E. Each foldedtubular section125 has a continuous tubular wall that is folded back and forth upon itself to form a folded tubular sectioninner wall165, a folded tubularsection center wall160, and a folded tubular sectionouter wall155. In the folded tubular section125 a portion of theinner surface135 is in apposition with another portion of theinner surface135. In the folded tubular section125 a portion of theouter surface140 is in apposition with another portion of theouter surface140. Each foldedtubular section125 has a proximalcircumferential fold line175 to a distalcircumferential fold line180 and has a nondeployed foldedtubular section length185 extending between the proximal175 and distal180 fold lines. Each foldedtubular section125 has a wall with anupstream end187 and adownstream end188. The wall of the bifurcated proximaltubular section265 is joined to folded tubular sectionupstream end187, and the distaltubular section wall190 is joined to the folded tubular sectiondownstream end188. The bifurcated proximaltubular section265 has a bifurcated nondeployed proximaltubular section length285 and the distaltubular section130 has a nondeployed distaltubular section length200. The nondeployed distaltubular section length200 can have significant length to accommodate a variety of vascular applications with varying lengths of vascular injury. Alternately, the nondeployed distaltubular section130 can have negligible length and the distaltubular section130 can consist of theoutlet end148. All reference numerals correspond to those elements previously or otherwise described.
• FIG. 4B shows the bifurcated intravascular foldedtubular member260 in a fully deployed state or implanted state, being deployed to both a larger radially deployedinlet end diameter105, a larger radially deployedoutlet end diameter110, and a longer bifurcated deployedtubular member length290. During full deployment to a bifurcated deployedtubular member length290, the bifurcated proximaltubular section265 extends in length to a bifurcated deployed proximaltubular section length295, the distaltubular section130 extends in length to a deployed distaltubular section length220, and the foldedtubular section125 reduces in length to a deployed foldedtubular section length210. This extension in length from a shorter bifurcated nondeployedtubular member length280 to a longer bifurcated deployedtubular member length290 is accomplished as the foldedtubular section125 unfolds an appropriate amount to achieve an appropriate bifurcated deployedtubular member length290 for the bifurcated intravascular foldedtubular member260. During the unfolding process it is possible for either the bifurcated nondeployed proximaltubular section length285 or the nondeployed distaltubular section length200 to extend more than the other tubular section length extends in forming the bifurcated deployedtubular member length290.
• The bifurcated intravascular foldedtubular member260 is generally intended to be delivered to the site of a lesion such as an aortic aneurysm in a nondeployed or insertion state as shown in cross section inFIGS. 4C and 4D.FIG. 4C shows a cross sectional view of the bifurcated intravascular foldedtubular member260 near theinlet end145 in a nondeployed state;FIG. 4D shows a cross sectional view of the bifurcated intravascular foldedtubular member260 near theoutlet end148 in a nondeployed state. Aguidewire298 is shown extending through onedistal tubular section130 ofFIG. 4D and through the center of the bifurcated proximaltubular section265 inFIG. 4C. The bifurcated intravascular foldedtubular member260 can also be mounted on a balloon dilitation catheter300 (seeFIG. 4E) and delivery system capable of expanding the bifurcated intravascular foldedtubular member260 from a nondeployed state or insertion state to a larger deployeddiameter237 representative of the radially deployed state ofFIG. 4A or fully deployed state ofFIG. 4B. As anintravascular tubular member85 of the present invention the straight intravascular foldedtubular member95 and the bifurcated intravascular foldedtubular member260 are intended to be delivered to the site of vascular injury with a smaller nondeployed diameter305 that can easily fit within a small surgical access or percutaneous access in a blood vessel either proximal or distal to the vascular injury. Once the intravascular tubular member is delivered to the site of vessel injury it will expand out to larger deployeddiameter237 that is approximately equal to the diameter of the native vessel that is to be repaired. In one embodiment the bifurcated intravascular foldedtubular member260 can be held with a smaller nondeployed inlet end diameter230 and nondeployedoutlet end diameter235 by adelivery sheath225. For treatment of abdominalaortic aneurysm5 thedelivery sheath225 containing the bifurcated intravascular foldedtubular member260 is generally introduced into onecommon femoral artery30 and advanced proximally through thenative lumen53 of the commoniliac artery20 andabdominal aorta10 to the proximalaortic neck90 generally located just distal to therenal arteries45 &50 (seeFIGS. 1A and 1B). The bifurcated intravascular foldedtubular member260 is released from thedelivery sheath225 such that theinlet end145 is positioned distal to therenal arteries45 &50 and the bifurcated intravascular foldedtubular member260 expands to the radially deployedinlet end diameter105. This can be accomplished, for example, for a bifurcated intravascular folded tubular member that is self-expandable or has an attachment means attached to the inlet or outlet ends that is self-expandable. Thedelivery sheath225 is removed delivering the bifurcated intravascular foldedtubular member260 to theabdominal aorta10 in a partially deployed state as shown inFIG. 4A. Alternately, the present invention can be made to expand from a nondeployed state of smaller nondeployed inlet end diameter230 or nondeployedoutlet end diameter235 to a deployed state of larger radially deployedinlet end diameter105 or radially deployedoutlet end diameter110 using a mechanical expansion device such as aballoon dilitation catheter300. In this case the bifurcated intravascular folded tubular member or the attachment means which can be attached thereto can be balloon-expandable. Each outlet end148 of the two distal tubular sections is positioned at the appropriate location within the commoniliac artery20, externaliliac artery25, or commonfemoral artery30. This positioning causes each of the folded tubular sections to unfold to provide the appropriate lengths for each of the two deployed foldedtubular section lengths210. The bifurcated intravascular foldedtubular member260 is then fully deployed and extends from a region of the abdominal aorta proximal to the vessel injury or aneurysm to two distal iliac or femoral arteries. Theinlet end145 of the bifurcated intravascular foldedtubular member260 provides passage for blood flow from the abdominal aorta proximal to the vessel injury into theblood flow passage100 and each outlet end148 providing passage for blood flow to each of two distal arteries located distal to the vessel injury.FIG. 4F shows the bifurcated intravascular foldedtubular member260 in an unfolded state with a bifurcated unfoldedtubular member length315 as it might appear prior to forming each foldedtubular section125 found inFIGS. 4A and 4B. All reference numerals correspond to those elements previously or otherwise discussed.
• An additional preferred embodiment of a bifurcated intravascular foldedtubular member260 is shown inFIG. 5 with anattachment anchor245 or other attachment means87 at theinlet end145 and at eachoutlet end148. The attachment means87 can be any barbed or non-barbed attachment means found in the prior art or device that can be used to anchor the ends of an intravascular tubular member. The attachment means87 serves to hold the bifurcated intravascular foldedtubular member260 firmly against the vessel wall at itsinlet end145 and outlet end148 to prevent migration, and reduce leakage between the bifurcated intravascular foldedtubular member260 and the native lumen53 (seeFIGS. 1A and 1B). The bifurcated intravascular foldedtubular member260 is not required to have an attachment means. A separate stent such as found in the prior art placed on theinner surface135 at theinlet end145 and outlet end148 of the bifurcated intravascular foldedtubular member260 can be used to prevent migration and leakage. At the inlet end145 anattachment anchor245 of the present invention withbarbs250 similar to that shown inFIG. 3 can be attached. Thisattachment anchor245 will be described in detail later in this disclosure. Securingfibers255 or other securing means attach theattachment anchor245 to theinner surface135 of the bifurcated proximaltubular section265 near theinlet end145. Theattachment anchor245 withbarbs250 can be short to allow it to be placed more accurately near the renal arteries without extending distally beyond the aortic neck into the aneurysmal space. Theattachment anchor245 shown allows an increased number ofbarbs250 to be positioned along the circumference of theattachment anchor245. This increased number ofbarbs250 allows the bifurcated intravascular foldedtubular member260 to be anchored well to the aortic wall to prevent leakage of blood, prevent migration, and may also provide some additional support to prevent further dilation of the abdominal aorta. Anattachment anchor245 withoutbarbs250 is attached to theinner surface135 of each distaltubular section130 at each outlet end148 using securingfibers255. Eachattachment anchor245 either with or withoutbarbs250 can be constructed out of an elastic metal such as Nitinol, stainless steel, or other metal or metal alloy that provides theattachment anchor245 with a self expanding characteristic. Alternately, theattachment anchor245 can be formed out of a metal such as stainless steel, titanium, tantalum, platinum, or other metal or metal alloy that undergoes plastic deformation to attain a deployedattachment anchor diameter320.
Unfolding of Folded Tubular Section
• It can be desirable for the foldedtubular section125 to unfold evenly or in a controlled manner without wrinkling as it moves from a nondeployed foldedtubular section length185 to a deployed foldedtubular section length210. Furthermore it is desirable for the folded tubular section125 (seeFIG. 4B) to remain at a constant deployed foldedtubular section length210 with the straight or bifurcated intravascular foldedtubular member95 &260 in a fully deployed state.FIG. 6 shows the nondeployed state of the foldedtubular section125 including its junction to the straight proximaltubular section120 and its junction to the distaltubular section130. This discussion applies equally well for the foldedtubular section125 joined to the bifurcated proximal tubular section265 (seeFIGS. 4A and 4B). As shown inFIG. 6 abonding agent325 can be applied to the portion of theouter surface140 of the foldedtubular section125 that is in apposition with another portion of theouter surface140 of the foldedtubular section125. Thebonding agent325 can be an adhesive such as cyanoacrylate, epoxy, polyurethane, or other adhesive that would allow the bonded region to peel at the proximalcircumferential fold line175 preferential to the distalcircumferential fold line180 and allow expansion of the straight intravascular foldedtubular member95 from a straight nondeployedtubular member length115 to a straight deployedtubular member length205 as described earlier inFIGS. 2A and 2B. The adhesive would resist wrinkling of the folded tubularsection center wall160 due to relative movement or slippage of the folded tubularsection center wall160 with respect to the folded tubular sectioninner wall165 or folded tubular sectionouter wall155. Placement of thebonding agent325 on the portions of theouter surface140 of the foldedtubular section125 which are in apposition would not significantly affect thrombosis of the straight intravascular foldedtubular member95 or bifurcated intravascular folded tubular member260 (seeFIGS. 4A and 4B) since theouter surface140 is not in contact with blood flow. Placement of thebonding agent325 on theouter surface140 of the foldedtubular section125 that is in apposition can allow the distaltubular section130 to elongate preferentially to, or with a greater length change than, the straight proximaltubular section120 or bifurcated proximal tubular section265 (seeFIGS. 4A and 4B) for the case of the bifurcated intravascular foldedtubular member260. Abonding agent325 that would not create thrombosis could also be applied to the portions of theinner surface135 of the foldedtubular section125 that were in apposition. This would further reduce wrinkling of the folded tubularsection center wall160 and allow the foldedtubular section125 to unfold in a controlled manner, with unfolding providing for more even extension of the straight proximaltubular section120 with respect to the distaltubular section130.
• The unfolding of the folded tubular sectioninner wall165, folded tubularsection center wall160, and folded tubular section outer wall155 (seeFIGS. 2A and 4A) can be seen more clearly in the schematic sectional drawings ofFIGS. 7A-7E which show foldedtubular section walls330 along with their junction to the straight proximaltubular section wall170 and the distaltubular section wall190. It is understood that this teaching of unfolding applies equally well to each foldedtubular section125 found in the bifurcated intravascular foldedtubular member260 ofFIGS. 4A and 4B.FIG. 7A shows the foldedtubular section125 having the foldedtubular section walls330 with theouter surface140 of the folded tubular sectioninner wall165 in apposition with theouter surface140 of the folded tubularsection center wall160. Theinner surface135 of the folded tubularsection center wall160 is in apposition with theinner surface135 of the folded tubular sectionouter wall155. Markers in the form of acircle335, square340, point-uptriangle345 and point-downtriangle350, andrectangle355 mark positions on the foldedtubular section125 ofFIG. 7A with a nondeployed foldedtubular section length185 for reference purposes. InFIG. 7B the deployed foldedtubular section length210 has been reduced as the folded tubularsection center wall160 from thecircle335 to therectangle355 has unfolded to become the folded tubular sectioninner wall165. The straight deployed proximaltubular section length215 has lengthened from the straight nondeployed proximaltubular section length150 more than the deployed distaltubular section length220 has increased from the nondeployed distaltubular section length200. This form of unfolding can generally occur when bondingagent325 is placed only on portions of the inside surface of the foldedtubular section125 in apposition with another portion of inside surface. InFIG. 7C the deployed foldedtubular section length210 has been reduced fromFIG. 7A as the folded tubularsection center wall160 from therectangle355 to the square340 has unfolded to become the folded tubular sectionouter wall155. The deployed distaltubular section length220 has lengthened more than the straight deployed proximaltubular section length215 has lengthened. This form of unfolding can be generated by placement of abonding agent325 on portions or theouter surface140 of the foldedtubular section125 in apposition with another portion of outside surface as described inFIG. 6. InFIG. 7D the deployed foldedtubular section length210 has been reduced from the nondeployed foldedtubular section length185 shown inFIG. 7A as a portion of the folded tubularsection center wall160 has unfolded to become a portion of both the folded tubular sectioninner wall165 and the folded tubular sectionouter wall155. The straight deployed proximaltubular section length215 and the deployed distaltubular section length220 have both increased. This form of unfolding can occur if the folded tubular sectioninner wall165 and folded tubular sectionouter wall155 unfold evenly. Placing an effectivelysimilar bonding agent325 on both theinner surface135 andouter surface140 can result in this even unfolding pattern. Similar results can occur with no bonding agent placed on the foldedtubular section125. InFIG. 7E the deployed folded wall section length has been reduced fromFIG. 7A. The folded tubularsection center wall160 has not unfolded but has rather wrinkled to allow the straight deployed proximaltubular section length215 and the deployed distaltubular section length220 to increase. The use of abonding agent325 as explained inFIG. 6 can enhance the ability of the straight intravascular foldedtubular member95 and bifurcated intravascular foldedtubular member260 of the present invention to unfold in a manner similar to the methods described inFIGS. 7A-7D and not wrinkle in an uncontrolled manner as shown inFIG. 7E.
• FIG. 8 shows a foldedtubular section125 with holdingpins360 extending through the folded tubular sectioninner wall165, folded tubularsection center wall160, and folded tubular sectionouter wall155. Following full deployment of the straight intravascular foldedtubular member95 or bifurcated intravascular foldedtubular member260 such holding pins360 or other form of holding means can be placed to ensure that further elongation of the intravascular tubular member cannot occur. The holding pins360 can be the same as thebarbs250 located on theattachment anchor245 of the present invention.
Attachment Anchor
• FIG. 9A is an isometric view of an embodiment of theattachment anchor245 of the present invention without barbs in a nondeployed state.FIGS. 9A-9C will be discussed collectively. Thisattachment anchor245 is similar to the attachment anchor shown inFIG. 5 except that thebarbs250 are not present. Theattachment anchor245 of the present invention is comprised entirely out ofnodes365 and struts370 arranged in a ring structure. Theattachment anchor245 of the present embodiment is comprised of a series ofnodes365 and struts370 arranged in a generally cylindrical shape. The axially orientedstruts370 are separated byinterstrut openings375. Each of thenodes365 include at least onehinge380 and have anintranodal opening385 that connects with one of theinterstrut openings375. Thisattachment anchor245 can be machined from a metal cylinder using machining techniques including mechanical machining, laser machining, chemical machining, electrochemical etching, electric discharge machining, and other machining methods. The metal used in the formation of theattachment anchor245 can include stainless steel, Nitinol, tantalum, titanium, platinum, gold, or other metals or metal alloys. Nitinol, some stainless steel compositions, or other metals with elastic properties are suited to anattachment anchor245 that is self-expandable; other stainless steel compositions, titanium, and other metals or metal alloys with plastic deformation properties can be suited to anattachment anchor245 that is balloon-expandable. The metal can be chosen to provide a high yield strength or have a high elastic modulus or Young's modulus that can provide theattachment anchor245 with a high expansion force while maintaining a lower profile and a more supple feel in a crushing deformation. A crushing deformation tends to deform the generally cylindrically shapedattachment anchor245 into an oval shape. The design of thenodes365 and thestruts370 can be chosen to provide appropriate outward expansion forces by theattachment anchor245 for a particular application. Typically a larger diameter and thicker walled blood vessel would require anattachment anchor245 with greater expansion forces outward against the blood vessel wall than a smaller diameter, thinner walled blood vessel. Theattachment anchor245 must provide adequate outward expansion force to hold the intravascular tubular member of the present invention outward against the blood vessel wall without leakage, it must resist any compression forces offered by the blood vessel, and it must prevent migration of the intravascular tubular member. Theattachment anchor245 is a radially expandable vascular implant that can be a self-expandable attachment anchor245 or a balloon-expandable attachment anchor245. The design of thenode365 can be altered to provide for a completely elastic deformation of the metal in thehinge380 or to provide for plastic deformation of the metal in thehinge380. Theintranodal openings385 provide sites for attachment of securing fibers255 (seeFIGS. 3 and 5) to theattachment anchor245 in order to hold theattachment anchor245 to a straight intravascular foldedtubular member95, or to a bifurcated intravascular foldedtubular member260 as described inFIGS. 3 and 5, or to any other tubular member or tubular means that is used as an intravascular graft or intravascular tubular member. Theattachment anchor245 of the present invention can be used with other prior art stent-graft devices to anchor such devices to a blood vessel. In a nondeployed state, thestruts370 are adjacent and parallel to each other and in direct apposition to each other to provide the closest position ofstruts370 with respect to each other. This provides theattachment anchor245 with an ability to attain the largest expansion ratio of attachment anchor diameters from a deployed state to a nondeployed state. The attachment anchor has a hinge width radius of curvature386 (FIG. 9B) which describes the radius of curvature with the direction of the radius of curvature aligned with the direction of the hinge width420 (FIG. 9C). Theattachment anchor245 has a nondeployedattachment anchor diameter387.
• FIG. 9A shows an isometric view of theattachment anchor245 in a nondeployed state with a smallernondeployed diameter387 or insertion diameter andFIG. 9B shows theattachment anchor245 in a deployed state with a larger deployedattachment anchor diameter380. Thestrut length390 remains constant from the nondeployed or insertion state to the deployed or implanted state. A deployed attachment anchor length395 in anaxial direction398 is shorter than the nondeployedattachment anchor length400 but the amount of length change is minimal due in part to the increased number of deformation sites ornodes365 found in thepresent attachment anchor245 in comparison to other prior art attachment devices. Additionally, the greater number of deformation sites or nodes allows each deformation site to undergo a smaller deformation with less attachment anchor length change. Theinterstrut openings375 between thestruts370 in acircumferential direction403 in a nondeployed state can be negligible and thestruts370 can be in direct contact with each other. The generally cylindrical shape of the attachment anchor has a generally cylindrical uniformly curvedattachment anchor surface404 formed by thestruts370 andnodes365. In addition, the attachment anchor can be deployed to asmall deployment angle405 of less than 60 degrees which further reduces the amount of attachment anchor length change in going from a nondeployed state to a deployed state. The deployment of theattachment anchor245 to a smaller deployedangle405 in comparison to other prior art attachment devices can be accomplished due to the greater number ofnodes365 found on thepresent attachment anchor245. Alternately, theattachment anchor245 of the present invention can be deployed to alarger deployment angle405 than other prior art attachment means formed with round wires due to the greater force that can be generated by thehinge380 of the present invention in comparison to a round wire. This greater force can be generated due to the hinge design and due to the higher modulus material that can be used for the hinge. Thelarger deployment angle405 can provide thepresent attachment anchor245 with a greater expansion ratio of deployedattachment anchor diameter320 to nondeployedattachment anchor diameter387. Theattachment anchor245 is deployed from a smaller insertion diameter or nondeployedattachment anchor diameter387 in its nondeployed or insertion state to a larger deployedattachment anchor diameter320 or insertion diameter in its deployed or implanted diameter. The ratio of deployedattachment anchor diameter320 to nondeployedattachment anchor diameter387 is maximized by positioning thestruts370 parallel and in apposition to each other in the nondeployed state.
• FIG. 9C is an enlarged isometric view of a portion of theattachment anchor245 shown inFIG. 9A. Each of thenodes365 comprises thehinge380 and twotransition regions410. Thehinge380 has ahinge length415, ahinge width420, and a hingeradial dimension425. Thestrut370 has astrut width430, a strutradial dimension435, and astrut length390 as shown inFIG. 9A. Thehinge380 has a greater hingeradial dimension425 than the strutradial dimension435 and thehinge380 has asmaller hinge width420 than thestrut width430. Each of thetransition regions410 extends from thehinge380 to thestrut370. It has atransition width440 that varies from thesmaller hinge width420 to thelarger strut width430 and a transitionradial dimension445 that varies from the larger hingeradial dimension425 to the smaller strutradial dimension435. Thetransition regions410 provides a smooth uniform transition of metal strength and conformation from eachhinge380 to each of thestruts370. Thestruts370 have a strut crosssectional area447 that can be different from and varied independently from a hinge crosssectional area448. As shown inFIGS. 9A and 9B theattachment anchor245 has a nondeployedattachment anchor perimeter449 and a deployedattachment anchor perimeter451. Thetransition regions410 have an abrupttransition region length452 that is as short as possible without causing a discontinuity in cross sectional area in order to maximize thehinge length415 andstrut length390. The cross sectional areas of the transition regions are maintained to be larger than either the strut crosssectional area447 or the hinge crosssectional area448.
• An embodiment of theattachment anchor245 is a self-expandable vascular implant that can be used with the straight intravascular foldedtubular member95, bifurcated intravascular foldedtubular member260 of the present invention, or with any other intravascular tubular means that is used for intravascular repair of blood vessels. Thehinge length415 can be long, extending approximately from one of thetransition regions410 to another as shown inFIG. 9C and having ahinge length415 equal to or greater than approximately twice thestrut width430. For a self-expandable attachment anchor245 with along hinge length415 several advantages are obtained over prior art attachment devices such as those formed from zig zag shaped wire. Thelong hinge length415 provides a smaller drop-off of the expansion elastic force exerted outward against the vessel wall by theattachment anchor245 as theattachment anchor245 extends from a nondeployed state to a deployed state with an elastic deformation. This smaller drop-off of outward expansion force provides a similar outward force over a variety of diameters for which the same attachment anchor can be used. Theattachment anchor245 of the present invention can therefore exert a greater outward force in a fully deployed state as shown inFIG. 9C than one with ashorter hinge length415 andsimilar hinge width420 and hingeradial dimension425 and the same outward expansion force in a nondeployed state. In addition, thehinge380 of thepresent attachment anchor245 is responsible for generating the outward force, and thehinge380 is positioned with significantcircumferential direction403. Thestrut370 does not significantly contribute to generating the outward expansion force generated by theattachment anchor245. The deployed or nondeployed attachment anchor length395 &400, in substantially anaxial direction398, can be smaller than other prior art or zig zag wire type attachment devices that provide similar outward expansion forces. This allows theattachment anchor245 to form a more focused line attachment to the vessel wall consisting of a ring of small axial length in theaxial direction398 for contact between theattachment anchor245 and the vessel wall or a focused attachment between theattachment anchor245 and thevascular tubular member85 that resides between theattachment anchor245 and the blood vessel wall. Prior art zig zag wire attachment devices have a portion of the wire bent in a hair-pin turn and another portion that is not bent as significantly forming a wire strut. Prior art zig zag wire attachment devices generate a majority of their elastic outward force from the portion that is significantly bent. These prior art devices rely in part on the bending of the wire that is not significantly bent to generate the elastic force that is exerted outward against the vessel wall. These bending wires from zig zag wire attachment devices extend in significantly anaxial direction398 with a greater axial length than the struts of an embodiment of the present invention. Theattachment anchor245 of the present invention can be constructed with a smaller deployed attachment anchor length395 than prior art devices and can be positioned closer to the renal vessels of the aorta with less chance of distal migration.
• Alternately, theattachment anchor245 of the present invention can be used with a mechanical expanding means such as the dilitation balloon of a balloon expansion catheter. Theattachment anchor245 can be forced to expand due to the dilitation balloon causing the metal located in thehinge380 to deform plastically and hold the intravascular tubular member of the present invention or other intravascular stent-graft out against the aortic wall. Thestruts370 for the balloon-expandable attachment anchor245 do not contribute significantly to the outward expansion force generated by thehinge380 of theattachment anchor245. Thestruts370 transfer the outward expansion force generated by thehinge380 from one node to another to the vessel wall to hold the vessel wall outward, provide a seal, and help prevent migration of the intravascular tubular member. Thehinge380 of theattachment anchor245 can be adjusted inhinge length415,hinge width420, or in hingeradial dimension425 to provide the necessary outward forces to hold theintravascular tubular member85 of the present invention or other prior art intravascular stent-graft outwards against the aorta.
• Theattachment anchor245 of this embodiment, whether a balloon-expandable attachment anchor or a self-expandable attachment anchor, has a single ring structure formed of nodes356 and struts370 with thestruts370 folded back and forth adjacent to each other in the nondeployed state. Thehinge length415,width420, andradial dimension425 provide an expansion deformation in the uniformly curvedattachment anchor surface404 that produces an outward expansion force exerted against the vessel wall or the intravasculartubular member wall143 in its expanded state. Thestruts370 transfer the forces generated by thehinges380 to the vessel or intravasculartubular member wall143. Thestruts370 do not deform within the uniformly curvedattachment anchor surface404 due to thelarger strut width430 in comparison to thehinge width420. If theattachment anchor245 is subjected to a crush deformation such that it forms an ovalattachment anchor surface453, thestruts370 will bend in a radial direction due to the relatively small strutradial dimension435 with an elastic deformation. The strut length, width, and radial dimension all provide the strut with an ability to flex elastically during the crush deformation. The hinge will not deform in the radial direction upon exposure to a crush deformation due to the large hingeradial dimension425 in comparison to the strutradial dimension435. Alonger strut length390 along with a fewer number of nodes will allow theattachment anchor245 to have a greater percentage of the attachment anchor associated with thestruts370 in comparison to thehinges380 and hence provide the attachment anchor with a greater flexibility in bending due to a crush deformation.
• Other prior art attachment means including those with zig zag designs have a long axial length to reduce the number of zig zags that are used around their circumference and hence reduce the amount of volume occupied by the attachment means per axial length times the deployed diameter. Most zig zag designs in a nondeployed state consist of a series of hair pin turns connected by straight wire segments that are generally not parallel to each other. The hair pin turns have a radius of curvature that limits the number of hair pin turns that can be used or that will fit along a circumference of an attachment means. Theattachment anchor245 of the present invention hasstruts370 that are generally parallel to each other and can be in direct apposition or contact with each other in a nondeployed state (seeFIG. 9A) and eachhinge380 is machined such that it is smaller inhinge length415 than a curvature diameter for the hair pin turn for the attachment means of the prior art. Thehinge length415 can have a length of approximately twice thestrut width430. The hinge conformation allows it to generate a larger outward force than that generated by prior art wire hair-pin turns formed with a similar curvature diameter. Therefore, manymore nodes365 of the present invention each with ahinge380 can be placed around the circumference of thenondeployed attachment anchor245. This greater number ofnodes365 and accompanyingstruts370 allows each of thestruts370 to be shorter in length than other prior art attachment means in order to achieve a specific expansion ratio of deployeddiameter237 to nondeployed diameter238 and a specific outward force. The presence of thehinge380 allows the outward expansion force provided by theattachment anchor245 within the uniformly curvedattachment anchor surface404 to be controlled by setting the hingeradial dimension425,hinge length415, andhinge width420. The expansion deformation occurs with the hinges deforming within the uniformly curvedattachment anchor surface404. A higher strength metal can be used with thepresent hinge380 allowing a greater outward expansion force to be exerted with athinner hinge width420 or with less metal volume pernondeployed hinge length415 being used in theattachment anchor245. This provides a smaller attachment anchor diameter in the nondeployed state which can fit into a smaller diameter sheath. This outward expansion force is controlled independently from the crush force which is controlled by the strut dimensions.
• A thin strutradial dimension435 can provide theattachment anchor245 with a flexibility to form an ovalattachment anchor surface453 when exposed to a crush deformation by allowing thethin struts370 to bend in the radial direction in forming an oval shape as shown inFIG. 9D. The ovalattachment anchor surface453 ofFIG. 9D that is found when theattachment anchor245 is exposed to crush deformation is not found in the uniformly curvedattachment anchor surface404 which is maintained in a cylindrical shape during normal expansion deformation of theattachment anchor245. The result is that theattachment anchor245 can fit into a smalldiameter delivery sheath225 in its nondeployed or nonexpanded state yet has high expansion force and is flexible in crush deformation. This combination of properties is not possible with the round wire zig zag or other attachment means described in the prior art in which the expansion force and crush force of the attachment device are tied together. Alternately, it is further understood that the strutradial dimension435 can be formed large enough such that thestruts370 will not flex easily if exposed to a crush deformation. In this case the attachment anchor will retain a substantially cylindrical shape with a uniformly curvedattachment anchor surface404 and will be resistant to forming an oval shape characteristic of crush deformation. The strut deformation due to crush is always an elastic deformation and is more easily deformed than the hinge in a radial direction.
• The short attachment anchor length with a greater number ofnodes365, and struts370 allows theattachment anchor245 to be placed such that it is more firmly anchored into healthy blood vessel with a more focal line of attachment to the vessel. For the example of the abdominalaortic aneurysm5, theattachment anchor245 can be placed closer to the aortic neck and nearest to therenal arteries45 &50 in order to get a more firm anchoring into theaortic wall70 and not into thethrombus60 that lines thenative lumen53 for most of the lumen of the abdominal aorta10 (seeFIGS. 1A and 1B). The shorter length also provides an advantage for forming a better seal of the intravascular tubular member with the vessel wall. The shorter length and increased number ofnodes365 further allowsmore barbs250 to be placed along the circumference of theattachment anchor245. This increase in number of barbs250 (seeFIGS. 3 and 5) provides better attachment at an increased number of sites. The result is an increased ability to form a leak free seal between the native blood vessel and theinlet end145 or outlet end148 of any intravascular tubular member or other stent-graft device. Furthermore, theattachment anchor245 with short length and with the increase number ofbarbs250 is more likely to provide an intravascular tubular member or other stent-graft device of any type a greater resistance to distal migration.
• For a self-expandable attachment anchor245 an increase inhinge width420 or hingeradial dimension425 will increase the amount of outward force provided by theattachment anchor245 for thesame deployment angle405 or amount of expansion deformation. Increasing thehinge length415 will result in a smaller drop-off in outward force provided by theattachment anchor245 as it expands from a nondeployed state to a deployed state. Therefore, by changing the dimensions of thehinge380, the outward force delivery characteristics of theattachment anchor245 can be adjusted to provide the desired outward elastic expansion force. Thestrut width430 and strutradial dimension435 can be adjusted to providestruts370 that will remain elastic during the expansion of theattachment anchor245 or during crush deformation with greater flexibility due to bending to an arc with the radius of curvature in the direction of the smaller strutradial dimension435 and more rigidity in the direction of bending of thelarger strut width430. The small strutradial dimension435 allows theattachment anchor245 to be soft and pliable in a crushing type of deformation while maintaining a large expansion force in thecircumferential direction403 needed to hold the blood vessel outward with appropriate force and without leakage between theintravascular tubular member85 and the vessel wall.
• For a balloon-expandable attachment anchor245 the dimensions of thehinge380 can affect its ability to yield under the expansion force of the dilitation balloon and its ability not to yield under the forces applied to it by the aorta. Increasing thehinge width420 and hingeradial dimension425 will increase the amount of yield force that is required to expand theattachment anchor245 from a nondeployed state to a deployed state; it will also increase the amount of yield force that must be exceeded for the aorta to collapse theattachment anchor245. Increasing the hinge width will reduce the amount ofdeployment angle405 that is required before plastic deformation will occur and thehinge380 will no longer return to its original position or equilibrium position with all external forces removed. Reducing thehinge length415 will cause the metal in thehinge380 to deform a greater extent during the expansion from the nondeployed state to the deployed state. Thehinge380 with asmaller hinge length415 will have a greater tendency to undergo a plastic deformation for a smaller expansion deformation. Thestruts370 for the balloon-expandable attachment anchor245 also remain elastic during the expansion deformation as well as during crush deformation.
• An increase instrut length390 also increases the flexibility of theattachment anchor245 in undergoing a crush deformation to an oval shape. Since thestruts370 are smaller in theradial dimension435 than thehinge425 or thetransition region445, the struts bend more easily in the radial direction. Increasing thelength390 of thestruts370 provides a greater percentage of theattachment anchor245 that is associated with thestruts370 in comparison withhinges380 ortransition regions410 and therefore provides a greater flexibility in the radial direction during crush deformation.
• An alternate embodiment for theattachment anchor245 is shown inFIGS. 10A and 10B.FIG. 10A shows theattachment anchor245 in a nondeployed state with theattachment anchor245 not expanded.FIG. 10B shows theattachment anchor245 after it has been expanded to a deployed state. The main difference between this embodiment and the one presented inFIG. 9A-9C is the shape of thenodes365 and the presence of twohinges455 on each of thenodes365. Thenodes365 and struts370 are aligned in series in the same way as the embodiment shown inFIGS. 9A-9C. Eachnode365 of this embodiment is joined to twostruts370 and eachstrut370 is joined to twonodes365 in a manner similar to that shown for the embodiment ofFIGS. 9A-9C. All reference numerals correspond to those elements previously or otherwise described. A detailed isometric view of one of thenodes365 plus a portion of twostruts370 is shown inFIG. 10C. Each of thenodes365 is comprised of ahub457, twohinges455, and twotransition regions410. Thehub457 provides a less flexible portion of eachnode365 to which the two moreflexible hinges455 can be joined. Deformation is substantially less or absent from thehub457. Thetransition regions410 are similar in design and function to thetransition regions410 described inFIG. 9C. The two hinges455 perform a similar function as thesingle hinge380 described inFIG. 9C. Each of thehinges455 has asmaller hinge width420 and a longer hingeradial dimension425 in comparison to thelarger strut width430 and shorter strutradial dimension435, respectively. The length of thetransition region410 is abrupt or short to conserve length that can be used as length for thestruts370 or thehinge380.
• For a self-expandable attachment anchor245 each of thehinges455 is designed to deform elastically during the expansion of theattachment anchor245 from a nondeployed state to a deployed state. A metal of very high yield strength and high elastic modulus can be used for theattachment anchor245 of the present invention. A higher strength metal provides theattachment anchor245 of the present invention with an ability to have all components or elements have a smaller radial dimension than other prior art attachment devices. Increasing the hingeradial dimension425 and thehinge width420 will provide an increase in the outward elastic expansion force provided by theattachment anchor245 in holding theintravascular tubular member85 of the present invention or other intravascular stent-graft against the aorta. Reducing thehinge length415 will provide a larger outward force of theattachment anchor245 against the vessel wall in the deployed state with aspecific deployment angle405 and provided that the hingeradial dimension425 andhinge width420 remain constant for comparison purposes. Thehinge length415 defines the region of thenodes365 wherein the majority of the expansion deformation occurs. Thehinge length415 includes the region of eachnode365 having asmaller hinge width420 than thestrut width430 and that remains approximately constant instrut width430 for a distance. Thehinge length415 can include a region of aminimum hinge width420. Thehinge length415 can be long such as the case shown inFIG. 9C or it can be very short as the case shown inFIG. 10C. With twohinges455 associated with each of thenodes365 it is possible to provide each of thehinges455 of each of thenodes365 with different dimensions and different expansion characteristics. Thehub457 can provide a site for forming a contiguous junction to abarb250. The two hinges455 shown inFIG. 10C can be easier to machine than asingle hinge380 as shown inFIG. 9C.
• For a balloon-expandable attachment anchor245 an increase in the hingeradial dimension425 will cause an increase in the yield force needed by a dilitation balloon to cause theattachment anchor245 to expand and will increase the yield force necessary to cause collapse of theattachment anchor245 due to compressive forces applied by the abdominal aorta or other treated artery on the deployedattachment anchor245. An increase in thehinge width420 will cause the expansion deformation from a nondeployed state to a deployed state to cause more plastic deformation of the metal hinges455 for aspecific deployment angle405 and will require a larger expansion deformation force. Increasing thehinge length415 will reduce the amount of plastic deformation and reduce the rate of change in force for a particular expansion deformation ordeployment angle405. Adjusting thehinge length415,hinge width420, and hingeradial dimension425 allows the balloon-expandable attachment anchor245 to be specifically designed to provide appropriate yield forces for a specific vascular application. This is not able to be accomplished with the wire zig zag or other attachment devices described by the prior art.
Stress Versus Strain
• The stress versus strain relationship for a metal bar or beam such as astrut370 or ahinge380 &455 can in general be estimated by Hooke's law which states that stress applied to the metal bar is equal to an elastic modulus times the strain or deformation to which the bar will deform. This elastic modulus or Young's modulus is a material property characteristic of the particular metal being used for the bar. The deformation can be a bending deformation that is characteristic of the expansion deformation encountered by thestrut370 or thehinge380 &455. A bar in an unstressed state that is exposed to an applied stress below its elastic limit or yield stress will undergo an elastic flexure or elastic deformation which is reversible and the bar will return to its unstressed state upon removal of the applied stress. If the bar is exposed to an applied stress that is larger than its yield stress or if it is deformed to an inelastic flexure that is greater than its elastic limit or proportional limit, or if it is deformed beyond its yield point, plastic deformation will occur and the bar will not return to its original unstressed state with the original conformation or shape of the bar. The bar will generally return part way back to its initial unstressed state due to the elastic portion of the deformation.
• Exposing a bar to a torque or moment can result in bending the bar from a straight shape to a bent conformation with a radius of curvature. The relationship between the applied moment and the radius of curvature can be estimated by the equation that states that moment is equal to Young's modulus times moment of inertia divided by radius of curvature. The moment of inertia is different for different cross sectional shapes of the bar that is being bent. For a bar having a circular cross section and having a diameter, the moment of inertia is given by Pi times the diameter to the fourth power divided by 64. For a rectangular bar cross section with one side of magnitude B and another side of magnitude H, where B is the magnitude of the side in the radial direction of the radius of curvature and H is the magnitude of the side perpendicular to B, the moment of inertia is given by B to the third power times H divided by 12. Similarly, the bar can be bent from one radius of curvature to a second radius of curvature with a similar type of analysis as described above by examining a change in radius of curvature that is comparable to that of starting from a flat surface as just described.
• The hinge crosssectional area448 is equal to the multiplication product of thehinge width420 and the hingeradial dimension425. Eachhinge380 &455 has a large hingeradial dimension425 that does not allow for significant bending deformation along a radius of curvature with a radius aligned along the hinge radial dimension. Bending deformation for eachhinge380 &455 occurs to form a radius of curvature with the radius aligned with thehinge width420, and this radius of curvature is referred to as the hinge width radius ofcurvature386. The hinge can undergo an expansion deformation with bending occurring in the uniformly curvedattachment anchor surface404. The moment of inertia for thehinge380 &455 can be estimated by using thehinge width420 to correspond with the magnitude B and the hingeradial dimension425 to correspond with the magnitude H. The strut crosssectional area447 is equal to the multiplication product of thestrut width430 and the strutradial dimension435. The moment of inertia for each of thestruts370 can be estimated using the strutradial dimension435 to correspond with the magnitude B and thestrut width430 to correspond with the magnitude H. In theattachment anchor245 of the present invention the hinge crosssectional area448 can be varied independently of the strut crosssectional area447 to provide theattachment anchor245 with a variety of expansion force characteristics and other properties. For example, thehinge width420 and hingeradial dimension425 can be equal to the diameter of a round wire and produce a moment that is 1.67 times larger than the round wire based on the equation for moment stated earlier. Thus for a similar magnitude of hinge width in comparison to the diameter of a round wire, theattachment anchor245 in a nondeployed state can provide a greater outward extension force by thehinge380 &455 to thestruts370 than a circular cross sectional or round wire. The hingeradial dimension425 can also be increased in magnitude to provide an even greater moment of inertia to thehinge380 &455 such that even larger moment is generated to produce larger extensional forces by theattachment anchor245. Increasing the hingeradial dimension425 such that it is significantly larger than thehinge width420 will also have a profound effect on increasing the moment of inertia for bending to a radius of curvature with the radius in the radial direction. Hence thehinges380 will not allow bending to occur in the radial direction such as found in thestruts370 in forming an oval shape during crush deformation.
• As another embodiment for the design of theattachment anchor245, the hingeradial dimension425 can be formed such that it is approximately equal to the diameter of a prior art zig zag wire that is used as an attachment means and thehinge width420 can be smaller that the diameter of the zig zag wire. In this embodiment thehinge380 &455 would undergo a smaller amount of localized deformation associated with a bend to a specific radius of curvature than the zig zag wire. Theattachment anchor245 could be formed out of a metal with a higher elastic modulus than the prior art zig zag wire attachment means without undergoing plastic deformation. Thehinge380 &455 of thepresent attachment anchor245 can thus produce an equal or greater moment than a round wire with a diameter larger than thehinge width420 and remain elastic. This embodiment is particularly useful for a self expandingattachment anchor245.
• For a balloon-expandable attachment anchor245 thehinge length415 can be shortened such that the bending deformation of thehinge380 &455 associated with expansion from the nondeployed state to the deployed state exceeds the yield point of the metal used to form theattachment anchor245. For a bending deformation of thehinge380 &455 from one hinge width radius ofcurvature386 to another hinge width radius ofcurvature386, an increase in thehinge width420 will also serve to increase the amount ofhinge380 &455 material exposed to deformation beyond the yield point of the metal. Hence bothhinge length415 andhinge width420 can be adjusted to provide inelastic flexure of the metal and plastic deformation. The hingeradial dimension425 can be further adjusted to control the amount of force that is required to expand theattachment anchor245 to a particular amount of deformation during deployment of theattachment anchor245 and to control the amount of force exerted by theattachment anchor245 against the vessel wall in its deployedattachment anchor diameter320.
• The strut crosssectional area447 can be different than the hinge crosssectional area448 and can be varied independently from it. Thestrut width430 is designed to be large enough such that during expansion of theattachment anchor245 thestruts370 do not bend or flex significantly within the uniformly curvedattachment anchor surface404 of theattachment anchor245 with a radius of curvature in a radial direction aligned with thestrut width430. Thehinge380 &455 can therefore transfer its moment to thestrut370 which then exerts an outward force upon the vessel wall to hold it outwards. Since thestrut width430 and strutradial dimension435 provide a rectangular cross sectional shape for thestrut370 thestrut width430 can be smaller than the diameter of a round wire and provide a greater moment in resisting bending deformation to a radius of curvature with a radius in the direction of thestrut width430. Thestruts370 will not bend in within the uniformly curvedattachment anchor surface404 such as in the direction of theirstrut width430.
• The strutradial dimension435 is formed to be thinner than the hingeradial dimension425 such that it can flex to form a radius of curvature with a radius aligned with the strutradial dimension435; this bending deformation is similar to a crush deformation that would cause theattachment anchor245 to form an ovalattachment anchor surface453 rather than the cylindrical uniformly curvedattachment anchor surface404 that it normally has. Thestruts370 would remain elastic due to its thin wall, due to a choice of metal such that thestruts370 do not exceed the elastic limit of the metal, and due to a longer strut length that distributes the bending along a longer length. The metal chosen for forming theattachment anchor245 could be chosen from a high modulus material and still remain flexible to allow this bending deformation to form an oval shape due to the thin radial dimension. The prior art attachment means formed of a round wire or other prior art structures of high modulus could not provide a combination of a large outward extension force and a low or soft crushing force since the properties of the round wire or other prior art structures affect both the extension force and the crush force. With this embodiment of the present invention, anattachment anchor245 could be formed entirely out of a high modulus metal with thehinge380 &455 providing a large moment for expansion deformation in the uniformly curvedattachment anchor surface404 and thestrut370 allowing theattachment anchor245 to be bent to an oval shape to accommodate variations in the shape of the aorta or other blood vessel. Thehinge380 &455 does not allow bending in the radial direction due to crush deformation forces and thestrut370 does not bend in the uniformly curvedattachment anchor surface404.
• Thestruts370 can be increased in theirradial dimension435 to provide additional resistance to bending in crush deformation. The strut radial dimension is still maintained smaller than the hingeradial dimension425 and smaller than thestrut width430. The strutradial dimension435 is not as large as the hingeradial dimension425 such that the strut always flexes preferentially to the hinge in a crush deformation and thestrut370 is designed to flex elastically. The strut crosssectional area447 has been altered independently of the hinge crosssectional area448. An increase in strutradial dimension435 will provide thestrut370 with a resistance to additional bending to a radius of curvature with a radius aligned with the direction of the strutradial dimension435. This embodiment of theattachment anchor245 will be resistant to crush deformation that would cause theattachment anchor245 to form an oval shape. The strutradial dimension435 is still less than the hingeradial dimension425 and the strut remains elastic when exposed to crush deformation.
• Thestrut length390 for theattachment anchor245 of the present invention can be small and thereby require a greater number ofstruts370 withsmaller strut length390 in order to extend and provide contact with the vessel wall with an adequate outward expansion force. The increased number ofstruts370 andshorter strut length390 provides a more focused line of attachment of theattachment anchor245 to the blood vessel wall. In the case of abdominal aortic aneurysm repair, theattachment anchor245 can be placed closer to the renal arteries with a better attachment to the vessel wall proximal to the thrombus lining. In an expanded state of theattachment anchor245, the moment exerted by eachhinge380 &455 is transmitted to a torque exerted by thestrut370 outward against the vessel wall. This outward torque can be resolved into a product of the outward force against the vessel wall and thestrut length390. Thehinge380 &455 can therefore transfer its moment to thestrut370 which then exerts an outward force upon the vessel wall to hold it outwards.
• Thepresent attachment anchor245 can be optimally suited to provide asmaller strut length390 and a greater number ofstruts370 andnodes365 in order to apply a specific outward force against the vessel or tubular member wall for a nondeployedattachment anchor perimeter449 and a deployedattachment anchor perimeter451. Strut length has an effect upon the flexibility characteristics of the attachment anchor in a crush deformation mode. A longer strut length provides the attachment anchor with a greater percentage of the perimeter of the attachment anchor in a deployed state that is associated with the struts in comparison to the nodes. Since the struts are more flexible in a crush deformation than the nodes, longer strut length provides a greater flexibility in forming an oval shape. To provide an attachment anchor having longer strut length with the same crush flexibility as a shorter strut, the strut radial dimension would be increased to provide the appropriate bending moment in the radial direction. The strut width can be reduced to provide the appropriate resistance to bending in the attachment anchor surface during expansion deformation. Theattachment anchor245 has nodes withhinges380 &455 that are machined into the metal rather than having a wire formed into a loop such as found in prior art attachment means. Eachhinge380 &455 can be machined with a smaller hinge width radius ofcurvature386 than can be formed from a round wire of diameter similar in magnitude to thehinge width420. Furthermore thehinge380 &455 of the present invention can generate a greater moment than can be generated by a round wire as found in prior art attachment means. Thestruts370 are similarly formed by machining to formstruts370 of approximately similar orsmaller strut width430 than the diameter of a round wire of similar strength or moment of inertia allowing thestruts370 to be aligned adjacent to each other or touching each other and parallel to each other in a close packed conformation in a nondeployed state. In a deployed state thepresent attachment anchor245 can provide a greater outward force against the vessel wall due to the greater moment generated by eachhinge380 &455. Thepresent attachment anchor245 can be formed with a nondeployedattachment anchor length400 that is less than approximately 0.20 to 0.30 inches for abdominal aortic aneurysm repair of an aorta with a deployeddiameter237 of approximately 25 millimeters and less than approximately 0.10 to 0.20 inches for anattachment anchor length400 in vessels that are less than approximately 6 millimeters in diameter. The number ofstruts370 along the deployedattachment anchor perimeter451 of theattachment anchor245 can be at least approximately 26 to 32 for abdominal aortic aneurysm repair of an aorta with a 25 millimeter diameter and at least approximately 14 to 20 for use in a vessel of approximately 6 millimeter diameter.
• Alternately, theattachment anchor245 of the present invention can be formed oflarge strut length390 greater than approximately 0.3 inches, athinner strut width430, and a larger strutradial dimension435 and having a lesser number ofstruts370 than the approximately 14 struts stated for the previous embodiment. Theattachment anchor245 of the present invention can be formed with any number ofstruts370 and with anystrut length390 that is suited to a particular application. Thehinge380 &455 of the present invention can provide a greater moment than the moment provided by prior art round wire zig zag attachment means and other prior art attachment means. Therefore thehinge380 &455 of the present invention can transfer a large torque to astrut370 oflarger strut length390 than the length of other prior art round wire struts and provide a greater outward force against the blood vessel to hold it outward than a round wire attachment means. Theattachment anchor245 of the present invention can therefore be used to provide a short or along strut length390 with varying strut radial dimensions and strut widths. The number ofstruts370 can similarly be varied such that anattachment anchor245 withlonger struts370 can be formed withless struts370 than other prior art attachment means.
• Thedeployment angle405 of thepresent attachment anchor245 is generally intended to be small enough such that the change in nondeployedattachment anchor length400 in a nondeployed state to a deployed attachment anchor length395 in a deployed state does not affect the positioning of theattachment anchor245 within the blood vessel prior to deploying it to a deployed state. Atotal deployment angle405 of less than 60 degrees results in a change in the attachment anchor length from the nondeployed state to the deployed state of approximately 15 percent. Thepresent attachment anchor245 can be designed such that thehinge380 &455 will provide anydeployment angle405 from 1 to 80 degrees. To maintain a small change in attachment anchor length from a nondeployed state to a deployed state a deployed angle of less than 45 degrees can be attained by thepresent attachment anchor245. Alternately, in order to provide theattachment anchor245 with the least number ofnodes365 and struts370 while still providing for the greatest expanded deployedattachment anchor diameter320, it is desirable to provide adeployment angle405 that is greater than 45 degrees. Thehinge380 &455 of the present invention can be formed from a metal of large Young's modulus as stated earlier. Thehinge380 &455 can be formed of athin hinge width420 and along hinge length415 such that the moment maintained by thehinge380 &455 will still be adequate even at a large bending deformation angle ordeployment angle405. Thus thehinge380 &455 of the present invention can supply adequate outward force at adeployment angle405 greater than 45 degrees and up to 180 degrees.
• Theattachment anchor245 of the present invention can have one or twohinges455 positioned on eachnode365. For the embodiment with twohinges455, thehinges455 can be equivalent to each other in dimension and perform similarly to having one larger hinge such as asingle hinge380 of another embodiment. Alternately, eachhinge455 on a particular node can be formed with adifferent hinge length415 orhinge width420 than the other. The moment that is generated by eachhinge455 after exposure to a similar bending deformation would therefore be different. Thestruts370 joined via transition regions to each of thehinges455 can be adjusted such that thestrut lengths390 are different. This embodiment of anattachment anchor245 withstruts370 ofdifferent strut length390 connected to the same node can apply a uniform force outward against the blood vessel wall although the longer strut could undergo a greater amount of bending deformation in a crush mode.
• An alternate embodiment for theattachment anchor245 of the present invention is shown in a nondeployed state inFIG. 10D and in a deployed state inFIG. 10E. Theattachment anchor245 is formed entirely out ofnodes365 and struts370 arranged to form a ring with a cylindrical shape. Theattachment anchor245 of this embodiment has a uniformly curvedattachment anchor surface404 in its deployed state shown inFIG. 10D. Theattachment anchor245 of this embodiment has the same description and function for thehinges455,hubs457, and struts370 as were described and shown inFIGS. 10A-10C. The hinges455 have hinge dimensions that allow the hinges to undergo expansion deformation within the uniformly curvedattachment anchor surface404 but will not deform in a radial direction due to a crush deformation. Thestruts370 have strut dimensions that allow them to bend elastically as theattachment anchor245 bends to an oval shape during crush deformation but thestruts370 will not bend in the uniformly curvedattachment anchor surface404.Barbs250 can be a component of any of thenodes365 in a manner described for the embodiment shown inFIGS. 10A-10C. This embodiment can be a balloon-expandable or a self-expandable attachment anchor245. The metal used to form theattachment anchor245 along with the dimensions used for thehinge455 determine whether a plastic deformation or an elastic deformation of thehinge455 will occur during the expansion deformation from a nondeployed state to a deployed state as described earlier for the embodiment shown inFIGS. 10A-10C. This embodiment (seeFIGS. 10D and 10E) of theattachment anchor245 provides an improved stability in maintaining a cylindrical shape over the embodiment shown inFIG. 10A-10C due to the closed diamond shaped structure or closed configuration formed by thenodes365 and struts370 of the present embodiment in comparison to the series alignment of nodes and struts shown in the embodiment ofFIGS. 10A-10C. All reference numerals correspond to those elements previously or otherwise described.
Attachment Anchor with Barbs
• FIGS. 11A-11D shows another embodiment for theattachment anchor245 of the present invention withbarbs250 joined tonodes365 along an attachment anchor outsideend458. Thenode365 of this embodiment as shown inFIGS. 11B and 11D include thehinge380, thetransition regions410, and thebarb250. Thebarbs250 can be contiguously joined to any portion of anode365 including ahub457 or ahinge380 &455.FIG. 11A shows theattachment anchor245 of this embodiment in a nondeployed state or an insertion state. An isometric view of a portion of theattachment anchor245 shown inFIG. 11A in a nondeployed state is shown inFIG. 11B. Thebarb250 has been folded over into theintranodal opening385 and is being held in a protected conformation by thestruts370 and thetransition regions410.FIG. 11C shows theattachment anchor245 in a deployed or implanted state withbarbs250 extending outward to the side. An isometric view of a portion of theattachment anchor245 shown inFIG. 11C is shown inFIG. 11D. As thestruts370 expanded during the deployment of theattachment anchor245, they released thebarb250 allowing thebarb250 to extend outwards in its fully extended state. Thebarbs250 of thepresent attachment anchor245 are folded and protected when theattachment anchor245 is in a nondeployed state. As the attachment anchor is expanded, thebarbs250 are completely released by thestruts370 such that they extend outward to their fullest extent. This is in contrast to the barbs of other prior art attachment means that are deployed an increasing amount as the attachment means is extended to a greater amount. Thebarbs250 of the present invention are designed to deploy fully and extend outward once theattachment anchor245 has been extended enough such that thestruts370 allow thebarbs250 to be released from its folded position as shown inFIG. 11B. When theattachment anchor245 is expanded by either allowing it to self-expand or through expansion with a dilitation balloon, each of thebarbs250 is released by thestruts370 andtransition regions410 and theintranodal opening385 and allowed to extend outwards. Thebarbs250 provide anchoring of theattachment anchor245 and theintravascular tubular member85 of the present invention or other intravascular stent-graft to the aortic vessel wall or other arterial wall. Such anchoring can help to prevent migration of the intravascular tubular member and help to prevent further aneurysmal dilitation of the aorta. In a nondeployed state thebarbs250 are folded up such that they cannot catch or snag on theintravascular tubular member85 or other intravascular stent-graft device or tissue components. Thebarbs250 can be machined using mechanical, laser, electrochemical, or other machining techniques as described for machining the attachment anchor into the same metal tube that forms theattachment anchor245. Thebarbs250 can be machined such that they are continuous and contiguous with eachnode365 without the need for an attachment of thebarbs250 to thenodes365. Thebarbs250 can be contiguous with thehinges380 or with the hubs454 if such hubs are present on the node. Eachbarb250 is considered to be a component of thenode365. The strength of thebarbs250 is therefore increased and their resistance to stress cracking or fracture will be reduced. Attachment wires or barbs used in other prior art attachment devices have been attached by welding, brazing, or other techniques and have suffered problems with metal failure and fracture of the attachment wires. Thepresent attachment anchor245 does not have such welds, brazes, or other forms of attachment of thebarbs250 to theattachment anchor245.
• FIG. 12A shows theattachment anchor245 attached near theinlet end145 and near theoutlet end148 of anintravascular tubular member85. The intravascular tubular member can be any surgical vascular graft, intravascular tubular member, other intravascular stent-graft, or other vascular tubular member that is in need of anattachment anchor245 to hold either theinlet end145 or theoutlet end148 of the vascular tubular member into contact with a native artery or vein. Theintravascular tubular member85 can be formed from ePTFE, knitted or woven polyester, polyurethane, silicone or any other material use in surgical vascular grafts, intravascular grafts, intravascular stent-grafts, or vascular conduits. Theintravascular tubular member85 can be a straight or bifurcated vascular graft, intravascular graft, or intravascular stent-graft. Theattachment anchor245 holds the intravascular tubular member outward against the native vessel wall, prevents leakage of blood between the vascular tubular member and the native lumen, and prevents distal migration of the vascular tubular member. Theattachment anchor245 can be attached to the intravascular tubular member with securingfibers255. Such securingfibers255 can include sutures, polyester fiber, polytetrafluoroethylene fiber, metal wire, staples, biocompatible and biostable fiber, or other securing means. The securingfibers255 can extend through and attach to any or all of theintranodal openings385 found in thenodes365 of theattachment anchor245. Theattachment anchor245 positioned at theinlet end145 can havebarbs250 attached or theattachment anchor245 can be one withoutbarbs250 as shown on theoutlet end148. If theattachment anchor245 hasbarbs250, the wall of theintravascular tubular member85 or other prior art intravascular stent-graft can be attached to theattachment anchor245 such that thebarbs250 can extend outward without snagging the intravascular tubular member, or other device component such as the delivery sheath225 (seeFIGS. 2C,2D,4C, and4D). If theattachment anchor245 does not havebarbs250 such as theattachment anchor245 positioned, for example, at theoutlet end148, theattachment anchor245 can be attached to the wall of the intravascular tubular member such that it does not protrude beyond theoutlet end148. The securingfibers255 can extend through theintranodal openings385 of theattachment anchor245 without pinching or cutting the securingfibers255.
• FIG. 12B shows theattachment anchor245 attached near theinlet end145 and near theoutlet end148 of the straight intravascular foldedtubular member95. The straight intravascular foldedtubular member95 can be theintravascular tubular member85 shown inFIGS. 2A-2D that can be in need of anattachment anchor245 to hold either theinlet end145 or theoutlet end148 of the straight foldedintravascular tubular member85 into contact with a native artery such as the abdominal aorta or with a vein. Theattachment anchor245 is held to the straight intravascular foldedtubular member95 with securingfibers255 as described inFIG. 12A. Theattachment anchor245 positioned at theinlet end145 can havebarbs250 attached or theattachment anchor245 can be one withoutbarbs250. If theattachment anchor245 hasbarbs250, the straight proximaltubular section wall170 can be attached to theattachment anchor245 such that theattachment anchor245 extends beyond theinlet end145 of the straight intravascular foldedtubular member95 and thebarbs250 can extend outward without snagging the straight intravascular foldedtubular member95. If theattachment anchor245 does not havebarbs250 such as theattachment anchor245 positioned at theoutlet end148, theattachment anchor245 can be attached to the distaltubular section wall190 of the straight intravascular foldedtubular member95 such that it does not protrude beyond theoutlet end148. The securingfibers255 can extend through theintranodal opening385 of theattachment anchor245 without pinching or cutting the securingfiber255.
• FIG. 12C shows theattachment anchor245 attached near theinlet end145 and near each outlet end148 of the bifurcated intravascular foldedtubular member260. The bifurcated intravascular foldedtubular member260 can be the bifurcated intravascular foldedtubular member260 shown inFIG. 5 that is in need of anattachment anchor245 to hold either theinlet end145 or theoutlet end148 of the bifurcated intravascular foldedtubular member260 into contact with a native artery such as the abdominal aorta. Theattachment anchor245 is held to the bifurcated intravascular foldedtubular member260 with securingfibers255 as described inFIG. 12A. It is preferred that theattachment anchor245 positioned at theinlet end145 may havebarbs250 attached although theattachment anchor245 can be one withoutbarbs250. If theattachment anchor245 hasbarbs250, the wall of the bifurcated intravascular foldedtubular member260 can be attached to theattachment anchor245 such that theattachment anchor245 extends beyond theinlet end145 of the bifurcated intravascular foldedtubular member260 and thebarbs250 can extend outward without snagging the bifurcated intravascular foldedtubular member260. If theattachment anchor245 does not havebarbs250 such as shown for eachattachment anchor245 that is positioned at eachoutlet end148, theattachment anchor245 can be attached to the distaltubular section wall190 of the bifurcated intravascular foldedtubular member260 such that it does not protrude beyond theoutlet end148. The securingfibers255 can extend through theintranodal opening385 of theattachment anchor245 without pinching or cutting the securingfibers255.
• The straight intravascular foldedtubular member95 and bifurcated intravascular foldedtubular member260 with theattachment anchor245 shown inFIGS. 12B and 12C have specific advantages that provide these embodiments with distinct advantages when used together. The straight intravascular foldedtubular member95 and bifurcated intravascular foldedtubular member260 can be in need of an attachment means87 that is attached to the intravascular folded tubular member and provides for better attachment than that provided by other prior art attachment means. The straight intravascular foldedtubular member95 and bifurcated intravascular foldedtubular member260 with theattachment anchor245 of the present invention provides theinlet end145 and outlet end148 with a more firm anchoring to the native vessel than with other prior art attachment means. The short nondeployedattachment anchor length400 allows theattachment anchor245 to be placed precisely where it is needed. For example, in the treatment of abdominalaortic aneurysm5 it can be important to place theattachment anchor245 as close as possible to the leftrenal artery45 and rightrenal artery50 where the abdominalaortic wall70 is not distended (seeFIGS. 1A and 1B). Other prior art attachment means with a longer length often can extend into the thrombotic lining of the aorta where it is not possible to provide a firm attachment to the vessel wall. The short deployed attachment anchor length395 (seeFIG. 9C) allows theattachment anchor245 of the present invention to have a greater number ofnodes365 positioned around the circumference to allow for a better attachment to the native vessel. The increased number ofnodes365 offers the opportunity of thepresent attachment anchor245 to have a greater number ofbarbs250 attached. In a nondeployed state, thebarbs250 are protected such that snagging of thebarb250 on the intravascular folded tubular member or delivery sheath225 (seeFIGS. 2C,2D,4C, and4D) is not possible. Upon deployment the increased number ofbarbs250 provides an improved attachment to the vessel wall that can further reduce the chances for further aneurysm dilation and can reduce the chances for distal migration of the intravascular folded tubular member. Once theinlet end145 of the straight intravascular folded tubular member95 (seeFIG. 12B) or bifurcated intravascular foldedtubular member260 is attached to the native vessel proximal to the vessel injury using theattachment anchor245 it is more likely to remain attached without migration as theoutlet end148 of each distaltubular section130 is placed into appropriate location at a site distal to the vessel injury. Placement of theoutlet end148 causes each foldedtubular section125 to unfold and can place a force on theattachment anchor245 at theinlet end145 to move distally. Therefore theattachment anchor245 of the present invention provides the necessary advantages to specifically improve the function of the straight intravascular foldedtubular member95 or bifurcated intravascular foldedtubular member260. Furthermore, since the straight intravascular foldedtubular member95 or bifurcated intravascular foldedtubular member260 is a one-piece construction and not a modular system such as many prior art devices, blood leakage cannot occur except at aninlet end145 oroutlet end148. Placing theattachment anchor245 at theinlet end145 and at each outlet end148 will provide a better seal of the intravascular folded tubular member with the native lumen of the blood vessel. This is due to the increased number of struts370 (seeFIG. 9A) andnodes365 that provide a more uniform force along the circumference of the intravascular folded tubular member. The resulting straight intravascular foldedtubular member95 and bifurcated intravascular foldedtubular member260 will provide a leak free one-piece intravascular folded tubular member that can isolate an aneurysm better than a multi-tubular modular system. Other prior art one-piece systems that cannot provide a positive length determination in situ as with the present intravascular folded tubular member. These prior art one-piece systems require an estimation of their length in comparison to the actual vessel lesion length prior to implant. This often results in placing theinlet end245 oroutlet end148 in a vessel location that is eitherthrombus60 laden, blocks a side branch vessel such as an internaliliac artery80 in the case of abdominal aortic aneurysm repair (seeFIGS. 1A and 1B), or is of inappropriate vessel diameter to match the diameter of the prior art device. The present straight intravascular folded tubular member95 (seeFIG. 12B) or bifurcated intravascular folded tubular member260 (seeFIG. 12C) can have itsinlet end145 and each outlet end148 placed precisely after the intravascular folded tubular member has been delivered within the blood vessel. Theinlet end145 and outlet end148 of the present intravascular folded tubular member can therefore be placed in a vessel location that is better able to form a leak free seal if it is combined with theimproved attachment anchor245 of the present invention.
Wall Structure
• The wall structure for a surgical vascular graft, an intravascular tubular member, an intravascular folded tubular member, or other vascular tubular member, can be formed by weaving fibers or strands of polymeric material, metallic material, or other material to form a woven vasculartubular member460 as shown inFIGS. 13A-13M. The description of these figures and reference to individual components and their reference numerals will proceed together. The woven vasculartubular member460 can have a tight tubular weave that will not leak blood serum or blood cellular elements after implant. Generally one or more circumferential fibers orcircumferential strands465 are woven with a gradual helical wind in a generally circumferential direction470 and a plurality of axial fibers oraxial strands475 are woven in a generallyaxial direction398 and interface or cross over thecircumferential strands465 as shown inFIG. 13A. Theaxial strands475 orcircumferential strands465 can be formed of a single filament or can be formed ofmany filaments483 as shown inFIG. 13B. Following the formation of the woven vasculartubular member460 theaxial strands475 tend to reorient slightly to become perpendicular to the generallycircumferential strands465 and will have a small helical wind to them. In the weave of the strands the points where the generallycircumferential strands465 cross over the generallyaxial strands475 will be referred to as crossover points485 (seeFIG. 13A). The woven vasculartubular member460 can be used as a surgical vascular graft for surgical implant or can be used as anintravascular tubular member85 that can be delivered and implanted percutaneously or delivered through a delivery sheath225 (seeFIG. 4D) placed in a blood vessel that was accessed through a small cutdown procedure to access the blood vessel.
• Polymeric strands used to weave a woven vasculartubular member460 can be formed of asingle monofilament strand490 and are referred to aspolymeric monofilament strands490 or monofilament fibers as shown in the woven monofilament wall structure ofFIG. 13C. A woven vasculartubular member460 formed frompolymeric monofilament strands490 will have small gaps orleakage sites495 for blood leakage at or near the monofilament strand crossover points498. The size of theleakage sites495 is dependent upon themonofilament strand diameter500 as well as how tightly they are packed. The size of the gaps orleakage sites495 can be approximately as large as themonofilament strand diameter500. To prevent blood cellular elements from passing through theleakage sites495, the gaps cannot be significantly larger than the cellular elements found in the blood. Withsmall leakage sites495, red blood cells and platelets can become trapped and create thrombosis that will prevent leakage from that gap or leakage site. Red blood cells are typically 8 micrometers in the larger diameter of the red blood cell.Monofilament strands490 with amonofilament strand diameter500 of only 8 micrometers would be too small, too weak, and impractical to weave or braid into a vascular graft, intravasculartubular member460, or woven vasculartubular member460. Fibers or strands formed from manysmaller filaments483 can form amultifilament strand510 that will provide the necessary sealing at multifilament crossover points513 of amultifilament strands510 in generally theaxial direction398 withmultifilament strands510 in generally the circumferential direction470; these multifilament strands form a woven multifilament strand wall structure shown inFIG. 13B.
• A multifilament strand formed from approximately 3 to 100filaments483 will deform in the crossover points485 and will seal the gaps orleakage sites495 at or near crossover points485 in a weave of themultifilament strands510 as shown inFIG. 13B. Afilament diameter515 can range from approximately 1 to 200 micrometers and themultifilament strand diameter520 or fiber diameter can range from approximately 0.001 to 0.040 inches (seeFIG. 13D). Themultifilament strand510 or fiber will have significant flexibility due to thesmall filament diameter515 and the multifilament strand will have strength due to the presence ofmany filaments483. At the crossover points485 themultifilament strands510 will spread thefilaments483 out to form a more flattened cross section for the strand and this spreading out of thefilaments483 will reduce the size of the gap orleakage site495 such that leakage of blood will not occur as shown inFIG. 13B.
• Polymeric strands can be formed fromfilaments483 of expanded polytetrafluoroethylene (ePTFE), polyester, polyethylene terephthalate, polyurethane, silicone, or copolymers or block copolymers involving these polymers orfilaments483 formed from other polymeric materials that are suitable for implant within the body from the standpoint of biocompatibility, biostability, strength, flexibility, and other properties. An expanded polytetrafluoroethylene filament525 (ePTFE filament525) as shown inFIG. 13E is formed from paste extrusion and can be stretched under high temperature, and sintered at very high sintering temperature to increase the axial strength thereby forming anePTFE filament525 that is well suited to forming an ePTFEmultifilament strand510 that can be woven into the wall structure of the present invention. The wall structure for avascular tubular member83 includes the general material of construction, such as polymeric or metallic, and physical description of the wall such as woven or braided. EachePTFE filament525 can include one or more expanded polytetrafluoroethylene microfilaments530 (ePTFE microfilaments530) within a cross section; such microfilaments tend to contain significant polymeric molecule orientation along its length which contributes to its excellent axial strength. AnePTFE filament525 can containnodal regions535 of polytetrafluoroethylene which can provide sites of junction betweenePTFE microfilaments530 such thatePTFE microfilaments530 are connected together with polytetrafluoroethylene to form asingle ePTFE filament525 that cannot be easily divided intoindividual ePTFE microfilaments530 throughout the length of theePTFE filament525. The expanded polytetrafluoroethylene multifilament strand510 (ePTFE multifilament strand510) for use in weaving surgical vascular grafts, intravasculartubular members85, or other vasculartubular members83 can have a multifilament strand diameter520 (seeFIG. 13D) that ranges from approximately 0.001 to 0.040 inches, an expanded polytetrafluoroethylene filament diameter540 (ePTFE filament diameter540) that ranges from approximately 1-200 micrometers, and an expanded polytetrafluoroethylene microfilament diameter545 (ePTFE microfilament diameter545) that ranges from approximately 0.01 to 200 micrometers. The ePTFEmultifilament strand510 used in larger diameter surgical vascular grafts, intravascular tubular members, or vascular tubular members ranging in diameter from approximately 8 to 30 millimeters such as those used in abdominal aortic aneurysm repair has a preferredmultifilament strand diameter520 that ranges from approximately 0.003 to 0.040 inches, a preferredePTFE filament diameter540 that ranges from approximately 2.5 to 200 micrometers, and a preferred expanded polytetrafluoroethylene microfilament diameter545 (ePTFE microfilament diameter545) that ranges from approximately 0.01 to 200 micrometers. In weaving a surgical vascular graft, intravascular tubular member, or vascular tubular member for coronary or other small diameter vascular applications with a smaller vascular tubular member diameter ranging from approximately a 3 to 6 millimeter diameter, for example, an ePTFEmultifilament strand510 can have a preferredmultifilament strand diameter520 that ranges from 0.001 to 0.020 inches, a preferredePTFE filament diameter540 that ranges from approximately 1 to 200 micrometers, and a preferredePTFE microfilament diameter545 that ranges from approximately 0.01 to 200 micrometers. An ePTFEmultifilament strand510 of the preferred embodiments contains at least threeePTFE filaments525 or at least threeePTFE microfilaments530 in order to provide adequate sealing at multifilament strand crossover points513 and each filament is comprised of one or more microfilaments.
• A surgical vascular graft orvascular implant82,intravascular tubular member85, or vasculartubular member83 formed from weavingmultifilament strands510 of polyester or other polymeric material could have a wall structure for thevascular tubular member83 of the present invention formed frommultifilament strands510 andfilaments483 with diameters having a similar range to that discussed above for the polytetrafluoroethylenemultifilament strands510 andePTFE filaments525.
• Polymericmultifilament strands510 used in forming the woven wall structure of some embodiments of the present invention can extend along theirlinear axis550 with a generally linear or straight shape forming straight multifilament strands555 (seeFIG. 13F). The strands can be formed ofstraight filaments560 that also have a linear or straight shape along theirlinear axis550. Polymericmultifilament strands510 formed from suchstraight filaments560 that are straight will not in general have significant stretch characteristics in the direction of theirlinear axis550. Alternately, polymericmultifilament strands510 can be formed fromcurved filaments570 that have a zig zag shape, a sinusoidal shape, helical shape, or some other form of curved shape extending in the direction of theirlinear axis550 forming a curvedmultifilament strand573 as shown inFIG. 13G. A curvedmultifilament strand573 formed from suchcurved filaments570 will exhibit extension or stretch characteristics in thelinear axis550 direction of the fiber (seeFIG. 13G). The amount of zig zag or curved shape that can be formed into thecurved filaments570 is such that it can provide the curved multifilament fiber or curvedmultifilament strand573 with a stretch amount ranging from approximately one to fifty percent of its length along itslinear axis550. Suchcurved filaments570 can be formed by thermal, chemical, or mechanical treatment of thefilaments483 of the strand to form a set shape found in thecurved filaments570 with at least some temporary memory of the set shape under normal conditions of use for the vascular or intravascular graft. A straight expanded polytetrafluoroethylene filament575 (seeFIG. 13E) containing straight expanded polytetrafluoroethylene microfilaments580 can be exposed to high temperature while fixing or holding a specific length along itsaxis550 to generate a curved shape for the microfilaments as shown inFIG. 13H. This specific length is shorter than its elongated length when exposed to axial stress. This high temperature is lower than the very high temperature used during the sintering step mentioned earlier. This process results in a curved expandedpolytetrafluoroethylene filament585 with curved expandedpolytetrafluoroethylene microfilaments590. The curved shape for thecurved ePTFE microfilaments590 andcurved ePTFE filament585 will not easily return to a straight shape unless exposed to high temperature while held under stress. Expanded polytetrafluoroethylenemultifilament strands510 formed fromcurved ePTFE filaments585 that havecurved ePTFE microfilaments590 will provide significant axial stretch. Thermal treatment can also be applied to polyestermultifilament strands510 or to other polymericmultifilament strands510 to form acurved filaments570 and curvedmultifilament strands573 using techniques known in the textile industry.
• A surgical vascular graft, anintravascular tubular member85, or other vascular tubular member can be formed by weaving ePTFEmultifilament strands510 or other polymericmultifilament strands510 into a tubular form. Themultifilament strands510 can either havestraight ePTFE filaments575 orcurved ePTFE filaments585 and weaving avascular tubular member83 out of curvedmultifilament strands573 will give stretch characteristics in the direction or theirlinear axis550 as they are woven in theaxial direction398, circumferential direction470, or both directions (seeFIGS. 13B and 13G). An embodiment of a vascular tubular member formed from ePTFEmultifilament strands510 ofcurved ePTFE filaments585 is shown inFIG. 13I. Curvedmultifilament strands573 formed fromcurved ePTFE filaments585 could be woven in the circumferential direction470 (seeFIG. 13A) with straightmultifilament strands555 in the axial direction. Such a structure approximates the radial compliance found in native blood vessels and can provide improved healing at the junction sites of the vascular tubular member with the native vessel. Expanded polytetrafluoroethylene curvedmultifilament strands573 can be woven in theaxial direction398 with straightmultifilament strands555 in the circumferential direction470. Such a wall structure can provide improved flexibility with excellent kink resistance. Curvedmultifilament strands573 formed fromcurved ePTFE filaments585 can be woven in each direction to provide a woven vasculartubular member460 with stretch characteristics in both directions (seeFIG. 13I). Such a wall structure can have both radial and axial compliance and be resistant to kinking. Such a woven vasculartubular member460 could be used for standard surgical arterial reconstruction, as a component of a stent-graft, or a the wall structure for and intravascular tubular member for treatment of vascular injury such as abdominal aortic aneurysm repair. A similar vascular tubular member can be woven from straight or curved polymericmultifilament strands510 of polyester or other polymer to form a vascular tubular member similar toFIG. 13I.
• Circumferential strands465 andaxial strands475 formed of metal material can be woven along with the multifilamentpolymeric strands595 formed offilaments483 of polymeric material in the generally circumferential direction470, the generallyaxial direction398, or both directions as shown inFIG. 13J to form the woven vasculartubular member460 shown inFIG. 13A.Metallic strands600 woven along with thepolymeric strands595 can be ametallic monofilament strand490 of a circular cross section or metallicmultifilament strands510 formed from a plurality of smallerdiameter metal filaments483. Themetallic strands600 can be formed out of stainless steel, Nitinol, tantalum, titanium, an alloy of these metals, other metal used in the formation of implanted stents, or other metal capable of being implanted and having adequate strength to support the stresses found in a surgical vascular graft, intravascular graft, or vascular tubular member. Themetallic strands600 can have a generally linear or straight shape in the direction of theirlinear axis550 forming metallicstraight monofilament strands605 or metallic straight multifilament strands555 (seeFIGS. 13K and 13F). In a preferred embodiment themetallic strands600 aremetallic monofilament strands490 and are woven along with the multifilamentpolymeric strands595 to form a wall structure for the woven vasculartubular member460 as shown inFIG. 13J. At the metal to metal crossover points610,leakage sites495 can be created that could allow blood leakage out of the woven vasculartubular member460 formed of the wall structure of this embodiment.
• Alternately, themetallic strands600 can be bent or formed by mechanical, chemical, or thermal methods into a zig zag, sinusoidal, helical, or other curved shape forming a metalliccurved monofilament strand615 or a metallic curvedmultifilament strand570 as shown inFIGS. 13L and 13G. The metalliccurved monofilament strand615 has a direction of itslinear axis550 determined by the overall direction of thecurved monofilament strand615 along its length. The metalliccurved monofilament strand615 is able to extend in a generallylinear axis550 direction by an amount that ranges from one to fifty percent of its generally axial length. The metallicmonofilament strand diameter500 ormultifilament strand diameter520 can range from 0.001 to 0.020 inches. Themetallic monofilament strand490 can provide an outward expansion force to the wall structure of the woven vasculartubular member460 and provide resistance to axial compressive forces generated by the native tissue surrounding the woven vasculartubular member460.
• The wall structure as shown inFIG. 13J for a surgical vascular graft, intravascular graft, an intravascular folded tubular member, or avascular tubular member83 used in the treatment of abdominal aortic aneurysm or the treatment of other large diameter vessels with a diameter of 8 to 30 millimeters, the metallic monofilament strand diameter500 (seeFIG. 13C) is preferably approximately 0.003 to 0.020 inches. For a vascular graft or intravascular graft for treatment or coronary vessels or vessels less than 6 millimeters, the preferred metallicmonofilament strand diameter500 or metallicmultifilament strand diameter520 is approximately 0.001 to 0.016 inches. The presence ofmetallic strands600 in the circumferential direction470 (seeFIG. 13J) provides the surgical vascular graft,intravascular tubular member85, or vasculartubular member83 made from this wall structure with the property of exerting an outward force against the native vessel, holding the native vessel outward in an open and patent conformation, and resisting against vessel contraction due to tissue scarring and healing. Due to the circumferential direction470 of some of themetallic strands600, the amount of outward extensional force generated by ametallic strand600 of smaller diameter is greater than that provided by a larger diameter but more zig zag or bent metallic strands such as those disclosed in prior art stent-graft devices. Themetallic strands600 in theaxial direction398 provide the surgical vascular graft, or intravascular graft formed from this wall structure with resistance to compressive length changes. Theintravascular tubular member85 or vasculartubular member83 as shown inFIGS. 2A,2B,4A,4B, and in other embodiments can have a woven wall structure as described in the embodiments ofFIGS. 13A-13M and can undergo a change in diameter from a smaller or nondeployed diameter305 in its nondeployed state as it is being inserted into the vascular system to a larger or deployeddiameter237 in its deployed state after it is implanted in the appropriate location. The woven vascular tubular member460 (seeFIG. 13A) of the present invention can be formed entirely out of wovenmetallic strands600.
• In a preferred embodiment,metallic strands600 formed of straight605 and curved615 monofilaments of metallic material are woven along with the multifilamentpolymeric strands595 in either theaxial direction398, the circumferential direction470, or both directions as shown inFIG. 13J. Whenmetallic strands600 are woven along with the multifilament polymeric strands in the circumferential direction470 as shown inFIG. 13J, the number of metallic strands per length of woven vasculartubular member460 can range from onemetallic strand600 approximately every 0.060 inches to onemetallic strand600 every 1.5 inches. It is preferred to place ametallic strand600 in the circumferential direction470 approximately every 0.10 to 0.90 inches along the length of the woven vasculartubular member460. For themetallic strands600 in theaxial direction398, the spacing range betweenmetallic strands600 in the circumferential direction470 is the same as the spacing range along theaxial direction398 of the woven vasculartubular member460 with a wall structure as shown inFIG. 13J. This spacing for metallic strands applies to the wall structures which are shown inFIGS. 14,16A-16C,17A-17C,18A, and18B.
• Themetallic strands600 can be formed of a metal with a high yield strength that will remain elastic during the deployment of the intravascular tubular member from the nondeployed state to the deployed state. The high yield strengthmetallic strands600 will provide the intravascular graft with a self-expandable property. Such an intravascular tubular member can be contained completely within a delivery sheath225 (seeFIGS. 2C,2D,4C, and4D) during the delivery of theintravascular tubular member85 to the site of the vessel lesion that is to be treated by the intravascular tubular member. Upon release of the self-expandable intravasculartubular member85 from thedelivery sheath225, it expands outward to its vascular tubular member deployeddiameter237 and the woven wall structure of the present invention is placed into contact with the native vessel or thrombus.
• Alternately, themetallic strands600 shown inFIG. 13J can be formed from a metal with a yield strength that will allow plastic deformation to occur during the deployment of the woven intravasculartubular member460. This embodiment of the woven intravasculartubular member460 formed of this wall structure can be expanded internally by a mechanical expanding means such as a balloon of a balloon dilitation catheter to force theintravascular tubular member85 to expand from its smaller vascular tubular member nondeployed diameter238 to a larger vascular tubular member deployeddiameter237. The metallic strands of this embodiment undergo a plastic deformation during the deployment from the vascular tubular member nondeployed diameter238 to the vascular tubular member deployeddiameter237 as shown inFIGS. 2B,2C,4B, and4D.
• Themetallic strands600 used in the wall structure of the present invention as shown inFIG. 13J can be flattenedmetallic strands620 with approximately a rectangular cross sectional shape (seeFIG. 13M). The advantages of this form of metallic strand is that it provides a closer packing with another flattenedmetallic strands620 at a flattenedcrossover point623 in a weave that contains flattenedmetallic strands620 with a smaller gap andsmaller leakage site495. The flattenedmetallic strands620 can be woven along with multifilamentpolymeric strands595 as shown inFIG. 13J such that minimal blood leakage will occur at crossover points. Flattenedmetallic strands620 can be more difficult to weave than round strands due to required orientation of the flattened strands during weaving.
Woven Wall Structure
• The woven wall structures shown in the embodiments shown in the following figures,FIGS. 14,15,16A-C,17A-C,18A and18B apply to avascular tubular member83 that can be implanted as a surgical vascular graft, as anintravascular tubular member85 without a foldedtubular section125, as an intravascular folded tubular member including a foldedtubular section125, or as any other vascular tubular member. The intravascular tubular member can be a straight intravascular foldedtubular member95, a bifurcated intravascular foldedtubular member260, or a straight intravascular tubular member, without a foldedtubular section125 or a bifurcated intravascular tubular member without a foldedtubular section125. The woven tubular structures of the present invention are intended to be formed without a seam and are therefore seamless. It is further understood that a woven material of the wall structure described in this invention could be formed of a flat woven wall structure that is then formed into a straight or bifurcated tube with a wall structure as described. These figures are intended to represent various combinations ofmultifilament strands510 andmonofilament strands500 of metallic material or polymeric material with a straight or curved conformation used to form the wall structure of the present vasculartubular member83. The actual woven structures showing woven strands of various types is shown inFIGS. 13A-13M. It is further noted that the circumferentially oriented strands actually are woven with a helical wind as discussed earlier. This helical wind can be gradual so that it appears as a generally circumferentially wound strand as shown in these figures. It is understood that thecircumferential strands465 or circumferentially oriented strands can have a significant helical wind to them. This significant helical wind is accomplished by winding more than one strand or several strands in the circumferential direction470 at the same time. An even greater helical wind can be accomplished in the circumferential direction by generating a double helical wind with each helix involving several strands. A double helix can be formed, for example by introducing circumferential strands into the tubular weave from two positions located 180 degrees apart. Axial strands tend to orient themselves such that they are perpendicular to the circumferentially oriented strands giving the axial strands a helical wind or turn to them.
• The present invention for avascular tubular member83 includes the wall structure for the vascular tubular member. The woven wall structures shown inFIGS. 14,16A-16C,17A-17C,18A,18B,20A-20D,21,22A,22B, and23 are included in the preferred embodiments of this invention. The strands that are of a polymeric material used to form these wall structures are woven with onlymultifilament strands510 of polymer material. Polymer material can be any of the polymers indicated including ePTFE, polyester, or other suitable polymer material. Themultifilament strands510 can be woven in either a generallyaxial direction398 or a generally circumferential direction470. These multifilament strands of polymeric material can be formed offilaments483 that are either curved filaments or straight filaments; and hence themultifilament strands510 of polymeric material will be referred to as curved axialpolymeric strands625, curved circumferentialpolymeric strands630, straight axialpolymeric strands635, and straight circumferentialpolymeric strands640. The present invention for avascular tubular member83 includes a wall structure that can be formed from wovenmetallic strands600. Themetallic strands600 can bemetallic monofilament strands490 or metallicmultifilament strands510. In the preferred embodiments of the above indicated figures,FIGS. 14,16A-16C,17A-17C,18A,18B,19,20A-20D,21,22A,22B, and23, the metallic strands aremetallic monofilament strands490 woven along with themultifilament strands510 of polymeric material in either theaxial direction398, circumferential direction470, or both directions formingmonofilament strands490 of metallic material. Themonofilament strands490 of metallic material can be formed ofstraight monofilament strands605 orcurved monofilament strands615 and hence themonofilament strands490 of metallic material will be referred to as curved axialmetallic strands645, curved circumferentialmetallic strands650, straight axialmetallic strands655, and straight circumferentialmetallic strands660.
• The wall structures described inFIGS. 14,16A-16C,17A-17C,18A,18B, and19 can all be applied as avascular tubular member83 that is suitable for vascular surgery, as anintravascular tubular member85 that is suitable for intravascular implant either with percutaneous access or with a small surgical cutdown in an adjoining vessel either proximal or distal to the site of vascular injury. As anintravascular tubular member85, it can be used without an attachment means as shown in these drawings, or it can be used with any attachment means found in the prior art, or with theattachment anchor245 disclosed earlier in this disclosure as a part of this invention. The wall structures can be formed into a straight intravascular foldedtubular member95, or a bifurcated intravascular foldedtubular member260 as shown inFIGS. 2A,2B,4A, and4B. Each vascular tubular member presented has aninlet end145, anoutlet end148, aninner surface135, anouter surface140, a vasculartubular member wall662, and awall thickness663.
• FIG. 14 shows an embodiment for the wall structure for the surgical vascular graft, theintravascular tubular member85, or thevascular tubular member83 of this invention. All reference numerals correspond to those elements previously or otherwise described. This structure has straight axialmetallic strand655 and straight circumferentialmetallic strands660 woven along with straight axialpolymeric strands635 and straight circumferentialpolymeric strands640. The straight axialpolymeric strands635 or straight circumferentialpolymeric strands640 tend to seal polymer to polymer crossover points665 between these strands and can effectively seal polymer to metal crossover points670 such as between a straight axialpolymeric strand635 with a straight circumferentialmetallic strand660. The straight circumferentialmetallic strands660 provide outward force of this tubular member against the aortic wall in it deployed state. The straight circumferentialmetallic strands660 help to resist kinking by helping to maintain a round cross section. The straight axialmetallic strands655 provide the tubular member with strength in theaxial direction398 to overcome compressive forces that may act to reduce its axial length. The straight axialmetallic strands655 enhance the ability of the foldedtubular section125 of a straight95 or bifurcated260 intravascular folded tubular member to unfold easily without wrinkling of the folded tubularsection center wall160. The presence of the straight axialmetallic strands655 generates axial stiffness in the tubular member causing it to be less flexible in negotiating tortuous turns found in the iliac, femoral, and other arteries of the body.
• FIGS. 14 and 13J show a metal tometal crossover point610 of a straight circumferentialmetallic strand660 with a straight axialmetallic strand655.FIGS. 14 and 13J will be used as an example to describe the process of forming a double weave. It is understood that the double weave can be equally well applied to any wall structure that involves ametallic strand600 crossing over anothermetallic strand600. To prevent leakage from occurring at gaps orleakage sites495 of such metal to metal crossover points610 a tubular double weave is created as shown inFIG. 15. For example, in theaxial direction398 both the straight axialpolymeric strands635 and the straight axialmetallic strands655 are woven together in theweave plane675 to the left of the metal tometal crossover point610. Near the metal tometal crossover point610 the straight axialmetallic strands655 are brought out of theweave plane675 and above the straight circumferentialmetallic strand660 and back into theweave plane675 to the right of the metal tometal crossover point610. Underneath the straight axialmetallic strands655 at the crossover point the straight axialpolymeric strands635 are woven with the straight circumferentialpolymeric strands640 and the straight circumferentialmetallic strand660 such that a continuous wovenlayer680 is located beneath the straight axialmetallic strand655 that was brought out of theweave plane675. The result is a leak free wall structure with metallic strands being woven in two directions,axial direction398 and circumferential direction470.
• FIG. 16A shows another embodiment for the wall structure of the present invention. In this embodiment straight circumferentialpolymeric strands640 and straight circumferentialmetallic strands660 are woven circumferentially and only straight axialpolymeric strands635 are woven axially. This embodiment does not have the axial compressive force capability described in the embodiment ofFIG. 14 but it has excellent kink resistance due to the straight circumferentialmetallic strands660 and has excellent flexibility through tortuous turns since only the flexible polymeric strands are positioned axially.
• FIG. 16B shows still another vascular tubular member wall structure with a curved axialmetallic strand645 woven along with a straight axialpolymeric strand635 in theaxial direction398 instead of the straight axialmetallic strand655 as shown inFIG. 14. The curved axialmetallic strand645 also provides the vascular graft, the intravascular graft, or the tubular member with good axial support against compressive forces generated by thethrombus60 and other physiological forces that can be placed upon the tubular member. The curved axialmetallic strand645 can compress elastically and thereby will provide this tubular member wall structure with good axial flexibility to extend around tortuous turns in a blood vessel. The curved axialmetallic strand645 provides a benefit to the foldedtubular section125 of a straight intravascular foldedtubular member95 or bifurcated intravascular foldedtubular member260 by resisting wrinkling during the unfolding process. The curved axialmetallic strand645 can prevent the center wall of the foldedtubular section125 from forming wrinkles (seeFIG. 7E) and can help the intravascular foldedtubular section125 to unfold evenly during the deployment of the folded tubular member.
• FIG. 16C shows yet another wall structure for the surgical vascular graft,intravascular tubular member85, or vasculartubular member83 having a similar structure to that ofFIG. 16B only with a curved circumferentialmetallic strand650 in the circumferential direction instead of the straight circumferentialmetallic strand660. Theaxial strands475 have remained the same as inFIG. 16B. The curved circumferentialmetallic strand650 found in this structure allows the foldedtubular section125 of a straight intravascular foldedtubular member95 or bifurcated intravascular foldedtubular member260 to unfold with greater ease due to their ability to elongate diametrically as one curved circumferentialmetallic strand650 located in an folded tubular sectioninner wall165 or folded tubular sectionouter wall155 passes adjacent to another curved circumferentialmetallic strand650 located in the folded tubularsection center wall160. The curves or bends in the curved circumferentialmetallic strands650 also allows the intravascular folded tubular member to expand out uniformly to its deployeddiameter237 and provide uniform contact with the wall or the native vessel or aortic wall in the case of abdominal aortic aneurysm. The deployeddiameter237 of thevascular tubular member83 used as an intravascular tubular member85 (seeFIG. 1B) of the present invention can be smaller than the equilibrium diameter that the intravascular tubular member could attain if not constrained by the native vessel in the deployed state.
• FIG. 17A shows one more vasculartubular member83 wall structure with a curved circumferentialpolymeric strand630 woven along with a straight circumferentialmetallic strand660 in the circumferential direction and a straight axialpolymeric strand635 is woven along with a curved axialmetallic strand645 in theaxial direction398. The curved circumferentialpolymeric strand630 provides an amount of circumferential stretch in the diametric direction. The straight circumferentialmetallic strands660 and curved axialmetallic strands645 restrict excessive circumferential stretch of the curved circumferentialpolymeric strands630. This wall structure can also be modified slightly to provide an additional characteristic. Near theinlet portion685 of the tubular means the straight circumferentialmetallic strand660 can be eliminated thereby allowing the vascular tubular member to expand to a larger circumference. This circumferential expansion allows the vascular tubular member of the present invention to accommodate a reasonable tolerance in the estimated diameter of the artery such as an estimation of the diameter of the aortic neck. Theinlet end145 of thevascular tubular member83 can accommodate a tolerance in the estimation of the aortic neck diameter and provide a leak free seal of the vascular tubular member with the vessel wall without overlap of excess material at theinlet end145 oroutlet end148 due to an oversized diameter of thevascular tubular member83. Similar circumferential accommodation also applies to accommodating the estimated diameter of an artery or blood vessel such as the iliac or femoral artery with theoutlet end148 of thevascular tubular member83.
• Accommodation of the estimated aortic diameter or other blood vessel diameter with avascular tubular member83 of a fixed non-flexible wall material in the circumferential direction470 with a maximum diameter can also be accomplished by ensuring that the vascular tubular member chosen can expand to a larger maximum deployeddiameter237 than the arterial diameter in which the device is to be placed. For the abdominal aortic aneurysm application this is accomplished by choosing avascular tubular member83 with an equilibrium diameter or maximum dimension of the deployeddiameter237 that is larger than the aortic diameter plus any tolerance in diameter estimation associated with measuring technique errors. Any excess intravascular tubular member wall material due to a slight oversized tubular member diameter will result in an overlap of excess wall material. Provided that this overlap material is held tightly against the aortic wall by the proximal attachment means87, leakage at the proximal site will not occur.
• FIG. 17B shows yet one more vascular tubular member wall structure which is the same as that ofFIG. 17A except that a curved circumferentialmetallic strand650 has replaced the straight circumferentialmetallic strand660. This structure offers the ability to stretch in the circumferential direction470 to a limited extent controlled by the amount of curvature provided to the curved circumferentialmetallic strands650 and curved circumferentialpolymeric strands630. This vasculartubular member83 wall structure provides good anti-kink characteristics, good axial support against compression, good flexibility, and will accommodate a reasonable tolerance in the diameter of the proximal aortic neck, and a tolerance on the iliac artery diameter.
• FIG. 17C shows still one more vascular tubular member wall structure with a curved circumferentialpolymeric strand630, a curved circumferentialmetallic strand650, a curved axialpolymeric strand625 interwoven, and a curved axialmetallic strand645. This structure offers the ability to stretch in the circumferential direction470 andaxial direction398 to a limited extent controlled by the amount of curvature provided to the strands. This structure can extend throughout the entire tubular means. This vascular tubular member wall structure provides good anti-kink characteristics, good axial support against compression, good flexibility, and will accommodate a reasonable tolerance in the aortic neck diameter, and a tolerance on the iliac artery diameter.
• FIGS. 18A and 18B show further embodiments of the wall structure that can be applied to thevascular tubular member83 of the present invention. The vascular tubular member wall structures presented inFIGS. 14,16A-16C,17A-17C that contain curved axialmetallic strands645 or straight axialmetallic strands655 which can be directed with an augmented amount of helical turn. This augmented helical turn is accomplished by taking the straight axialmetallic strands655 out of theweave plane675, creating a step-over690 by stepping the straight axialmetallic strands655 over to a new site that is displaced circumferentially, and inserting thestrands655 back into the plane of theweave675 as shown inFIG. 18A. This stepping over process allows the axialmetallic strand655 to assume a helical pathway along theaxial direction398 of thevascular tubular member83. This augmented amount of helical turn is in addition to the gradual helical turn naturally found in the axially orientedmetallic strands600 due to their natural desire to orient perpendicular to the generallycircumferential strands465 such as the straight circumferentialmetallic strands660 and curved circumferentialpolymeric strands630 which also have a slight helical turn since they are wound in a continuous helix as shown inFIG. 18A. The augmented helical turn of the metallic strand in the generallyaxial direction398 provides the stent-graft with an ability to bend without kinking even when straight metallic strands are used in theaxial direction398. InFIG. 18B two straight circumferentialmetallic strands660 are wound in a double helix with a greater angle with respect to the circumference. This induces the curved axialmetallic strands645 to orient at an angle with respect to the axial direction480.
• In the embodiments of the wall structure of the present invention shown inFIGS. 18A and 18B curved circumferentialpolymeric strands630 and curved axialpolymeric strands625 are wound in the circumferential470 andaxial direction398 to provide thevascular tubular member83 with a supple feel and good bending characteristics without kinking. For simplicity of manufacturing, a straight circumferentialmetallic strand660 is wound in the circumferential direction470. Either a curved axial metallic strand645 (seeFIG. 18B) or a straight axial metallic strand655 (seeFIG. 18A) with the step over characteristic described above is used in theaxial direction398 to provide the necessary compressive strength as well as provide good flexibility to thevascular tubular member83.
• An entire straight vascular tubular member or bifurcated vascular tubular member can be formed from a single contiguous woven material comprised of the polymericmultifilament strands510 or the combined polymericmultifilament strands510 andmetallic monofilament strands490 described inFIGS. 14,16A-16C,17A-17C,18A, and18B. The bifurcated intravascular foldedtubular member260 can be woven without seam in its proximal tubular section, foldedtubular section125, or distaltubular section130. This is accomplished by weaving themain trunk270 with approximately twice the number of polymericmultifilament strands510 andmetallic monofilament strands490 in the axial398 and circumferential470 directions as will be used in eachproximal leg tube275, foldedtubular section125, or distal tubular section130 (seeFIGS. 13J and 14). The weaving of twoproximal leg tubes275 from themain trunk270 can proceed continuously without seam as approximately half of the strands in theaxial direction398 and circumferential direction470 are directed from themain trunk270 to each proximal leg tube. Theweave plane675 for each proximal leg tube275 (seeFIG. 4A) is continued to form theweave plane675 for the wall structure for the foldedtubular section125 and the distaltubular section130. Thewall thickness663 of the woven vascular tubular member460 (seeFIG. 13A) can be formed tominimal wall thickness663 while maintaining strength of the vasculartubular member wall662.
Braided Wall Structure
• FIG. 19 shows a wall structure of the braided vasculartubular member705 of the present invention formed from a braiding process with similar nomenclature being used as used for the woven vasculartubular member460. The braided vasculartubular member705 has straight polymeric and straight metallic strands braided in a right hand spiral forming a straight rightspiral polymeric strand710 and a straight right spiralmetallic strand715, and in a left hand spiral forming a straight left spiralpolymeric strand720 and a straight left spiralmetallic strand725. The braiding process provides some ability for this wall structure to accommodate reasonable tolerances in the estimation of the proximal aortic neck diameter in order to provide a good diametric fit between the braided vasculartubular member705 and the proximal aortic neck. Thestrands710,715,720, and725 can be made with localized bends or curves in them as described earlier, and these strands can be braided as described for the embodiments ofFIGS. 14,16A-16C,17A-17C,18A, and18B, and these stands can be braided as described inFIG. 19. The presence of the straight or curvedmetallic monofilament strands605 and615 (seeFIGS. 13L and 13K) provides good axial and circumferential strength and stability against compression in the radial oraxial direction398. The metalliccurved monofilament strands615 or curved polymericmultifilament strands573 can provide the vascular tubular member with a greater flexibility due to the ability of these strands to compress or extend as the braided vasculartubular member705 is exposed to a tortuous pathway. The spacing between the right spiralmetallic strands715 or the left spiralmetallic strands725 braided in either the right or left spiral to form a braided vasculartubular member705 is similar to the spacing ranges stated for the woven vasculartubular member460.
Applications of Wall Structure
• The wall structure described inFIGS. 13A-13M,14,15,16A-16C,17A-17C,18A,18B, and19 can be applied to a surgical vascular graft, anintravascular tubular member85, or other vasculartubular member83. As a surgical vascular graft with a woven or braided wall structure, themetallic straight605 and curved615 monofilament strands offer improved kink resistance and can provide crush resistance to the vascular graft when placing the graft across a knee joint or other vascular space that is exposed to compressive forces. For the woven vasculartubular member460 the curved circumferentialpolymeric strands630 and curved circumferentialmetallic strands650 offer enhanced diametric flexibility or diametric compliance which can lead to improved healing at anastomoses of the vascular tubular member with the native vessel. The curved axialmetallic strands645 or straight axialmetallic strands655 of the woven tubular member offer resistance to axial compressive forces which can also lead to kinking and allow the vascular graft to be pulled through tunnels during implantation without concern for damage to the vascular graft due to excessive axial stretching. As an intravascular tubular member the woven and braided wall structures offer the benefit of a built-in stent. For the woven vasculartubular member460 the straight circumferentialmetallic strands660 and curved circumferentialmetallic strands650 offer a thin wall structure with excellent expansion elastic forces acting outward against the native vessel wall or native lumen. Since the straight660 and curved650 circumferential metallic strands can be positioned regularly within the wall structure throughout the weave, there can be more of them and their diameter can be smaller than stent wires for most prior art stents. For the woven vasculartubular members460 the straight660 and curved650 circumferential metallic strands are nearly circumferential; they exert a greater outward force for a thinner strand diameter than a zig zag shaped stent or as stent with large bends that require theirstruts370 to extend in a non-circumferential direction. The straight655 and curved645 axial metallic strands of the woven vasculartubular members460 also provide a built-in structure onto which any attachment means can be attached firmly to either theinlet145 oroutlet end148. The woven wall structures with curved circumferentialmetallic strands650 and curved circumferentialpolymeric strands630 are able to stretch circumferentially and accommodate errors in estimated diameter of the native blood vessel. The woven wall structures with curved circumferentialpolymeric strands630 along with straight or curved circumferentialmetallic strands650 can also accommodate errors in the estimation of native vessel diameter by removing the straight660 or curved650 circumferential metallic strands near theinlet end145 or theoutlet end148 of the intravascular tubular member. The curved circumferentialpolymeric strands630 of the woven wall structure will allow theintravascular tubular member85 to stretch and accommodate errors in the diameter estimation such that any attachment means87 placed at theinlet end145 or outlet end148 can form a leak tight seal with the artery either proximal or distal to the vessel injury. The woven460 or braided705 vascular tubular member formed from polymericmultifilament strands510 can also be used as anintravascular tubular member85 and offers the strongest and safest wall structure for thethinnest wall thickness663. The safety associated with weaving or braidingmultifilament strands510 of ePTFE relates to its ability to avoid a catastrophic tear in the wall structure. Standard tubular ePTFE vascular grafts can form an axial or circumferential tear that can lead to significant complications or possibly patient death. The woven vasculartubular member460 formed frommultifilament strands510 of ePTFE would not allow a local defect found in the wall structure to extend in anaxial direction398 or circumferential direction470. The multifilament strands allows the woven vasculartubular member460 formed from the strands containingePTFE filaments525 to seal against blood leakage atcrossover points485 of the ePTFE strands.
• The wall structure described inFIGS. 13A-13E,14,15,16A-16C,17A-17C,18A, and18B are well suited to the straight intravascular foldedtubular member95 and bifurcated intravascular foldedtubular member260 with associated advantages. The woven wall structure, woven from polymericmultifilament strands510 in one embodiment and in other embodiments with metallic straight605 or curved615 monofilament strands also woven along with the polymericmultifilament strands510, offers the greatest strength with one of the thinnest wall thicknesses663. Since the foldedtubular section125 of the straight intravascular foldedtubular member95 or bifurcated intravascular foldedtubular member260 has three foldedtubular section walls330, it is important that each wall be of aminimum wall thickness663. Also of importance is ensuring that the straight or bifurcated proximaltubular section wall170, foldedtubular section walls330, and distaltubular section wall190 cannot be easily torn which can lead to a life threatening sequalae for the patient. These safety and performance characteristics can be obtained by weavingmultifilament strands510 of ePTFE ormultifilament strands510 of polyester as described inFIGS. 13A-13M. The foldedtubular section125 requires that the folded tubular sectioninner wall165, folded tubular sectionouter wall155, and folded tubularsection center wall160 can slide with respect to each other as the straight intravascular foldedtubular member95 or bifurcated intravascular foldedtubular member260 is deployed from a partially deployed state of smaller length to a fully deployed state of greater length. The woven wall structures with straight circumferentialmetallic strands660 or curved circumferentialmetallic strands650 provide a substantially smooth wall structure without significant protrusions that can provide ease of unfolding in the foldedtubular section125. The weaving of metallic straight605 or curved615 monofilament strands in the circumferential direction470 into the wall structure provides an optimum way of providing a built-in metallic stent to provide outward expansion forces while minimizing the thickness of the three foldedtubular section walls330. Since the metallic straight605 or curved615 monofilament strands are acting in a nearly circumferential direction470, their strength to provide the outward expansion forces is greatest for the leastmetallic strand600 diameter.
• FIG. 20 shows theinlet end145 and outlet end148 of anintravascular tubular member85 with a wall structure similar to an embodiment shown inFIG. 14,16A-16C,17A-17C,18A, or18B. The woven wall structure can be formed of any combination of weave involving either straight multifilament strands, straight monofilament strands, curved multifilament strands, or curved monofilament strands used to weave generally circumferentialpolymeric strands740, generally circumferentialmetallic strands745, generally axialpolymeric strands750, and generally axialmetallic strands755 as described in the previous embodiments or otherwise intended. Thus for example, a generally circumferentialpolymeric strand740 is understood to mean a straight640 or curved630 circumferential polymeric strand, a generally circumferentialmetallic strand745 means a straight660 or curved650 circumferential metallic strand, a generally axialpolymeric strand750 means a straight635 or a curved625 axial polymeric strand, and a generally axialmetallic strand755 means a straight655 or a curved645 axial metallic strand. This definition shall also be applicable toFIGS. 21-23. Attached to theinlet end145 is an attachment means87. The attachment means can be theattachment anchor245 described inFIGS. 9A,9B,10A-10C, and11A-11D. A displacedattachment anchor760 is located at a position displaced away from theinlet end145 in a proximal direction and not in contact with the woven wall structure. The displacedattachment anchor760 is theattachment anchor245 that is located away from theinlet end145. The distance that the displaced attachment anchor is located from theinlet end145 can range from approximately 5 millimeters to 40 millimeters. For an abdominal aortic aneurysm application the displacedattachment anchor760 can be displaced approximately 10 to 25 millimeters away from theinlet end145. The displaced anchor is attached to the intravascular tubular member with axially orientedattachment strands765. Theattachment strands765 can be attached to the displacedattachment anchor760 through selected intranodal openings385 (seeFIG. 9A) of the displacedattachment anchor760. Theattachment strands765 can be extensions of the generally axialmetallic strands755 or generally axialpolymeric strands750. Preferably theattachment strands765 are generally axialmetallic strands755 which are continuous with the generally axialmetallic strands755 found in the weave of theintravascular tubular member85. Thus, the woven wall structure of theintravascular tubular member85 with generally axialmetallic strands755 has the structure inherent in the woven intravascular tubular member to simply extend some or all of the generally axialmetallic strands755 proximally beyond theinlet end145 and use them to attach to the displacedattachment anchor760. The displacedattachment anchor760 provides a proximal anchoring site that is positioned farther away proximally from the vessel injury than theinlet end145. Vessel side branches such as the leftrenal artery45 and rightrenal artery50 in the case of abdominal aortic aneurysm that can extend from the aorta adjacent and proximal to theinlet end145 of theintravascular tubular member85 are able to receive blood flow from the native vessel between theinlet end145 or the intravascular tubular member and the displacedattachment anchor760. In the case of treating abdominal aortic aneurysm the right and leftrenal arteries45 &50 can be located between the displacedattachment anchor760 and theinlet end145 of the vascular tubular member. Only a minimal number ofattachment strands765 are needed to attach the displacedattachment anchor760 to theinlet end145 of the tubular member, ranging from two to approximately sixteen. Preferably the number ofattachment strands765 ranges from approximately three to six. The likelihood of an attachment strand crossing over a vessel side branch is reduced with a smaller number ofattachment strands765. Asingle attachment strand765 extending from a generally axialmetallic strand755 that crosses over an inlet to a vessel branch will not significantly affect the flow rate of blood to that side branch vessel. The displacedattachment anchor760 can havebarbs250 to help provide a more firm attachment to the vessel wall such as the vessel wall of the aorta. Either the displacedanchor760 or theattachment anchor245 attached at or near theinlet end145 of the tubular member can havebarbs250 or can be provided withoutbarbs250.
• Theattachment anchor245 positioned at theinlet end145 or outlet end148 of the intravascular tubular member can also be efficiently attached to any generally axialmetallic strands755 or generally axialpolymeric strands750 of the wall structure described inFIG. 14,16A-16C,17A-17C,18A,18B, or20. Preferably theattachment anchor245 is attached to a plurality of generally axialmetallic strands755 that can form a firm attachment to theattachment anchor245. The general axialmetallic strands755 can efficiently attach to theattachment anchor245 using theintranodal openings385 as sites for attachment. A generally circumferentialmetallic strand745 near theinlet end145 or outlet end148 of the vascular tubular member can be removed to provide theintravascular tubular member85 formed with curved circumferentialpolymeric strands630 with stretchability with an ability to accommodate error in the estimated diameter of the native vessel as was discussed inFIG. 17A. This wall structure allows theinlet end145 or outlet end148 to stretch and enlarge in diameter by up to approximately fifty percent and provide a better diametrical fit to the native vessel without leakage. Theattachment anchor245 attached to thestretchable inlet end145 or outlet end148 of the intravascular tubular member can make a tighter seal with the native vessel wall without requiring overlap of the wall structure near theinlet end145 or outlet end148 between theattachment anchor245 and the native vessel wall or native lumen. The braided wall structure of the vascular tubular member shown inFIG. 19 can also be used with the displacedattachment anchor760. A plurality of right spiralmetallic strands715 or left spiralmetallic strands725 can be extended proximally beyond theinlet end145 and attached to the displacedattachment anchor760 in a manner similar to that described for the woven vasculartubular member460.
• FIG. 21 shows avascular tubular member83 with a foldedtubular section125 and with a woven wall structure as described inFIGS. 14,16A-16C,17A-17C,18A, and18B. The woven wall structure can be formed from generally circumferentialmetallic strands745, generally circumferentialpolymeric strands740, generally axialmetallic strands755 and generally axialpolymeric strands750 that have been defined in the description ofFIG. 20. The woven structure containingmetallic monofilament strands490 and polymericmultifilament strands510 is well suited to forming the foldedtubular section125 of the straight intravascular foldedtubular member95 or the bifurcated intravascular foldedtubular member260. The foldedtubular section125 can be formed with a minimaltriple wall thickness770 for the foldedtubular section walls330 due to the wall structure of the present invention. Having the generally axialmetallic strands755 and generally circumferentialmetallic strands745 woven into the wall provides the present invention with the advantage that a greater number of smaller thicknessmetallic strands600 can be used to provide the outward force generated by the generally circumferentialmetallic strands745. Also the generally circumferentialmetallic strands745 and generally axialmetallic strands755 do not require an additional binding means to bind them to thevascular tubular member83 as required by other prior art devices. Providing the general circumferentialmetallic strands745 as part of the weave also allows the foldedtubular section125 to unfold smoothly and evenly without catching or snagging such as on a protruding metal wire or stents attached to the outside of the walls of other prior art stent-graft devices. The woven wall structure of the present invention will allow the foldedtubular section125 to unfold with a steady uniform force as the intravascular folded tubular member extends in length from a partially deployed state to a deployed state. It is understood that the woven structure described in this invention can be applied to straight intravascular foldedtubular member95 or bifurcated intravascular foldedtubular member260. In addition, the woven structure can be applied to the straight intravascular foldedtubular member95 or the bifurcated intravascular foldedtubular member260 that do not contain a foldedtubular section125 and are intended for intravascular use. Also, the woven wall structure can be applied to straight or bifurcated vasculartubular members83 that can be used for standard surgical implant for treatment of vascular injuries. The straight95 or bifurcated260 intravascular folded tubular member is also well suited to be formed entirely from only generally circumferentialpolymeric strands740 and generally axialpolymeric strands750 as shown inFIG. 22. Thethin wall thickness663 provides the foldedtubular section walls330 with a thin overall wall thickness for the three walls. The smooth wall structure formed from the woven polymericmultifilament strands510 will allow for smooth and uniform unfolding of the foldedtubular section125 without binding as it unfolds during deployment to a fully deployed state. All reference numerals correspond to those elements previously or otherwise described. The woven vasculartubular member460 shown inFIGS. 14,16A-C,17A-C,18A, and18B are well suited to forming a straight95 or bifurcated260 intravascular folded tubular member. In placing theoutlet end148 in its appropriate position it is important that the woven vasculartubular member460 does not reduce in diameter as theoutlet end148 is being placed and the foldedtubular section125 is unfolding. The woven vasculartubular member460 does not reduce in diameter if it is pulled from each end in tension. The woven vasculartubular member460 does not reduce in diameter when used as a straight95 or bifurcated260 intravascular folded tubular member that is being extended in length and forms a fully deployed state. The presence of straight660 or curved650 circumferential metallic strands further helps to maintain the deployeddiameter237 at a constant value without necking down or reducing in diameter in extending to a fully deployed state. The woven wall structure is also well suited to the straight95 or bifurcated260 intravascular folded tubular member because theaxial strands475 provide a significant resistance to axial length change in the material itself. Thus during deployment from a partially deployed state to a fully deployed state the extension to a deployed tubular member length will occur primarily due to the unfolding of the foldedtubular section125.
• FIG. 23 shows a bifurcated intravascular foldedtubular member260 formed with a woven wall structure. The woven wall structure can be formed from generally circumferentialmetallic strands745, generally circumferentialpolymeric strands740, generally axialmetallic strands755 and generally axialpolymeric strands750 that have been defined in the description ofFIG. 20. The foldedtubular sections125 are formed from the woven wall structure. Theinlet end145 has anattachment anchor245 attached, theattachment anchor245 havingbarbs250. Eachoutlet end148 has anattachment anchor245 attached, eachattachment anchor245 at theoutlet end148 being withoutbarbs250. As shown inFIG. 23, this bifurcated intravascular foldedtubular member260 is intended as anintravascular tubular member85 that is delivered to the site of a vascular injury through a proximal or distal vessel adjacent to and connecting to the injured vessel. One common application for this intravascular tubular member is for the treatment of abdominal aortic aneurysm. For this application, the tubular member is generally delivered through a smaller diameter delivery sheath225 (seeFIG. 4C) that is capable of being introduced into one of the commonfemoral arteries30. Typically, a small surgical cutdown may be required to access the femoral artery and provide access for adelivery sheath225 through which the bifurcated intravascular foldedtubular member260 is delivered. The commonfemoral artery30 which provides the main access for theintravascular tubular member85 including the access for theinlet end145 of theintravascular tubular member85 will be referred to as the ipsilateral artery or the ipsilateral side. Theintravascular tubular member85 is delivered to the injury site in a nondeployed state, with a smaller bifurcated nondeployed inlet end diameter230 and nondeployedoutlet end diameter235, and a shorter bifurcated nondeployed tubular member length280 (seeFIG. 4B). The bifurcated intravascular foldedtubular member260 is preferred to have anattachment anchor245 at theinlet end145 of the intravascular tubular member to ensure a tight and leak free fit with the aorta in a deployed state although theattachment anchor245 is not required of the present invention. It is understood that the bifurcated intravascular foldedtubular member260 can have generally circumferentialmetallic strands745 woven within the wall structure of the tubular member. Therefore, it is not a requirement that the bifurcated intravascular foldedtubular member260 of the present invention have anattachment anchor245 at theinlet end145 or at theoutlet end148. It is preferred to have anattachment anchor245 at theinlet end145 to better and more firmly attach the intravascular folded tubular member to the blood vessel wall proximal to the vessel injury without blood leakage at that site or migration of the intravascular folded tubular member. The bifurcated intravascular foldedtubular member260 can be a self-expandable tubular member that is contained within the smaller diameter tubular delivery sheath225 (see.FIGS. 4C and 4D) for delivery and assist in deployment. Upon removal of the intravascular tubular member from thedelivery sheath225, the bifurcated intravascular foldedtubular member260 and eachattachment anchor245 is capable of expanding outward and can exert an outward force against the aortic or other arterial wall. The bifurcated intravascular foldedtubular member260 can also be a balloon-expandable tubular member that can be delivered to the site of vessel injury mounted on a balloon catheter. Either the foldedtubular member125, eachattachment anchor245, or both the foldedtubular member125 and the attachment anchors245 can require expansion from a dilitation balloon to force them outward and into close approximation with the aorta, the wall of the native lumen, or to a radially deployedinlet end diameter105 and deployedattachment anchor diameter320. Whether the intravascular tubular member andattachment anchor245 are self-expandable or balloon-expandable, theattachment anchor245 located at theinlet end145 of the tubular member is carefully placed such that it is positioned adjacent and just distal to the renal arteries or within the proximalaortic neck90 prior to deployment (seeFIG. 1B). For treatment of abdominal aortic aneurysm the short axial length of theattachment anchor245, along with the understanding that theattachment anchor245 is formed of a metal such as tantalum or contains metal that can be easily visualized under fluoroscopy, allows theattachment anchor245 to be positioned accurately and close to the renal arteries.Barbs250 can be located on theattachment anchor245 to ensure that theattachment anchor245 is well seated into the aorta and cannot migrate distally although they are not required for all embodiments of this invention. It is further understood that a displacedattachment anchor760 can also be located proximal to the renal arteries and attached to the bifurcated intravascular foldedtubular member260 usingattachment strands765 as described earlier.
• After theinlet end145 of the bifurcated intravascular foldedtubular member260 has been deployed and attached to the aorta for the case of abdominal aortic aneurysm repair with theattachment anchor245, each outlet end148 of the tubular member is moved into its appropriate location within the iliac20 &25 or femoral30 artery. As the outlet ends148 of the bifurcated tubular member are moved to their appropriate location, the foldedtubular sections125 of each leg can be unfolded to allow the distaltubular section130 and bifurcated proximaltubular section265 to extend in length. Anattachment anchor245 can be located at each outlet end148 although it is not required for the present invention to have anysuch attachment anchor245. Theattachment anchor245 located at each outlet end148 of the bifurcated intravascular foldedtubular member260 can be of a self-expandable or balloon-expandable nature as described earlier for theattachment anchor245 that can be located at theinlet end145. Theattachment anchor245 at eachoutlet end148 is then expanded or allowed to expand placing the distaltubular section130 into close contact with the wall of the native vessel or the native lumen wall. The bifurcated intravascular foldedtubular member260 has then been fully deployed to its radially deployedinlet end diameter105 and radially deployedoutlet end diameter110 and to its bifurcated deployed tubular member length290 (seeFIG. 4B). Each outlet end148 can be placed precisely in its desired position in the iliac or femoral artery while observing or real time fluoroscopy the placement of eachoutlet end148.
• The firm anchoring provided by theattachment anchor245 of this invention will ensure that theinlet end145 of the bifurcated intravascular foldedtubular member260 will not migrate during the unfolding of the foldedtubular section125 and after the bifurcated intravascular foldedtubular member260 is implanted. Theattachment anchor245 combined with the one-piece construction provides a leak free seal to completely isolate the aneurysmal space from theblood flow passage100 within the bifurcated intravascular foldedtubular member260. The wall structure allows a displaced attachment anchor760 (seeFIG. 20) to be attached to the bifurcated intravascular foldedtubular member260. The generally axialmetallic strands755 can extend proximally beyond theinlet end145 and form a direct attachment to the displaced attachment anchor760 (seeFIG. 20) by attaching to theintranodal openings385. It is understood that a straight intravascular foldedtubular member95 could have similarly been shown with the woven wall structure andattachment anchor245 described in this embodiment. The present invention is intended to include both straight95 and bifurcated260 intravascular folded tubular member including all of the features described in this disclosure.
Delivery Procedure
• It is further an additional embodiment of this invention to provide a bifurcated intravascular foldedtubular member260 that can be delivered and fully deployed either percutaneously or through a small surgical cutdown in onecommon femoral artery30 and placed within the aorta for treatment of abdominal aortic aneurysm without the need for access to the contralateral artery such as the contralateral commonfemoral artery30. This can be accomplished by first delivering the bifurcated intravascular foldedtubular member260 to the abdominal aorta at the site of the abdominalaortic aneurysm5 between the renal arteries and the aorto-iliac bifurcation57 (seeFIGS. 1A and 1B). After theinlet end145 of the bifurcated intravascular foldedtubular member260 has been placed proximal to the aortic injury, the entire bifurcated intravascular folded tubular member as shown inFIG. 4B,5, or23 can be located entirely within the abdominal aorta and proximal to aorto-iliac bifurcation57 (seeFIG. 1B). Oneoutlet end148 of the bifurcated intravascular foldedtubular member260 on the ipsilateral side can be deployed to its appropriate position in the iliac or femoral artery. Theoutlet end148 of the bifurcated intravascular foldedtubular member260 on the contralateral side can then be placed into appropriate position with a contralateral side outlet end placement means. This contralateral side outlet end placement means is introduced through the ipsilateral femoral artery and can move theoutlet end148 of the bifurcated intravascular foldedtubular member260 such that the foldedtubular section125 can unfold allowing the proximal or distal section to extend and provide an extension of the tubular member on the contralateral side so as to place theoutlet end148 in an appropriate position. Theattachment anchor245 located on the contralateral side is expanded or allowed to expand to hold theoutlet end148 of the bifurcated intravascular foldedtubular member260 securely in contact with the arterial wall or the inside of the vessel lumen.
• The present invention includes a one piece bifurcated intravascular foldedtubular member260 which is different than the modular systems described in the prior art for treating abdominal aortic aneurysm. The one piece construction of the present invention cannot form leak pathways such as those that occur between the union of various segments found in modular systems. The present intravascular tubular member provides a device for treating vascular injury such as abdominal aortic aneurysm where the axial length of the native lumen extending through the aortic aneurysm is very difficult to measure using angiographic means. Estimating the length angiographically will very often lead to an incorrect estimation of the length of intravascular graft that is needed. The result can be the implantation or another prior art stent-graft device that is too short and does not extend beyond the injured artery to the region that is not injured or healthy. If the prior art stent-graft is too long, it can extend beyond an appropriate point in the iliac or femoral artery and can block a side branch such as the internaliliac artery80. With theintravascular tubular member85 of the present invention, the length of theintravascular tubular member85 or vasculartubular member83 is determined in situ or while it is being placed. Therefore, theintravascular tubular member85 of the present invention can be extended precisely to the appropriate length without concern for the inaccuracies associated with trying to estimate the length of the tortuous path for the intravascular tubular member.

Claims (18)

1-34. (canceled)

35. A wall structure for a cylindrical member that is deliverable to the site of a lesion within a tubular vessel of the body, the cylindrical member having a nondeployed state and capable of undergoing an expansion deformation to a deployed state with a larger diameter, said wall structure comprised of;

A. one or more hinges and one or more struts,

B. said hinges being adapted to bend substantially only in the direction of the hinge width,

C. said struts having a strut width that is greater than a strut radial dimension wherein said strut is unable to bend substantially in the direction of the strut width and is adapted to flex elastically and not substantially plastically in the radial direction.

36. The wall structure ofclaim 35 wherein the said hinges provide a plastic deformation of a material as said hinges deform during the expansion deformation.

37. The wall structure ofclaim 36 wherein said struts formed of said material are adapted to bend elastically in the radial direction due to an external crush force and return to the original shape upon removal of the crush force, thereby providing a cylindrical member that is adapted to be balloon expandable but not plastically crushable.

38. The wall structure ofclaim 35 wherein said hinges have an expansion yield force in the direction of said hinge width and said struts have an outward crush elastic force in the radial direction that are uncoupled from each other thereby allowing these forces to be adjusted independently from each other.

39. The wall structure ofclaim 35 wherein said hinges provide an elastic expansion force in the direction of said hinge width that is uncoupled from a crush elastic force provided by said struts in a radial direction.

40. A cylindrical wall structure for use within a tubular vessel of the body, deliverable to a site that requires a supporting structure, said cylindrical wall structure having the ability to exert an expansion force outward that is transmitted toward the tubular vessel wall, said cylindrical wall structure further having an independent ability to tolerate a temporarily applied external crush force by becoming oval in shape and then returning back to its approximate initial shape upon removal of the external force, said tubular wall structure comprised of;

A. hinges and struts that are interconnected within said cylindrical wall structure,

B. said struts having a width enough greater than the width of said hinges such that the struts do not contribute significantly to the expansion force that is predominantly determined by said hinges,

C. said hinges having a radial dimension enough greater than the radial dimension of said struts such that the hinges do not contribute significantly to the elastic crush resistance force that is predominantly determined by said struts.

41. The method of use for a cylindrical member that is deliverable to the site of a lesion within a tubular vessel of the body, the cylindrical member having a nondeployed state and capable of undergoing an expansion deformation to a deployed state of larger diameter, the method comprising; providing a wall structure with hinges and struts, said hinges being adapted to be unable to bend substantially in the radial direction; said struts being adapted to be substantially unbendable in the direction of the strut width and adapted to flex elastically and not significantly plastically in the radial direction; whereby said cylindrical member is thereby adapted to reversibly form an oval shape during a crush deformation.

42. The method of use ofclaim 41 wherein at least some of said hinges bend plastically in the direction of the hinge width during the expansion deformation thereby adapting said cylindrical member to be balloon expandable while said struts adapt said cylindrical member to not be plastically crushable.

43. The method ofclaim 41 wherein the hinge width is made wider to increase the force required to pivot the hinge.

44. The method ofclaim 41 wherein said hinge has a hinge length that is decreased to cause a relatively elastic material to bend plastically within a relatively small amount of rotation.

45. The method ofclaim 41 wherein said hinge has a hinge length that is increased to cause a relatively plastic material to bend elastically throughout a relatively large amount of rotation.

46. The method ofclaim 41 wherein the hinge radial dimension is increased beyond that which is necessary to prevent the strut from causing said hinge to flex in the radial direction, thereby providing an increase the force required to pivot the hinge.

47. The method ofclaim 41 wherein the strut radial dimension is made thicker to increase the force required to flex said strut in the radial direction.

48. The method ofclaim 41 wherein the strut radial dimension is decreased to reduce the force required to flex said strut in the radial direction, and adapt said strut when formed from a relatively plastic material to bend elastically throughout a relatively large degree of flexing in the radial direction.

49. The method ofclaim 41 wherein said strut width is made wider than that which is necessary to prevent bending in the direction which said hinges pivot, thereby providing an increase in the force required to flex said strut in the radial direction.

50. The method ofclaim 41 wherein said strut has a strut length that is increased to cause said strut when formed from a relatively plastic material to bend elastically throughout a relatively large degree of flexing in the radial direction.

51. The method ofclaim 41 wherein the hinge width and hinge radial dimension of any of said hinges, and the strut width and strut radial dimension of any of said struts are adapted to have different hinge width and hinge radial dimension than another of said hinges and different strut width and strut radial dimension than another of said struts.

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