US20030004560A1 - Delivery system and method for bifurcated graft - Google Patents

Abstract

A flexible low profile delivery system for delivery of an expandable intracorporeal device, specifically, an endovascular graft, which has at least one belt circumferentially disposed about the device in a constraining configuration. The belt is released by a release member, such as a release wire, by retracting the wire from looped ends of the belt. Multiple belts can be used and can be released sequentially so as to control the order of release and placement of the endovascular graft. An outer protective sheath may be disposed about the endovascular graft while in a constrained state which must first be retracted or otherwise removed prior to release of the graft from a constrained state. The delivery system can be configured for delivery over a guiding device such as a guidewire. The delivery system can also be configured for delivery of bifurcated intracorporeal devices.

Description

RELATED APPLICATIONS
• This application is a continuation-in-part of U.S. patent application Ser. No. 09/917,371, filed Jul. 27, 2001, by Michael V. Chobotov et aL., entitled “Delivery System and Method for Bifurcated Endovascular Graft”, which is a continuation-in-part of U.S. patent application, Ser. No. 09/834,278, filed Apr. 11, 2001, by Michael V. Chobotov et aL, entitled “Delivery System and Method for Endovascular Graft,” Each application is hereby incorporated by reference herein in its entirety.[0001]
BACKGROUND
• The present invention relates generally to a system and method for the treatment of disorders of the vasculature. More specifically, a system and method for treatment of thoracic or abdominal aortic aneurysm and the like, which is a condition manifested by expansion and weakening of the aorta. Prior methods of treating aneurysms have consisted of invasive surgical methods with graft placement within the affected vessel as a reinforcing member of the artery. However, such a procedure requires a surgical cut down to access the vessel, which in turn can result in a catastrophic rupture of the aneurysm due to the decreased external pressure from the surrounding organs and tissues, which are moved during the procedure to gain access to the vessel. Accordingly, surgical procedures can have a high mortality rate due to the possibility of the rupture discussed above in addition to other factors. Other risk factors for surgical treatment of aortic aneurysms can include poor physical condition of the patient due to blood loss, anuria, and low blood pressure associated with the aortic abdominal aneurysm. An example of a surgical procedure is described in a book entitled[0002]Surgical Treatment of Aortic Aneurysmsby Cooley published in 1986 by W.B. Saunders Company.
• Due to the inherent risks and complexities of surgical intervention, various attempts have been made to develop alternative methods for deployment of grafts within aortic aneurysms. One such method is the non-invasive technique of percutaneous delivery by a catheter-based system. Such a method is described in Lawrence, Jr. et al. in “Percutaneous endovascular graft: experimental evaluation”,[0003]Radiology(May 1987). Lawrence described therein the use of a Gianturco stent as disclosed in U.S. Pat. No. 4,580,568. The stent is used to position a Dacron fabric graft within the vessel. The Dacron graft is compressed within the catheter and then deployed within the vessel to be treated. A similar procedure has also been described by Mirich et al. in “Percutaneously placed endovascular grafts for aortic aneurysms: feasibility study,”Radiology(March 1989). Mirich describes therein a self-expanding metallic structure covered by a nylon fabric, with said structure being anchored by barbs at the proximal and distal ends.
• One of the primary deficiencies of the existing percutaneous devices and methods has been that the grafts and the delivery systems used to deliver the grafts are relatively large in profile, often up to 24 French, and stiff in longitudinal bending. The large profile and relatively high bending stiffness of existing delivery systems makes delivery through the vessels of a patient difficult and can pose the risk of dissection or other trauma to the patient's vessels. In particular, the iliac arteries of a patient are often too narrow or irregular for the passage of existing percutaneous devices. Because of this, non-invasive percutaneous graft delivery for treatment of aortic aneurysm is contraindicated for many patients who would otherwise benefit from it.[0004]
• What is needed is an endovascular graft and delivery system having a small outer diameter relative to existing systems and high flexibility to facilitate percutaneous delivery in patients who require such treatment. What is also needed is a delivery system for an endovascular graft that is simple, reliable and that can accurately and safely deploy an endovascular graft within a patient's body, lumen or vessel.[0005]
SUMMARY
• The invention is directed generally to a delivery system for delivery of an expandable intracorporeal device, specifically, an endovascular graft. Embodiments of the invention are directed to percutaneous non[0006]5 invasive delivery of endovascular grafts which eliminate the need for a surgical cut-down in order to access the afflicted artery or other intracorporeal conduit of the patient being treated. Such a non-invasive delivery system and method result in shorter procedure duration, expedited recovery times and lower risk of complication. The flexible low profile properties of some embodiments of the invention also make percutaneous non-invasive procedures for delivery of endovascular grafts available to patient populations that may not otherwise have such treatment available. For example, patients with small anatomies or particularly tortuous vasculature may be contraindicated for procedures that involve the use of delivery systems that do not have the flexible or low profile characteristics of embodiments of the present invention.
• In one embodiment, the delivery system has an elongate shaft with a proximal section and a distal section. The distal section of the elongate shaft includes a portion having an expandable intracorporeal device. An elongate belt support member is disposed adjacent a portion of the expandable intracorporeal device and a belt is secured to the belt support member and circumferentially disposed about the expandable intracorporeal device. The belt member constrains at least a portion of the expandable intracorporeal device. A release member releasably secures the belt in the constraining configuration.[0007]
• Another embodiment of the invention is directed to a delivery system that has an elongate shaft with a proximal section and a distal section. The distal section of the elongate shaft has an elongate belt support member disposed adjacent a portion of the expandable intracorporeal device. A belt is secured to the belt support member and is circumferentially disposed about the expandable intracorporeal device. The belt has a configuration which constrains the expandable intracorporeal device and a release member releasably secures the belt in the constraining configuration. The belt may constrain any portion of the expandable intracorporeal device, such as a self-expanding portion of the expandable intracorporeal device. A self-expanding portion of the device may include a self-expanding member such as a tubular stent.[0008]
• In a particular embodiment of the invention, a plurality of belts are secured to various axial positions on the belt support member, are circumferentially disposed about the expandable intracorporeal device and have a configuration which constrains the expandable intracorporeal device. At least one release member releasably secures the belts in the constraining configuration. Each belt can be released by a single separate release member which engages each belt separately, or multiple belts can be released by a single release member. The order in which the belts are released can be determined by the axial position of the belts and the direction of movement of the release member.[0009]
• Another embodiment of the invention is directed to a delivery system for delivery of a self-expanding endovascular graft with a flexible tubular body portion and at least one self-expanding member secured to an end of the endovascular graft. The delivery system has an elongate shaft having a proximal section and a distal section. The distal section of the elongate shaft has an elongate belt support member disposed within the self-expanding member of the endovascular graft and a belt that is secured to the belt support member adjacent the self-expanding member. The belt is also circumferentially disposed about the self-expanding member and has a configuration that constrains the self-expanding member. A release wire releasably secures ends of the belt in the constraining configuration.[0010]
• A further embodiment of the invention includes a delivery system for delivery of an endovascular graft with a flexible tubular body portion and a plurality of self-expanding members secured to ends of the endovascular graft. The delivery system has an elongate shaft with a proximal section and a distal section. The distal section of the elongate shaft has an elongate guidewire tube disposed within the endovascular graft in a constrained state. A plurality of shape memory thin wire belts are secured to the guidewire tube respectively adjacent the self-expanding members. The belts are circumferentially disposed about the respective self-expanding members and have a configuration that constrains the respective self-expanding members. A first release wire releasably secures ends of the belts disposed about the self-expanding members at the proximal end of the endovascular graft in a constraining configuration. A second release wire releasably secures ends of the belts disposed about the self-expanding members at a distal end of the endovascular graft in the constraining configuration.[0011]
• The invention also is directed to a method for deploying an expandable intracorporeal device within a patient's body. The method includes providing a delivery system for delivery of an expandable intracorporeal device including an elongate shaft having a proximal section and a distal section. The distal section of the elongate shaft has an elongate belt support member disposed adjacent a portion of the expandable intracorporeal device and a belt which is secured to the belt support member. The belt is circumferentially disposed about the expandable intracorporeal device and has a configuration that constrains the expandable intracorporeal device. A release member releasably secures the belt in the constraining configuration.[0012]
• Next, the distal end of the delivery system is introduced into the patient's body and advanced to a desired site within the patient's body. The release member is then activated, releasing the belt from the constraining configuration. Optionally, the delivery system may also have an outer protective sheath disposed about the endovascular graft in a constrained state, the belt in its constraining configuration and at least a portion of the release wire disposed at the belt. In such an embodiment, the method of deployment of an expandable intracorporeal device also includes retraction of the outer protective sheath from the endovascular graft prior to activation of the release member.[0013]
• In an embodiment of the invention directed to delivery of bifurcated intracorporeal device, an elongate shaft has a proximal section and a distal section. The distal section of the shaft has an elongate primary belt support member and at least one primary belt disposed on the primary belt support member. The primary belt support member is configured to be circumferentially disposed about a bifurcated intracorporeal device and at least partially constrain the device. A primary release member is configured to engage and releasably secure the primary belt in a constraining configuration. At least one elongate secondary belt support member is disposed adjacent the elongate primary belt support member. At least one secondary belt is disposed on the secondary belt support member. This at least one secondary belt is configured to be circumferentially disposed about a bifurcated intracorporeal device and at least partially constrain the device. A secondary release member is configured to engage and releasably secure the secondary belt in a constraining configuration.[0014]
• In a method for deploying a bifurcated intracorporeal device within a patient's body, a delivery system for delivery and deployment of a bifurcated intracorporeal device is provided. The delivery system includes an elongate shaft having a proximal section and a distal section. The bifurcated intracorporeal device is disposed on the distal section of the elongate shaft. The distal section of the elongate shaft also includes an elongate primary belt support member and at least one primary belt secured to the primary belt support member. The primary belt is configured to be circumferentially disposed about a bifurcated intracorporeal device and at least partially constrain the device. A primary release member engages and releasably secures the primary belt in the constraining configuration. The distal section of the elongate shaft also includes at least one elongate secondary belt support member disposed adjacent the elongate primary belt support member. At least one secondary belt is secured to the secondary belt support member and is configured to be circumferentially disposed about a bifurcated intracorporeal device to at least partially constrain the device. A secondary release member engages and releasably secures the secondary belt in a constraining configuration.[0015]
• The distal end of the delivery system is introduced into the patient's body and advanced to a desired site within the patient's body. The release members are then activated to release the belts from the constraining configuration and the device is deployed. Thereafter, the delivery system can be removed from the patient's body. In some embodiments of the invention, the secondary belt support member is detached and removed from the delivery system prior to withdrawal of the delivery system from the patient. In another embodiment, the secondary belt support member is displaced laterally towards the primary belt support member so as to be substantially parallel to the primary belt support member and enable withdrawal of the delivery system through an ipsilateral side of the bifurcated intracorporeal device.[0016]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is an elevational view in partial longitudinal section illustrating an embodiment of a delivery system for an expandable intracorporeal device having features of the invention.[0017]
• FIG. 2 is a transverse cross sectional view of the delivery system of FIG. 1 taken along lines[0018]2-2 of FIG. 1.
• FIG. 3 is a transverse cross sectional view of the delivery system of FIG. 1 taken along lines[0019]3-3 of FIG. 1.
• FIG. 4 is a transverse cross sectional view of the delivery system of FIG. 1 taken along lines[0020]4-4 of FIG. 1.
• FIG. 5 is a transverse cross sectional view of the delivery system of FIG. 1 taken along lines[0021]5-5 of FIG. 1.
• FIG. 6A is an enlarged elevational view in partial section of the delivery system in FIG. 1.[0022]
• FIG. 6B is an enlarged elevational view in partial section of the delivery system of FIG. 1 with portions of the graft and self-expanding members cut away for clarity of view of the belt bushings.[0023]
• FIG. 7A is a perspective view showing release belt configurations having features of the invention.[0024]
• FIG. 7B is a perspective view showing an alternative embodiment of release belts.[0025]
• FIG. 7C is an end view showing an alternative embodiment of release belts.[0026]
• FIG. 7D is a perspective view of the embodiment of FIG. 7C.[0027]
• FIG. 7E is an enlarged view of a particular coupling configuration between end loops of release belts.[0028]
• FIG. 7F is a perspective view, partially cut away, of a particular embodiment of an end loop of a release belt.[0029]
• FIG. 7G is a perspective view of an alternative embodiment of a release belt.[0030]
• FIG. 7H is a perspective view of an alternative embodiment of a release belt.[0031]
• FIG. 7I is a perspective view of an alternative embodiment of a branched release wire.[0032]
• FIG. 7J is an end view showing an alternative embodiment of a release belt.[0033]
• FIG. 7K is a transverse cross sectional view showing the alternative embodiment of the release belt configuration of FIG. 7J constraining a self-expanding member.[0034]
• FIG. 7L is a detail of the connection formed where a release wire is used with the alternative release belt embodiment of FIGS.[0035]7J-7K.
• FIG. 8 is an elevational view in partial section of the proximal adapter shown in FIG. 1.[0036]
• FIG. 9 is a diagrammatic view of a patient's body illustrating the patient's heart, aorta, iliac arteries, femoral arteries, and a delivery system having features of the invention disposed within the femoral artery and aorta.[0037]
• FIG. 10 is a diagrammatic view of a delivery system having features of the invention disposed within an artery of a patient with an expandable intracorporeal device being deployed within the artery.[0038]
• FIG. 11 is a diagrammatic view of a delivery system having features of the invention disposed within an artery of a patient with an expandable intracorporeal device being deployed within the artery.[0039]
• FIG. 12 is an enlarged diagrammatic view of a delivery system having features of the invention disposed within an artery of a patient with an expandable intracorporeal device being deployed within the artery.[0040]
• FIG. 13 is an elevational view in partial section of a connection between an inflation tube and an inflation port of an endovascular graft.[0041]
• FIG. 14 is an elevational view in partial longitudinal section illustrating an embodiment of a delivery system for an expandable intracorporeal device having features of the invention.[0042]
• FIG. 15 is a transverse cross sectional view of the delivery system of FIG. 14 taken along lines[0043]15-15 in FIG. 14.
• FIG. 16 is an enlarged elevational view in partial section of the delivery system shown in FIG. 14.[0044]
• FIG. 17 is an elevational view in partial section of the proximal adapter of the delivery system shown in FIG. 14.[0045]
• FIG. 18 is an elevational view in partial section of an alternative embodiment of the proximal adapter of the delivery system shown in FIG. 14 with a nested handle configuration.[0046]
• FIG. 19 is an elevational view of a bifurcated stent graft suitable for delivery and deployment by embodiments of the invention.[0047]
• FIG. 20 is a transverse cross sectional view of the stent graft of FIG. 19 taken along lines[0048]20-20 in FIG. 19.
• FIG. 21 is a transverse cross sectional view of the stent graft of FIG. 19 taken along lines[0049]21-21 of FIG. 19.
• FIG. 22 is a transverse cross sectional view of the stent graft of FIG. 19 taken along lines[0050]22-22 of FIG. 19.
• FIG. 23 is an elevational view in partial section of an embodiment of a delivery system having features of the invention.[0051]
• FIG. 24 is a transverse cross sectional view of the delivery system of FIG. 23 taken along lines[0052]24-24 of FIG. 23.
• FIG. 25 is a transverse cross sectional view of the delivery system of FIG. 23 taken along lines[0053]25-25 of FIG. 23.
• FIG. 26 is an elevational view in partial section showing an enlarged view of a distal portion of the delivery system of FIG. 23.[0054]
• FIG. 27 is a transverse cross sectional view of the delivery system of FIG. 26 taken along lines[0055]27-27 of FIG. 26.
• FIG. 28 is a transverse cross sectional view of the delivery system of FIG. 26 taken along lines[0056]28-28 of FIG. 26.
• FIG. 28A is a transverse cross sectional view of an alternative embodiment of a secondary belt support member of a delivery system similar in function to that shown in FIG. 28.[0057]
• FIG. 28B is an elevational view of the alternative embodiment of the secondary belt support member of FIG. 28A.[0058]
• FIG. 29 is a transverse cross sectional view of the delivery system of FIG. 26 taken along lines[0059]29-29 of FIG. 26.
• FIG. 30 is a transverse cross sectional view of the delivery system of FIG. 26 taken along lines[0060]30-30 in FIG. 26.
• FIG. 31 is an elevational view in partial section of the proximal adapter of the delivery system of FIG. 23.[0061]
• FIG. 31A is an elevational view in partial section of the proximal adapter of the delivery system of FIG. 23, showing an optional ripcord and flexible fill cathether.[0062]
• FIG. 31B is a simpler cross sectional schematic view of a bent or angled contralateral leg inflatable channel having a bead or lumen patency member disposed in a channel lumen taken along[0063]line31B-31B in FIG. 19.
• FIG. 32 is a perspective view of the belt support member assembly at a distal portion of the delivery system of FIG. 23.[0064]
• FIG. 33 illustrates a portion of the internal vasculature of a patient, including the aorta, iliac and femoral arteries branching therefrom.[0065]
• FIG. 34 is a magnified view of the abdominal aorta area of the patient shown in FIG. 33 and shows a guidewire positioned in the aorta from the right iliac artery.[0066]
• FIGS.[0067]35-37 illustrate the magnified view of the abdominal aorta of the patient shown in FIG. 33 and depict a deployment sequence of the bifurcated endovascular stent graft of FIG. 19 with the delivery system of FIG. 23.
• FIG. 37A is a perspective view of a marker disposed on the delivery system distal section in the vicinity of the nosepiece.[0068]
• FIG. 37B is a perspective view of an alternative embodiment of a marker for use in the delivery system of the present invention.[0069]
• FIGS.[0070]38-52 continue to illustrate a deployment sequence of the bifurcated endovascular stent graft of FIG. 19.
• FIGS.[0071]53-57 illustrate a number of alternative catheter distal shaft arrangements in which a well is provided to facilitate the orderly and tangle-free withdrawal of the release strand from the delivery catheter.
• FIGS.[0072]58-60 illustrate a further alternative belt support member and contralateral leg delivery system configurations and operation.
DETAILED DESCRIPTION
• FIGS.[0073]1-8 and10 illustrate an embodiment ofdelivery system10 for delivering a variety of expandable intracorporeal devices; specifically, an expandableendovascular graft11. One such expandableendovascular graft11 useful for delivery and deployment at a desired site within a patient is disclosed in co-pending U.S. patent application Ser. No. 09/133,978, filed Aug. 14, 1998, by M. Chobotov, which is hereby incorporated by reference in its entirety.
• [0074]Delivery system10 in FIG. 1 has anelongate shaft12 with aproximal section13, adistal section14, aproximal end15 and adistal end16. Thedistal section14 has an elongate belt support member in the form of aguidewire tube17 disposed adjacent a portion of the expandableendovascular graft11. Aguidewire18 is disposed withinguidewire tube17. A plurality ofbelts21,22, and23 are secured to theguidewire tube17 and are circumferentially disposed about portions of theendovascular graft11. FIG. 1 shows the belts in a configuration that constrains theendovascular graft11. First andsecond release members24 and25 releasablysecure belts21,22, and23 in a constraining configuration as shown.
• The[0075]endovascular graft11 has aproximal end26, adistal end27, a proximalinflatable cuff28, a distalinflatable cuff30, a proximal self-expandingmember31, a first distal self-expandingmember32 and a second distal self-expandingmember33. As defined herein, the proximal end of the elongate shaft is theend15 proximal to an operator of thedelivery system10 during use. The distal end of the elongate shaft is theend16 that enters and extends into the patient's body. The proximal and distal directions for thedelivery system10 andendovascular graft11 loaded within thedelivery system10 as used herein are the same. This convention is used throughout the specification for the purposes of clarity, although other conventions are commonly used. For example, another useful convention defines the proximal end of an endovascular graft as that end of the graft that is proximal to the source of blood flow going into the graft. Such a convention is used in the previously discussed co-pending patent application, Ser. No. 09/133,978, although that convention is not adopted herein.
• The[0076]guidewire tube17 has aninner lumen34, as shown in FIG. 2, adistal section35, aproximal end36, as shown in FIG. 8, and adistal end37. Theinner lumen34 of theguidewire tube17 terminates at thedistal end37 with a distalguidewire tube port38, as shown in FIG. 10. As seen in FIG. 8, theproximal end36 ofguidewire tube17 terminates in aport41 disposed in theproximal adapter42. Theport41 is typically a tapered fitting such as a Luer lock fitting which facilitates the attachment of a hemostasis valve (not shown). Theguidewire tube17 is a hollow tubular member that normally has an annular cross section, although oval cross-sectional profiles and others are also suitable.
• A portion of the[0077]distal section35 of theguidewire tube17, shown in FIG. 1, is disposed within aninner lumen43 of adistal nose piece44, as shown in FIG. 5.Distal nose piece44 is configured in a streamlined bullet shape for easy passage within a patient lumen or vessel such asaorta45.Guidewire tube17 may be bonded to theinner lumen43 of thenose piece44, or it may be molded into thenose piece44 during manufacture. Referring to FIG. 1, thenose piece44 has adistal portion46, anintermediate portion47 and aproximal shoulder portion48 configured to slidingly engage thedistal portion51 of aninner lumen52 of anouter tubular member53.
• Referring to FIGS. 1, 6A,[0078]6B and7A, on thedistal section35 ofguidewire tube17, proximal to theproximal shoulder portion48 ofnose piece44, a firstdistal belt21 is secured to theguidewire tube17. The first distal belt may be secured to theguidewire tube17 with any suitable adhesive such as cyanoacrylate, epoxy or the like. Both free ends55 and56 of the firstdistal belt21 are secured to theguidewire tube17. Theguidewire tube17 may be made from a variety of suitable materials including polyethylene, teflon, polyimide and the like.
• Referring to FIGS.[0079]2-5, theinner lumen34 of theguidewire tube17 has an inside diameter that can accommodate a guidewire suitable for guiding a device such asdelivery system10. Theinner lumen34 of theguidewire tube17 may have an inside diameter of about 0.015 inch to about 0.045 inch; specifically, about 0.020 inch to about 0.040 inch. The outer diameter of theguidewire tube17 may range from about 0.020 inch to about 0.060 inch; specifically, about 0.025 inch to about 0.045 inch.
• Referring again to FIGS. 6A, 6B and[0080]7A, an optional firstdistal belt bushing57 is disposed about theguidewire tube17 so as to cover the portions of the free ends55 and56 of the firstdistal belt21 that are secured to thedistal section35 of theguidewire tube17. Thisbushing57 may also serve to control the constrained configuration of the belted self-expanding members, and may include geometric features to engage or support the belted members. A similar configuration is present at a seconddistal belt22 which has free ends secured to theguidewire tube17 proximal to the firstdistal belt21. A seconddistal belt bushing63 is disposed about theguidewire tube17 so as to cover the portions of the free ends of the seconddistal belt22 that are secured to theguidewire tube17. Aproximal belt23 has free ends secured to theguidewire tube17 proximal to the seconddistal belt22 and has an optionalproximal belt bushing67, as shown in FIG. 6, configured similarly to the first and seconddistal belt bushings57 and63.
• The[0081]belts21,22 and23 can be made from any high strength, resilient material that can accommodate the tensile requirements of the belt members and remain flexible after being set in a constraining configuration. Typically,belts21,22 and23 are made from solid ribbon or wire of a shape memory alloy such as nickel titanium or the like, although other metallic or polymeric materials are possible.Belts21,22 and23 may also be made of braided metal filaments or braided or solid filaments of high strength synthetic fibers such as Dacron®, Spectra or the like. An outside transverse cross section of thebelts21,22 and23 may range from about 0.002 to about 0.012 inch, specifically, about 0.004 to about 0.007 inch. The cross sections ofbelts21,22 and23 may generally take on any shape, including rectangular (in the case of a ribbon), circular, elliptical, square, etc.
• In general, we have found that a ratio of a cross sectional area of the belts to a cross sectional area of the release members,[0082]24 and25, of about 1:2 is useful to balance the relative strength and stiffness requirements. Other ratios, however, may also be used depending on the desired performance characteristics.
• The inner diameters of[0083]belt bushings57,63 and67 are sized to have a close fit over theguidewire tube17 and securedportion71, as shown in FIG. 7A, of the free ends of thebelts21,22 and23 that are secured to theguidewire tube17. Typically, the inner diameter of thebelt bushings57,63 and67 range from about 0.025 inch to about 0.065 inch; specifically, about 0.030 inch to about 0.050 inch. In addition, the outer diameter ofbelt bushing57 may be sized to approximate aninner diameter70, as shown in FIG. 4, of the respective first distal self-expandingmember32 of theendovascular graft11 when themember32 is in a fully constrained state. Theother belt bushings63 and67 may be similarly configured with respect to the second distal self-expandingmember33 and the proximal self-expandingmember31.
• Such an arrangement keeps the self-expanding[0084]members31,32 and33 properly situated when in a constrained state and prevents the various portions of the self-expandingmembers31,32 and33 from overlapping or otherwise entangling portions thereof while in a constrained state. The outer diameter of thebelt bushings57,63 and67 may range from about 0.040 inch to about 0.200 inch; specifically, about 0.060 inch to about 0.090 inch. The material of thebelt bushings57,63 and67 may be any suitable polymer, metal, alloy or the like that is bondable. Generally, thebelt bushings57,63 and67 are made from a polymer such as polyurethane, silicone rubber or PVC plastic.
• As shown in FIG. 7A,[0085]belts21,22 and23 extend radially from theguidewire tube17 throughoptional standoff tubes72,73 and74.Standoff tubes72,73 and74 are disposed about belts21-23 adjacent theguidewire tube17 and act to prevent separation of belts21-23 in a circumferential direction as tension is applied to the belts. Standoff tubes72-74 also prevent belts21-23 from applying other undesirable forces on portions of theendovascular graft11 that are constrained by the belts. Specifically, the standoff tubes72-74 prevent the belts21-23 from spreading the self-expanding members31-33, or portions thereof, at those locations where the belts21-23 extend radially through the self-expanding members.
• The standoff tubes[0086]72-74 typically have a length substantially equal to a single wall thickness of the self-expandingmembers31,32 and33. The length of the standoff tubes72-74 may range from about 0.010 inch to about 0.030 inch. An inner diameter of aninner lumen75 of the standoff tubes, as shown in FIG. 4, may range from about 0.004 to about 0.024 inch, with a wall thickness of the standoff tubes being about 0.002 inch to about 0.006 inch. Typically, the standoff tubes72-74 are made from a high strength metal or alloy such as stainless steel, although they may be polymeric as well.
• Belts[0087]21-23 exit the outer apertures of standoff tubes72-74 and extend circumferentially about the respective portions of the expandableintracorporeal device11. The term “circumferential extension” as used with regard to extension of the belts21-23 is meant to encompass any extension of a belt in a circumferential direction. The belts may extend circumferentially a full 360 degrees, or any portion thereof. For example, belts or belt segments may extend partially about an endovascular device, and may be combined with other belts or belt segments that also partially extend circumferentially about an endovascular device. Typically, a plane formed by each of the belts21-23 when in a constraining configuration is generally perpendicular to a longitudinal axis76, shown in FIG. 1, of thedistal section14 ofshaft12. As shown in FIGS. 6A and 6B, loop ends81,82 and83 of thebelts21,22 and23, respectively, are releasably locked together by one or more release members. For example, in the embodiment shown in FIG. 1, a release member in the form of afirst release wire24 is shown disposed withinend loops81 of the firstdistal belt21 andend loops82 of the seconddistal belt22 so as to secure the first and seconddistal belts21 and22 in a constraining configuration about theendovascular graft11. Another release member in the form of asecond release wire25 is shown disposed withinend loops83 of theproximal belt23 so as to secure theproximal belt23 in a constraining configuration about theendovascular graft11.
• A single release wire may also be used to perform the function of each of the first and second release wires,[0088]24 and25, so that firstdistal belt21, seconddistal belt22, andproximal belt23 may be releasably secured by a single release wire. A highly controlled, sequential belt deployment scheme may be realized with the use of a single release wire.
• Any number of release wires and belts as may be needed to effectively secure and deploy[0089]graft11, in combination, are within the scope of the present invention.
• In some embodiments of the invention, when constrained, the end loops of any single belt touch each other or are spaced closely together such that the belt as a whole forms a substantially circular constraint lying substantially in a plane.[0090]Release wire24 and25 may be made from suitable high strength materials such as a metal or alloy (e.g., stainless steel) which can accommodate the torque force applied to the release wire by thebelt end loops83 when thebelts23 are under tension from the outward radial force of the constrained portions of theendovascular graft11, i.e., the self-expandingmembers32 and33.
• The[0091]release wires24 and25 may generally have an outer diameter ranging from about 0.006 to about 0.014 inch.Distal end portions84 and85 ofrelease wires24 and25, respectively, may terminate at any appropriate site distal of the end loops81-83 of belts21-23. As shown in FIG. 8, the proximal ends86 and87 of therelease wires24 and25 extend through theelongate shaft12 of thedelivery system10 throughproximal ports91 and92 on theproximal adapter42, respectively, and terminate at respective release wire handles93 and94 which are releasably secured to theproximal adapter42.
• FIG. 7B illustrates an alternative embodiment of the belts[0092]21-23 of FIG. 7A. In FIG. 7A, belts21-23 are shown as each consisting of a single strand of wire formed into the end loops81-83, respectively, with the end loops in an overlapping configuration. Free ends55 and56 ofbelt81 are shown secured to thedistal section35 of theguidewire tube17. In contrast, FIG. 7B, wherein like elements with regard to FIG. 7A are shown with like reference numerals, showsbelts21B,22B and23B formed of two strands of wire, with each strand formed into a single loop which overlaps a loop of the other strand to formend loops81B,82B and83B. The free ends of thebelts21B-23B may be secured in a similar manner to those of free ends55 and56 of FIG. 7A.
• Turning now to FIGS. 7C and 7D, alternative embodiments for portions of the delivery system of the present invention are shown. FIGS. 7C and 7D illustrate[0093]alternative belts21C,22C and23C disposed onguidewire tube17. Single ormultiple belts21C-23C may be deployed at various locations alongguidewire tube17 as desired. In addition, themembers comprising belts21C-23C are shown as a single line. However,belts21C-23C may be of a single- or multiple strand or filament design with various cross-sectional shapes as previously described. A single solid ribbon or wire is particularly useful.
• [0094]Belts21C-23C shown in FIGS. 7C and 7D are a single strand filament wrapped aroundguidewire tube17 and fixed thereon via any number of suitable techniques, such as gluing with adhesive, mechanical fixation, etc. Especially useful is fixing the belt with an ultraviolet-curable adhesive.
• Alternatively,[0095]belts21C-23C may comprise two strand filaments each wrapped aroundguidewire tube17 so that, for instance,belt21C is a two-filament component.
• [0096]Belt21C includesbelt arms112 and114, each of which, in the embodiments shown, is a loop of filament twisted upon itself to form a helix. Any number of twists may be imparted toarms112 and114 to provide a relatively loose or relatively tight helix as desired. Typically the number of twists (with a single twist being defined as a single overlap of wire segment) in eachbelt arm112 and114 numbers from zero to about 50 or more; specifically, about two to about 10. The choice of material used forbelt21C is an important factor in determining the optimum number of twists for each belt arm. Beltarms112 and114 may be formed into other configurations (e.g., braid, double helix, etc.) as well.
• Disposed within the end loops of the[0097]belt arms112 and114 are distal apertures oropenings120,122, respectively. During assembly of the delivery system, a release wire (such as wire24) is passed through eachaperture120,122 after the belt arms are wrapped around the graft self-expanding member, preferably in a circumferential groove as further described below. The release wire may also be disposed through any aperture created along the length ofbelt arms112,114 by each helix twist, although thedistal-most apertures120,122 are preferred.
• The wire optionally may be welded, glued, or otherwise fixed to itself at discrete points or along all or any portion of[0098]belt arms112,114, save theircorresponding apertures120 and122. For instance, the belt arm wire may be glued or welded to itself at the overlap or twist points, such as points124.
• FIG. 7D shows an optional[0099]belt arm sleeve126 that may be used to enclose a portion of one or bothbelt arms112,114, or any of the other belt embodiments contemplated herein.Belt112 is shown in FIG. 7D being constrained or covered over a length thereof by a flexible sleeve or coating126 (or alternatively, a coil wrapping or by fixing the loop to itself by adhesives, welding, soldering, brazing, etc.). Sleeve orcoating126 may optionally be shrink-wrapped, crimped, or otherwise configured to constrain or coverbelt arm112 therein. These fixation and sleeve features help to minimize the potential of belt arm untwisting and tend to close or block some or all of the helix apertures along the length except those through which the release wire are intended to pass. They can also provide greater structural and operational stability to the catheter system as a whole.
• [0100]Belt arm sleeve126 can be configured to have a transverse dimension that is sized to fit a twisted belt arm with fixed nodal points such as thebelt arm112 shown in FIG. 7D. In order to accommodate such atwisted belt arm112, the inner diameter and outer diameter would be large relative to a transverse dimension of the wire material that forms thebelt arm112. However, thebelt arm sleeve126 can also be only slightly larger in transverse dimension that the wire that forms the belt arm. For example, embodiments of belt arms that do not have twisted wires may have asleeve126 that fits closely or tightly over two strands of wire forming a belt arm. Thesleeve126 can cover substantially the entire length of such an untwisted belt arm from at least the guidewire tube to just proximal of the distal loop, such asdistal loop120. The distal loop should remain exposed for engagement by a release wire. In such an embodiment, the sleeve covered portion of the belt arm may also be wrapped around and secured to the guidewire tube just as the unsleeved belt portion of thebelt arm112 shown in FIG. 7D is shown at71C. This type of low profile belt arm sleeve may also be used to cover twisted belt arm embodiments, although a slightly larger diameter sleeve would be required.
• It may be desirable to impart a particular free resting angle to the[0101]belt arms112,114 to improve the reliability of the system and further reduce the possibility of thearms112 and114 interfering with other components of the prosthesis or delivery system. The FIG. 7C view showsbelt arms112,114 symmetrically disposed at an angle α as measured from ahorizontal plane125. This angle α may range from zero to 180 degrees. For example, one or bothbelt arm112,114 may lie alongplane125 or they may rest in the configuration shown (α=45 degrees). Any known techniques may be used to impart a desired resting configuration to the system, such as, for example, cold working or shape-setting by way of an athermal phase transformation (in the case of shape memory alloys).
• FIG. 7J shows a single belt example of the version shown in FIGS. 7C and 7D. Here, a[0102]single belt arm113 is shown disposed about thedistal end35 ofguidewire tube17.Belt arm113 is significantly longer than eitherbelt arm112 or114 of the FIGS.7C-7D embodiment so that it may extend at least around the circumference of any one ofself10 expanding members31,32, or33. Thedistal portion115 ofbelt arm113 meets a moreproximal portion117 where one or both strands (when thebelt arm113 is a twisted variety) extends through anend loop119 in thebelt arm115 distal portion. As discussed with other embodiments, a release member such asrelease wire24 may be inserted throughend loop119 and the intersecting portion of the belt armproximal portion117 to releasablysecure belt arm113 in a constraining configuration about theendovascular graft11. FIG. 7K depicts a simplified schematic cross-sectional view of belt arm113 (shown here untwisted) held in place by arelease wire24 about an exemplary self-expandingmember32. FIG. 7L is a detail of the connection formed whererelease wire24 intersects the distal and proximal portions,115 and117, respectively, ofbelt arm113.
• All of the features discussed herein with respect to the FIGS.[0103]7C-7D embodiment may be employed in the embodiment of FIGS.7J-7K as well.
• This helix configuration shown in the embodiments of FIGS.[0104]7C-7D and7J-7L is a particularly reliable configuration. It reduces the possibility that a portion ofbelt21C becomes entangled with a self-expanding member (such asmembers31,32 and33) or otherwise interferes with the safe and effective deployment of the prosthesis.
• FIG. 7E depicts a particularly useful arrangement for configuring the belt end loops[0105]81-83 with release wires24-25 during assembly ofdelivery system10. In this example, first andsecond end loops81′ and81″ ofbelt21 are shown connected viarelease wire24. To achieve the configuration of FIG. 7E,first end loop81′ is passed throughaperture88 disposed insecond end loop81″. A portion ofaperture89 disposed infirst end loop81′ should extend through the plane created bysecond end loop81″ as shown in FIG. 7E.
• Next,[0106]release wire24 is passed through the portion ofaperture89 that extends beyond this plane so thatwire24 “locks” the two looped ends81′ and81″ together as shown. We have found that this is a stable configuration that lends itself well to a reliable and safe deployment protocol.
• Other techniques for assembling[0107]wire24 and first andsecond end loops81′ and81″ may be used; the method described above is merely exemplary.Wire24 may simply pass through loop ends as configured and as shown atreference numerals81,82 and83 in FIG. 7A, and81B,82B and83B of FIG. 7B as well.
• In the embodiment of FIG. 7F,[0108]belt110 is a member in the shape of a wire formed into anend loop116B having anaperture120 for receiving a release wire. This arrangement may be used on one or both ends ofbelt110 or, alone ifbelt110 is in the form of a single belt arm as discussed above.Connection123 is shown in FIG. 7F as a simple wrapping of the distal end116A of thewire comprising belt110.Connection123 need not be limited to such a tapered or cylindrical sleeve or coating, however. Other methods to formend loop116B are contemplated, including, for example, the use of adhesives, welding, brazing, soldering, crimping, etc. An optional protective sleeve or coating127 (shown in sectional view in FIG. 7F) covers or is part ofconnection123 and serves to protect the patient as well as components of the delivery system and prosthesis from damage.
• Turning now to FIGS. 7G and 7H, two alternative embodiments of a ribbon-[0109]like belt81G and81H are shown. In FIG. 7G, asection128 of material has been partially displaced frombelt81G distal end116C and worked into a loop-like member129 such that two generallyorthogonal apertures130,132 are formed in belt distal end116C. A set of hinges or other protective mechanism or material may be used on each end of thismember128 so that further tearing or peeling of this member may be prevented.Section128 may be formed integrally from the belt distal end116C as shown in FIG. 7G or may be a separate component that is attached to the belt distal end by any suitable means.
• Second belt distal end[0110]118C in FIG. 7G is shown as having anaperture133 disposed therein. In use, a half-twist is imparted to the ribbon-like belt81G as the second distal end118C is brought throughaperture130 such thatapertures132 and133 are at least partially aligned. A release wire (such as wire24) is then brought throughapertures132 and133 to releasably join ends116C and118C.
• FIG. 7H shows yet another embodiment of a[0111]belt81H where a simple rectangular aperture133A is disposed in thedistal end117 ofbelt81H through which another belt end and release wire may be disposed as taught herein. As with the embodiment of FIG. 7G, a half-twist is imparted to thebelt81H in use so that the seconddistal end118D is brought throughaperture133. A release wire may then be threaded throughapertures132 and133 to releasably join ends117 and118D. In this embodiment,aperture132 should be large enough to accommodate both seconddistal end118D and a release wire.
• FIG. 7I shows a perspective view of a belt assembly similar to that shown in FIG. 7A, wherein like elements are shown with like reference numerals. An alternative embodiment of a release wire consisting of a branched[0112]release wire150 is illustrated in FIG. 71. The branchedrelease wire150 engages belts21-23 and is configured to release belts21-23 at different times with a proximal withdrawal movement of the branchedrelease wire150, the direction of which is indicated byarrow151.Branched release wire150 has amain portion152 and abranch portion153.Branch portion153 is secured tomain portion152 by asolder joint154. The joint154 could also be made by any other suitable means, such as welding, bonding with an epoxy, mechanically binding the joint, or the like. The embodiment of the branched release wire shown in FIG. 7I consists of wire which is generally round in cross section. The wire of the branched release wire can have the same or similar material and mechanical properties to the wire of therelease wires24 and25 discussed above.Branch portion153 engages firstdistal belt21 and seconddistal belt22. Adistal segment155 has a length L indicated byarrow156 which extends distally from firstdistal belt21 to thedistal end157 ofbranch portion153.
• [0113]Main portion152 of the branchedrelease wire150 engages theproximal belt23 and has adistal segment158 that extends distally from theproximal belt23 to adistal end161 of the main portion. The length L′ of thedistal segment158 of themain portion152 is indicated byarrow162. Length L ofdistal segment155 is greater than length L′ ofdistal segment158. In this way, as the branched release wire is withdrawn proximally,proximal belt23 is released first, firstdistal belt21 is released second and second distal belt is released last. Such a branched release wire allows a wide variety of belt release timing with a single continuous withdrawal or movement of a proximal end (not shown) of the branchedrelease wire150. The proximal end of the branched release wire may be terminated and secured to a release wire handle or the like, as discussed herein with regard to other embodiments of release wires. The ability to deploy multiple release wires in a desired timing sequence with a singlebranched release wire150 gives the designer of the delivery system great flexibility and control over the deployment sequence while making the deployment of the belts simple and reliable for the operator of the delivery system. Although the branchedrelease wire150 has been shown with only a single branch, any number of branches or desired configuration could be used to achieve the deployment sequence required for a given embodiment of a delivery system. For example, a separate branch could be used for each belt in a multiple belt system, with varying distal segment length used to control the sequence of deployment. Also, multiple branched release wires, or the like, could be used in a single delivery system to achieve the desired results.
• A number of embodiments for the belt and belt arm components of the present invention are described herein. In general, however, we contemplate any belt or belt arm configuration in which the belt may be used to releasably hold or restrain an implant member in conjunction with a release member. The particular embodiments disclosed herein are not meant to be limiting, and other variations not explicitly disclosed herein, such as those in which multiple apertures (which may have varying shapes and sizes) are disposed along the belt length, those in which the belt or belt arm distal ends comprises a separate material or element that is affixed to the belt or belt arm, etc. are within the scope of the invention. Furthermore, various embodiments of the ends of the belts or belt arms taught herein may exist in any combination in a single delivery system.[0114]
• Turning now to FIG. 6A, belts[0115]21-23 lie within circumferential grooves orchannels95,96 and97, respectively, formed into the respective self-expandingmembers31,32 and33. Grooves95-97 prevent axial displacement of the belts21-23 prior to activation or release of thereleasable members24 and25, i.e., proximal retraction of the first and second release wires. Although grooves95-97 are illustrated in the embodiment shown, other alternatives are possible to achieve the same or similar function of the grooves. For example, abutments extending slightly from the self-expanding members31-33 on either side of the belts21-23 in their constraining configuration could prevent axial movement of the belts. A detachable adhesive or the like could also be used.
• As shown in FIG. 10, the release of end loops[0116]81-83 occurs when thedistal end portions84 and85 of therelease wires24 and25, respectively, pass from within the overlapped end loops81-83. If the end loops81-83 move axially in response to movement of therelease wires24 and25 due to frictional forces imposed on the end loops81-83 by the release wires, the point at which the distal ends of therelease wires84 and85 pass from within the end loops81-83 would vary depending on the amount of movement of the end loops81-83.
• If the end loops[0117]81-83 were to be axially displaced from their normal position relative to the distal ends of the release wires prior to deployment, the timing of the release of the belts21-23 could be adversely affected. Thus, the prevention of axial displacement of the belts21-23 during proximal retraction of therelease wires24 and25 facilitates accurate release of the belts by keeping the overlap joint of the belt looped end portions in a constant axial position during such retraction.
• In addition, it may be desirable to keep belts[0118]21-23 positioned at or near the general center of a given constrained self-expanding members31-33 so that the self-expanding member31-33 is substantially uniformly and evenly constrained over its axial length. If belts21-23 constrain the self-expanding members31-33 at a non-centered axial position on the member, an end of the member opposite that of the non-centered position may be less constrained and may interfere with axial movement of the outer tubular member53 (and consequently deployment of the endovascular graft11).
• [0119]Tubular body member205 of theendovascular graft11 is disposed between and secured to the second distal self-expandingmember33 and the proximal self-expandingmember31. The tubular body member comprised offlexible material204, is shown constrained in an idealized view in FIGS. 1, 3 and6, for clarity. In practice,tubular body member205 while constrained is tightly compressed with minimal air space between layers offlexible material204 so as to form a tightly packed configuration as shown in FIG. 3.Tubular body member205 is optionally radially constrained by aninside surface206 of theinner lumen52 of outertubular member53.
• An inner[0120]tubular member207 is slidably disposed within theinner lumen52 of outertubular member53.Release wires24 and25,guidewire tube17 and aninflation tube211 are disposed within aninner lumen212 of the innertubular member207.Inner lumen212 is optionally sealed with a sealing compound, depicted in FIGS. 1, 2 and6 byreference numeral213 atdistal end214. The sealingcompound213 prevents leakage of fluids such as blood, etc., from aproximal end215, shown in FIG. 8, of the innertubular member207. Sealingcompound213 fills the space within theinner lumen212 of the innertubular member207 between anouter surface216 of theguidewire tube17, theouter surface217 of theinflation tube211 andouter surfaces221 and222 of atubular guide223 for thefirst release wire24 and atubular guide224 for thesecond release wire25. The sealingcompound213 can be any suitable material, including epoxies, silicone sealer, ultraviolet cured polymers, or the like.
• In FIG. 2, the tubular guides[0121]223 and224 for thefirst release wire24 and thesecond release wire25 allow axial movement of the release wires with respect to the sealingcompound213 and innertubular member207. The inside diameter of the inner lumens of the tubular guides223 and224 are sized to fit closely with an outer diameter or transverse dimension of therelease wires24 and25. Alternatively, tubular guides223 and224 may be replaced by a single tubular guide that houses one or more release wires, such aswires24 and25.
• Turning to FIG. 8, the inner[0122]tubular member207 terminates proximally with theproximal adapter42 having a plurality ofside arms225,226 and227 and aproximal exit port231 for theinner lumen34 of theguidewire tube17. First releasewire side arm225 branches from a proximaladapter body portion233 and has aninner lumen234 andproximal end86 of thefirst release wire24. Aproximal extremity236 of thefirst release wire24 is anchored to the first release wireproximal handle93 which is threaded onto theproximal end238 of the first releasewire side arm225. Theproximal extremity236 offirst release wire24 is configured as an expanded bushing or other abutment that captures thehandle93 and translates proximal axial movement of thehandle93 to thefirst release wire24 but allows relative rotational movement between thehandle93 and theproximal end86 of thefirst release wire24.
• A similar configuration exists for the[0123]proximal end87 of thesecond release wire25. There, a second releasewire side arm226 branches from the proximaladapter body portion233 and has aninner lumen244 that houses theproximal end87 of thesecond release wire25 which is free to slide in an axial orientation within thelumen244. Aproximal extremity246 of thesecond release wire25 is configured as an expanded bushing or other abutment that captures the second release wire handle and translates axial proximal movement of the second release wire handle94 to thesecond release wire25, but allows relative rotational movement between theproximal end87 of thesecond release wire25 and the second release wire handle94.
• The first release wire handle[0124]93 and second release wire handle94 may optionally be color coded by making each, or at least two, release wire handles a color that is distinctly different from the other. For example, the first release wire handle93 could be made green in color with the second release wire handle94 being red in color. This configuration allows the operator to quickly distinguish between the two release wire handles and facilitates deployment of the belts in the desired order.
• In another embodiment, instead of color coding of the release wire handles[0125]93 and94, the spatial location of the handles can be configured to convey the proper order of deployment of the release wires to the operator of the delivery system. For example, if three release wire handles are required for a particular embodiment, the corresponding three side arms can be positioned along one side of the proximal adapter. In this configuration, the release wire handle that needs to be deployed first can extend from the distal-most side arm. The release wire handle that needs to be deployed second can extend from the middle side arm. The release wire handle that is to be deployed last can extend from the proximal-most side arm. For such a configuration, the operator is merely instructed to start deployment of the release wires at the distal-most release wire handle and work backward in a proximal direction to each adjacent release wire handle until all are deployed. Of course, an opposite or any other suitable configuration could be adopted. The configuration should adopt some type of spatially linear deployment order, either from distal to proximal or proximal to distal, in order to make reliable deployment of the release wires in the proper order easy to understand and repeat for the operator of the delivery system. Other types of release order indicators such as those discussed above could also be used, such as numbering each release wire handle or side arm with a number that indicates the order in which that handle is to be deployed.
• The[0126]proximal end36 of theguidewire tube17 terminates and is secured to aninner lumen251 of theproximal end259 of theproximal adapter42.Inner lumen251 typically has alongitudinal axis253 that is aligned with alongitudinal axis254 of theproximal section13elongate shaft12 so as to allow a guidewire to exit theproximal end15 of theelongate shaft12 without undergoing bending which could create frictional resistance to axial movement of the guidewire. Aproximal port255 of theproximal adapter42 may be directly fitted with a hemostasis valve, or it may be fitted with a Luer lock fitting which can accept a hemostasis valve or the like (not shown).
• The[0127]proximal adapter42 may be secured to theproximal end215 of the innertubular member207 by adhesive bonding or other suitable method. Astrain relief member256 is secured to thedistal end257 of theproximal adapter42 and the innertubular member207 to prevent kinking or distortion of the innertubular member207 at the joint.
• As seen in FIG. 1, the[0128]proximal end261 of the outertubular member53 is secured to aproximal fitting262 that slides over anouter surface258 of the innertubular member207. Aseal263 located inproximal fitting262 provides a fluid seal for thelumen265 formed between theouter surface258 of the innertubular member207 and theinner surface206 of theinner lumen52 of the outertubular member53. The fit between theouter surface258 of the innertubular member207 and theinner surface206 of the outertubular member53 is typically close, but still allows for easy relative axial movement between outertubular member53 and innertubular member207. Astop266 is disposed and secured to theouter surface258 of the innertubular member207 distal of theproximal adapter42 to limit the amount of proximal axial movement of the outertubular member53 relative to the innertubular member207.
• When the outer[0129]tubular member53 is positioned on theproximal shoulder48 of thedistal nose piece44 prior to deployment ofendovascular graft11, the distance between aproximal extremity267 ofproximal fitting262 and adistal extremity268 ofstop266 is approximately equal to or slightly greater than an axial length of theendovascular graft11 in a constrained state. This configuration allows the outertubular member53 to be proximally retracted to fully expose theendovascular graft11 in a constrained state prior to deployment of the graft. This distance may be greater, but should not be less than the length of theendovascular graft11 in a constrained state in order to completely free theconstrained graft11 for radial expansion and deployment.
• Retraction limiters may alternatively be used to prevent excessive axial movement of the[0130]release wires24 and25 in a proximal direction during deployment. Particularly in embodiments of the invention where single release wires are used to constrain and deploy multiple belts such as withfirst release wire24, retraction limiters may be used to allow enough axial movement of therelease wire24 to deploy afirst belt21, but prevent deployment of a second more proximally locatedbelt22. For example, as shown in FIG. 8, a retraction limiter in the form of afilament268 could be disposed between theproximal adapter42 and thehandle93 of thefirst release wire24 such that proximal retraction of thefirst release wire24 sufficient for deployment of the firstdistal belt21 could be achieved, but not so much as to allow deployment of the seconddistal belt22. In order to deploy the seconddistal belt22, thefilament268 would have to be severed or otherwise released. This type of configuration can allow more control over deployment of theendovascular graft11 and allow deployment in stages which are sequentially controlled to prevent inadvertent deployment of a portion of thegraft11 in an undesirable location within the patient's vessels.
• In use, the[0131]delivery system10 is advanced into a patient'sarterial system271 percutaneously as shown in FIG. 9 and positioned so that theendovascular graft11 spans ananeurysm272 in the patient'saorta45 as20 illustrated in FIGS. 1 and 9-12. It is generally desirable to have thetubular body portion205 of thegraft11 positioned below the renal arteries273 in order to prevent significant occlusion of the renal arteries.
• The procedure typically begins with the placement of[0132]guidewire18 into the patient'starget vessel45 across the target location, e.g., theaneurysm272. Common percutaneous techniques known in the art may be used for the initial placement of theguidewire18. For example, as shown in FIG. 9, percutaneous access to the aorta may be had through the femoral or iliac artery, although other access sites may be used. Thedelivery system10 may then be advanced over theguidewire18 to a desired position within the patient'svessel45. Alternatively,delivery system10 and guidewire18 could be advanced together into the patient'svasculature272 with theguidewire18 extending distally from thedistal port38 of theguidewire tube17. In addition, it may be desirable in some cases to advance thedelivery system10 to a desired location within the patient without the use of aguidewire18. Generally, the position of thedelivery system10 is determined using fluoroscopic imaging or the like. As such, it may be desirable to have one or more radiopaque markers (not shown) secured to the delivery system at various locations. For example, markers may be placed longitudinally coextensive with the respective distal andproximal extremities274 and275, as shown in FIG. 11. In this way, it can be readily determined whether thegraft11 is spanning theaneurysm272 of the patient's artery. Imaging markers, such as radiopaque markers, may also be secured to desirable positions on theendovascular graft11 itself. Other types of imaging and marking systems may be used such as computed tomography (CT), magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) imaging systems and markers.
• Once the[0133]distal section14 of thedelivery system10 is properly positioned within the patient'sartery45, the operator moves theproximal end261 of outertubular member53 in a proximal direction relative to innertubular member207. The relative axial movement is carried out by grasping theproximal end215 of the innertubular member207 orproximal adapter42, and grasping theproximal end261 of the outertubular member53, and moving the respective proximal ends towards each other. This retracts thedistal section276 of the outertubular member53 from the constrainedendovascular graft11 and frees the graft for outward radial expansion and deployment. However, in this deployment scheme, note that the operator is free to reinsertgraft11 back into the outertubular member53 if necessary, as the release bands have not yet released the graft.
• Once the[0134]distal section276 of the outertubular member53 has been retracted, handle93 of thefirst release wire24 may then be unscrewed or otherwise freed from theproximal adapter42 and retracted in a proximal direction indicated byarrow279 in FIG. 10 until thedistal end84 of thefirst release wire24 passes from within theend loops81 of the firstdistal belt21. When this occurs, the looped ends81 of the firstdistal belt21 are released and the firstdistal belt21 ceases to radially constrain the first distal self-expandingmember32 which thereafter self-expands in a radial direction into aninner surface278 of the patient'saorta45 as shown in FIG. 10.
• If the operator of the[0135]delivery system10 is not satisfied with the position, particularly the axial position, of theendovascular graft11 after deployment of the first distal self-expandingmember32, it may then be possible to re-position theendovascular graft11 by manipulating theproximal end15 of theelongate shaft15. Movement of theelongate shaft12 can move theendovascular graft11, even though physical contact between the expandedmember32 and the vesselinner surface278 generates some static frictional forces that resist such movement. It has been found that theendovascular graft11 can be safely moved within ablood vessel45 even in the state of partial deployment discussed above, if necessary.
• Once the operator is satisfied with the position of the[0136]graft11, thefirst release wire24 may then be further proximally retracted so as to deploy the seconddistal belt22 in a manner similar to the deployment of the firstdistal belt21. The deployment of the seconddistal belt22 occurs when thedistal end84 of thefirst release wire24 passes from withinend loops82 of the seconddistal belt22 which are held in a radially constraining configuration by thefirst release wire24. Upon release of the seconddistal belt22, the second distal self-expandingmember33 expands in a radial direction such that it may engageinner surface278 of the patient'saorta45. The amount of outward radial force exerted by the self-expandingmembers32 and33 on theinside surface278 of the patient'saorta45, which may vary betweenmembers32 and33, is dependent upon a number of parameters such as the thickness of the material which comprises the self-expandingmembers32 and33, the nominal diameter which the self-expandingmembers32 and33 would assume in a free unconstrained state with no inward radial force applied, material properties of the members and other factors as well.
• Once the[0137]distal members32 and33 are deployed, thehandle94 for thesecond release wire25 can be disengaged and axially retracted in a proximal direction from theproximal adapter42 until thedistal end85 of thesecond release wire25 passes from within theend loops83 of theproximal belt23. Once theproximal belt23 is released, the proximal self-expandingmember31 is deployed and expands in an outward radial direction, such that it may engage or be in apposition with theinner surface278 of the patient'saorta45 as shown in FIG. 11. Thereafter, theendovascular graft11 may be inflated with an inflation material (not shown) introduced into theproximal injection port282 in theproximal adapter42, through theinflation tube211, and into theinflation port283 of theendovascular graft11. Inflation material may be injected or introduced into theinflation port283 until the proximal and distalinflatable cuffs28 and30 andinflatable channels284 of thegraft11 have been filled to a sufficient level to meet sealing and other structural requirements necessary for the tubular body to meet clinical performance criteria.
• Before or during the deployment process, and preferably prior to or simultaneous with the step of inflating the[0138]endovascular graft11, it may be beneficial to optionally treatvessel45 in which thegraft11 is deployed so to obtain a better seal between thegraft11 and the vesselinner surface278, thus improving the clinical result and helping to ensure a long term cure.
• One approach to this treatment is to administer a vasodilator, or spasmolytic, to the patient prior to deploying[0139]graft11. This has the effect of reducing the tone of the smooth muscle tissue in the patient's arteries; specifically, the smooth muscle tissue in the wall ofvessel45 into whichgraft11 is to be deployed. Such tone reduction in turn induces the dilation ofvessel45, reducing the patient's blood pressure. Any number of appropriate vasoactive antagonists, including the direct acting organic nitrates (e.g., nitroglycerin, isosorbide dinitrate, nitroprusside), calcium channel blocking agents (e.g., nifedipine), angiotensin-converting enzyme inhibitors (e.g., captopril), alphaadrenergic blockers (e.g., phenoxybenzamine, phentolamine, prasozin), beta-adrenergic blockers (e.g., esmolol) and other drugs may be used as appropriate. Particularly useful are those vasodilators that can be administered intravenously and that do not have unacceptable contraindications such as aoritic aneurysm dissection, tachycardia, arrhythmia, etc.
• The degree of vasodilatation and hypotensive effect will depend in part on the particular vessel in which[0140]graft11 is to be placed and the amount of smooth muscle cell content. Generally, the smaller the vessel, the larger percentage of smooth muscle cell present and thus the larger effect the vasodilator will have in dilating the vessel. Other factors that will effect the degree of vasodilatation is the health of the patient; in particular, the condition of thevessel11 into whichgraft11 is to be placed.
• In practice, once the vasodilator has been administered to the patient,[0141]graft11 may be deployed and filled with inflation material so thatgraft11 reaches a larger diameter than would otherwise be possible if such a vasodilator was not used. This allows the inflation material to expand the diameter ofgraft11, for a given inflation pressure, beyond that which would be achievable if thevessel45 were in a non-dilated state (and nominal diameter). Alternatively, alarger diameter graft11 may be chosen for deployment. We anticipate that an increased vessel diameter of between two and twenty percent during vasodilatation may be optimal for achieving an improved seal.
• The[0142]vessel45 in whichgraft11 is to be placed may optionally be monitored pre- and/or post-dilation but before deployment of graft11 (via computed tomography, magnetic resonance, intravenous ultrasound, angiography, blood pressure, etc.) so to measure the degree of vasodilatation or simply to confirm that the vasodilator has acted on thevessel45 prior to deployinggraft11.
• Once the vasodilator wears off, preferably after between about five and thirty minutes from the time the drug is administered, the[0143]vessel45 surroundinggraft11 returns to its normal diameter. The resultant graft-vessel configuration now contains an enhanced seal betweengraft11 and vesselinner surface278 and provides for reduced luminal intrusion bygraft11, presenting an improved barrier against leakage and perigraft blood flow compared to that obtainable without the sue of vasodilators or the like.
• Such vasodilating techniques may be used with all of the embodiments of the present invention, including the[0144]tubular graft11 as well as a bifurcated graft version of the expandable intracorporeal device of the present invention as is discussed in detail below.
• Once[0145]graft11 is fully deployed, a restraining or retention device, such asretention wire285 that binds thedistal end286 of the inflation tube111 to theinflation port283, as shown in FIGS. 12 and 13, is activated. Theretention wire185 is activated by pulling the proximal end of the wire in a proximal direction so as to disengage the distal ends293 and294 from theholes295 and296. This eliminates the shear pin function of the distal ends293 and294 and allows thedistal end286 of theinflation tube211 to be disengaged from theinflation port283. Therelease wires24 and25 may then be fully retracted from theelongate shaft12 in a proximal direction and thedelivery system10 retracted in a proximal direction from the deployedendovascular graft11. The unconstrained distal belts21-23 slip through the openings in the expandedmembers31,32 and33 as thedelivery system10 is retracted and are withdrawn through theinner passageway287 of the deployedgraft11. Thedistal nosepiece44 is also withdrawn through theinner passageway287 of the deployedgraft11 as thedelivery system10 is withdrawn as shown in FIG. 10-12.
• FIG. 13 illustrates the junction between the[0146]distal end286 ofinflation tube211 andinflation port283. Typically,retention wire285 extends from theinflation port283 proximally to theproximal end15 ofdelivery system10. In this way, an operator can disengage thedistal end286 of theinflation tube211 from theinflation port283 by pulling on theproximal end283 ofretention wire285 from aproximal end15 ofdelivery system10. Theretention wire285 can be a small diameter wire made from a material such as a polymer, stainless steel, nickel titanium, or other alloy or metal; in a particular embodiment of the invention,retention wire285 may be a spring formed of a variety of suitable spring materials. Alternativelyretention wire285 may have a braided or stranded configuration.
• FIG. 13 shows a single retention filament or[0147]wire285 disposed within thelumen291 of theinflation tube211. Thedistal end292 ofretention wire285 may have one ormore loops293 and294, respectively, disposed within one or more side holes disposed in theinflation port283 of thedistal end286 of theinflation tube211. A number of side hole configurations may be utilized. The embodiment of FIG. 13 has two sets of opposedside hole locations295 and296. Thedistal loops293 and294 of theretention wire285 act to interlock the side holes295 and296 by creating a removable shear pin element which prevents relative axial movement between thedistal end286 of theinflation tube211 and theinflation port283. Alternate embodiments may include multiple retention filaments or wires disposed within thelumen291 of theinflation tube211. An external sleeve (not shown) may be added over this assembly to further secure the interface and prevent leakage of inflation material throughside holes295 and296. This sleeve is attached toinflation tube211 and is received with it.
• FIGS.[0148]14-17 illustrate an alternative embodiment of the delivery system shown in FIG. 1. In FIGS.14-17, like elements with respect to the embodiment of FIG. 1 will be shown with like reference numerals where appropriate. Thedelivery system300 has anouter tubular member53 and innertubular member207 at adistal section303 of thedelivery system300. Anendovascular graft11 is disposed within the outer tubular member in thedistal section303. Aninflation tube305, similar to that of the embodiment shown in FIG. 1 is coupled to aninflation port283 of theendovascular graft11. However, theinflation tube305, having aproximal end307 and adistal end308, does not extend the majority of the length of thedelivery system300. Instead, theproximal end307 of theinflation tube305 terminates at aproximal end311 of thepotted section213 as shown in FIGS.14 -16.
• Referring to FIG. 14 and[0149]16,first release wire312 havingdistal end313 engagesend loops82 of seconddistal belt22. The seconddistal belt22 is disposed about and constrains the second distal self-expandingmember33. Asecond release wire316 having adistal end317 engages theend loops81 of the firstdistal belt21 and theend loops83 of theproximal belt23. The firstdistal belt21 is disposed about and constrains the first distal self-expandingmember32. Theproximal belt23 is disposed about and constrains the proximal self-expandingmember31. Arelease wire tube318, having aproximal end321, as shown in FIG. 17, and adistal end322, shown in FIG. 16, extends from thepotted section213 of thedistal section303 of thedelivery system300 to theproximal adapter323 shown in FIG. 17. Therelease wire tube318 has alumen324, as shown in FIG. 15, which contains thefirst release wire312 and thesecond release wire316.
• The[0150]proximal adapter323 has afirst side arm324 with aninner lumen325 that secures theproximal end321 of therelease wire tube318. A threadedend cap326 is secured to aproximal end327 of thefirst side arm324 and has a threadedportion328. A secondrelease wire handle331, having a distal threadedportion332 and a proximal threadedportion333, is threaded onto the threadedend cap326. Aproximal end334 of thesecond release wire316 is secured to the secondrelease wire handle331. A first release wire handle335 has a threadedportion336 that is releasably threaded onto the proximal threadedportion333 of the secondrelease wire handle331. Aproximal end337 of thefirst release wire312 is secured to the firstrelease wire handle335.
• Once the outer[0151]tubular member53 has been proximally retracted, belts21-23 can be released. This configuration allows the operator of thedelivery system300 to first disengage and proximally retract the first release wire handle335 so as to first release the second distal self-expandingmember33 without releasing or otherwise disturbing the constrained state of the first distal self-expandingmember32 or the proximal self-expandingmember31. Once the second distal self-expandingmember33 has been deployed or released, theendovascular graft11 may be axially moved or repositioned to allow the operator to adjust the position of thegraft11 for final deployment.
• This is advantageous, particularly in the treatment of abdominal aortic aneurysms, because it allows the physician to accurately place[0152]graft11 into position. In many cases, it is desirable for the physician to place thegraft11 such that the distal end of thetubular body portion205 of the graft is just below the renal arteries273, shown in FIG. 9, to prevent occlusion of the renal arteries by thetubular body portion205. If a self-expanding member, such as self-expandingmember32 is radiopaque and the delivery procedure is performed using fluoroscopic imaging, adjustment of the position of the graft after release of self-expanding member is readily achievable. Because self-expandingmember32 is immediately adjacent the distal end of thetubular body portion205 of thegraft11, the ability to visualize and reposition the self-expandingmember32 is particularly useful in order to position the distal end of thetubular body portion205 just below the renal arteries without occluding the renal arteries, if such positioning is indicated for the patient being treated.
• Thereafter, the second release wire handle[0153]331 may be unscrewed or otherwise released from theend cap326 and proximally retracted so as to first release the first distalbelt end loops81 and then the proximalbelt end loops83. Of course, the position of thegraft11 may still be adjustable even with both distal self-expandingmembers32 and33 deployed, depending on the particular configuration of thegraft11 and the self-expandingmembers32 and33. The release of thebelts21,22 and23 is the same or similar to that of the belts of the embodiment of FIG. 1 and occurs when the distal end of therelease wires313 and317 which lock the end loops81-83 together is proximally retracted past the end loops81-83 of the belts21-23 which are constrained.
• Once the self-expanding members[0154]31-33 of theendovascular graft11 have been deployed or released, and thegraft11 is in a desired location, thegraft11 can then be inflated by injection of an inflation material (not shown) into theinjection port338 on asecond side arm341 of theproximal adapter323. The inflation material is introduced or injected directly into aninner lumen212 of the innertubular member207, as shown in FIG. 17, and travels distally between aninside surface342 of the innertubular member207, outsidesurface343 of therelease wire tube318 and outsidesurface216 of theguidewire tube17. This allows the inflation material, which can be highly viscous, to flow through the cross sectional area between theinside surface342 of the innertubular member207 and theoutside surfaces216 and343 of therelease wire tube318 andguidewire tube17. This cross sectional area is large relative to the cross sectional area of the inner lumen of theinflation tube211 of the embodiment of FIG. 1. This results in more rapid flow of inflation material to theinflatable cuffs28 and30 andchannels284 of theendovascular graft11 and decreases inflation time.
• Once the inflation material, which is travelling distally in the[0155]delivery system300 during inflation, reaches the pottedportion213 of thedistal section303 of the delivery system, it then enters and flows through alumen344, as shown in FIG. 16, at theproximal end307 of theinflation tube305 and into theinflation port283 of thegraft11. Upon inflation of thegraft11 with an inflation material, a release device, such asretention wire285 can be retracted or otherwise activated so as to de-couple theinflation tube305 from theinflation port283 of theendovascular graft11.
• A[0156]proximal end36 of theguidewire tube17 is secured within acentral arm345 of theproximal adapter323 that has a pottedsection346. Aseal349 is disposed on aproximal end347 of thecentral arm345 for sealing around theguidewire18 and preventing a backflow of blood around the guidewire. A hemostasis adapter (not shown) can be coupled to theproximal end347 of thecentral arm345 in order to introduce fluids through theguidewire tube lumen348, as shown in FIG. 15, around an outside surface of theguidewire18. Thepotted section346 of thecentral arm345 prevents any fluids injected through the hemostatis adapter from passing into theinflation material lumen351 within theproximal adapter323 or the innertubular member207.
• FIG. 18 illustrates an alternative embodiment to the[0157]proximal adapters42 and323 used in the embodiments of the invention of FIG. 1 and FIG. 14. In this embodiment, theproximal adapter360 has a first release wire handle361 and a second release wire handle362 which are in a nested configuration. Theproximal end334 of thesecond release wire316 is secured to the secondrelease wire handle362. Theproximal end337 of thefirst release wire312 is secured to the firstrelease wire handle361. This configuration prevents the operator from inadvertently deploying or activating thesecond release wire316 prior to deployment or activation of thefirst release wire312 which could result in an undesirable endovascular graft deployment sequence.
• In use, the operator first unscrews or otherwise detaches a threaded[0158]portion363 of the first release wire handle361 from an outer threadedportion364 of a first sidearm end cap365 of afirst side arm366. The first release wire handle361 is then proximally retracted which releases theend loops82 of the seconddistal belt22 as discussed above with regard to the embodiment of the invention shown in FIG. 14.
• Once the first release wire handle[0159]361 is removed from the first sidearm end cap365, the second release wire handle362 is exposed and accessible to the operator of the delivery system. A threadedportion367 of the second release wire handle362 can then be unscrewed or otherwise detached from an inner threadedportion368 of the first sidearm end cap365. The second release wire handle362 can then be retracted proximally so as to sequentially deploy the firstdistal belt21 and self-expandingmember32 andproximal belt23 and proximal self-expandingmember31, respectively. The other functions and features of theproximal adapter360 can be the same or similar to those of theproximal adapters42 and323 shown in FIG. 1 and FIG. 17 and discussed above.
• Optionally, this embodiment may comprise reverse or oppositely threaded portions,[0160]363 and367 respectively, of the first and second release wire handles361 and362. Thus, for instance, a counter-clockwise motion may be required to unthread threadedportion363 of the first release wire handle361 from the outer threadedportion364, while a clockwise motion is in contrast required to unthread threadedportion367 of the second release wire handle367 from the inner threadedportion368. This feature serves as a check on the overzealous operator who might otherwise prematurely unscrew or detach the threadedportion367 of the second release wire handle362 by unscrewing in the same direction as required to release the threadedportion363 of the firstrelease wire handle361.
• In another aspect of the invention, a[0161]delivery system400 for delivery and deployment of a bifurcated intracorporeal device, specifically, an embodiment of the invention directed to delivery and deployment of a bifurcated endovascular graft or stent is contemplated. As with all the delivery systems disclosed herein, thedelivery system400 for a bifurcated device is configured for delivery and deployment a wide variety of intracorporeal devices. Although the focus of the specific embodiments are directed to systems for delivery of endovascular grafts or stent grafts, embodiments of the delivery systems disclosed herein can are also suitable for delivery of intravascular filters, stents, including coronary stents, other types of shunts for intracorporeal channels, aneurysm or vessel occluding devices and the like.
• The structure, materials and dimensions of the[0162]delivery system400 for bifurcated devices can be the same or similar to the structure, materials and dimensions of the delivery systems discussed above. In addition, the structure, materials and dimensions of bifurcated grafts contemplated herein can have structure, materials and dimensions similar to those of grafts having a primarily tubular shape discussed above.
• FIGS.[0163]19-22 illustrate an embodiment of an expandable intracorporeal device in the form of a bifurcated stent-graft401. This embodiment includes amain body portion402 at adistal end403 of thegraft401 that has a generally tubular cross-sectional profile when the graft takes on an expanded or deployed configuration. Anipsilateral leg404 and contralateral leg405 (short leg), both having a substantially tubular configuration when expanded or deployed, branch from themain body portion402 atbifurcation406 and extend in a proximal direction from thebifurcation406. Theipsilateral leg404 terminates proximally with a proximal self-expandingmember407 and thecontralateral leg405 terminates proximally with a proximal self-expandingmember408.
• The[0164]main body portion402 of the graft may have a transverse dimension when in an expanded or deployed state ranging from about 10 mm to about 40 mm, specifically from about 15 mm to about 30 mm.
• The[0165]legs404 and405 of thegraft401 may have a transverse dimension when in an expanded or deployed state ranging from about 5 mm to about 16 mm, specifically from about 8 mm to about 14 mm. Themain body portion402 of thegraft401 may have a length ranging from about 2 cm to about 12 cm, specifically from about 4 cm to about 8 cm.
• A second distal self-expanding[0166]member411 is disposed at adistal end412 of themain body portion402 of thegraft401 as with the graft embodiments previously discussed. Also, as with other endovascular graft embodiments discussed herein, thegraft401 may have inflatable channels and inflatable cuffs that serve, among other functions, to provide support for thegraft401 and the inflatable channels and cuffs can have configurations which are the same or similar to those inflatable channels and cuffs of other graft embodiments discussed herein, as well as other configurations. A distalinflatable cuff413 is disposed at thedistal end412 of themain body portion402. Proximalinflatable cuffs414 and415 are disposed on aproximal end416 of theipsilateral leg404 and aproximal end417 of thecontralateral leg405 respectively.Inflatable channels418 are fluid tight conduits which connect theinflatable cuffs413,414 and415. Theinflatable channels418 andinflatable cuffs413 and414 are inflatable through aninflation port421 that may be disposed at or near theproximal end416 of theipsilateral leg404. Theinflation port421 may also be disposed at or near theproximal end417 of thecontralateral leg405, or it may be disposed on other portions of the device as necessary. Generally, the structure and the materials used in the graft401 (both the graft portion and the self-expanding members) can be similar to the structure and materials of the other graft embodiments discussed above. In one particular embodiment, the main body portion and legs of the graft are made of expanded polytetrafluoroethylene (ePTFE) and the self-expanding members are made of nickel titanium, stainless steel or the like.
• A first distal self-expanding[0167]member422 is secured to the second distal self-expandingmember411 as shown in FIG. 19. This configuration is similar to that ofendovascular graft11 illustrated in FIGS.1-6B,10-12 and14-16 above.Graft11 has first and second distal self-expandingmembers32 and33 that may be deployed in any desired sequence. In a particular embodiment having first and second distal self-expanding members, it may be desirable to first deploy the second distal self-expandingmember33 prior to deploying the first distal self-expandingmember32. As discussed above, deploying the second distal self-expandingmember33 first may allow the operator to accurately adjust the axial position of the graft in the body lumen or vessel to within one to several millimeters before deploying the first distal self-expandingmember32. Using this technique, deployment of the second distal self-expandingmember33 alone provides sufficient resistance to axial displacement of thegraft11 for the graft position to be maintained in normal blood flow, but still allows deliberate axial displacement by the operator to achieve a desired axial position. This may be particularly important if tissue-penetrating members are included on the distal-most or first distal self-expandingmember32. If such tissue penetrating members are used on the first distal self-expandingmember32, axial movement may be difficult or even impossible once thismember32 is deployed without risking damage to the body lumen or vessel. As such, accurate axial placement of thegraft11 prior to deployment of the first distal self-expandingmember32 can be critical.
• In addition, although not shown in the figures, this[0168]graft embodiment401 may include two or more proximal self-expanding members disposed on one or both of theipsilateral leg404 and/orcontralateral leg405. These self-expanding members may have a configuration similar to that of the first and second distal self-expandingmembers411 and422
• FIGS.[0169]23-32 illustrate an embodiment of adelivery system400 having features of the invention. FIG. 23 showsdelivery system400 in partial section having anelongate shaft423 with aproximal end424, adistal end425 and adistal section426. Aproximal adapter427 is disposed at theproximal end424 of theelongate shaft423 and houses the controls that enable the operator to manipulate elements at thedistal section426 ofdelivery system400 to release and deploy thegraft401, including inflating thegraft channels418 andcuffs413,414 and415. Theelongate shaft423 has an innertubular member430 and an outertubular member431 disposed about the innertubular member430. The outertubular member431 is generally configured to slide in an axial direction over the innertubular member430. Aproximal end432 of the innertubular member430 is secured to or disposed on theproximal adapter427. The inner and outertubular members430 and431 may be made of polymeric materials, e.g., polyimides, polyester elastomers (HYTREL®), or polyether block amides (PEBAX®), and other thermoplastics and polymers. The outside diameter of the outertubular member431 may range from about 0.1 inch to about 0.4 inch; specifically from about 0.15 inch to about 0.20 inch. The wall thickness of the outertubular member431 may range from about 0.002 inch to about 0.015 inch, specifically from about 0.004 inch to about 0.008 inch. Theproximal adapter427 is generally fabricated from a polymeric material such as polyethylene, acetal resins (DELRIN®), etc., but can also be made from any other suitable material.
• [0170]Bifurcated stent graft401 is shown in FIGS.23-28 disposed within thedistal section426 of theelongate shaft423 in a constrained configuration. The outertubular member431 is disposed about thegraft401 in the constrained state but can be retracted proximally so as to expose theconstrained graft401 by proximally retracting a proximal end433 of the outertubular member431. As illustrated more fully in FIG. 37, adistal nosepiece434 may be disposed on adistal end435 of the outertubular member431 and forms a smooth tapered transition from aguidewire tube436 to the outertubular member431. This transition helps to facilitate the tracking of the outertubular member431 over aguidewire437. In order to form this smooth transition, thenosepiece434 may have a length to major diameter ratio ranging from about 3:1 to about 10:1 (the “major diameter” being defined as the largest diameter of the nosepiece). The outertubular member431 is not typically permanently secured to thenosepiece434 and may be retractable from thenosepiece434 during the deployment sequence. Asecondary release cable438 extends from an opening in the distal section of the elongate shaft.Nosepiece434 may be grooved to receivesecondary release cable438 if desired.
• FIG. 24 shows the inner[0171]tubular member430 disposed within the outertubular member431 and theguidewire tube436 disposed within the innertubular member430. Theguidewire tube436 may be made from polymeric materials such as polyimide, polyethylene, polyetheretherketones (PEEK®), or other suitable polymers, and may have an outside diameter ranging from about 0.02 inch to about 0.08 inch, specifically about 0.035 inch to about 0.055 inch. Theguidewire tube436 wall thickness may range from about 0.002 inch to about 0.025 inch, specifically from about0.004 inch to about 0.010 inch.
• A release member tube in the form of a[0172]release wire tube441 is disposed about a distal primary release member in the form of a distalprimary release wire442. Therelease wire tube441 is also disposed about a proximal primary release member in the form of a proximalprimary release wire443. Both therelease member tube441 and aninflation tube444 are disposed within aninner lumen445 of the innertubular member430. The outside diameter of therelease wire tube441 may range from about 0.01 inch to about 0.05 inch, specifically about 0.015 inch to about 0.025 inch. The wall thickness of therelease wire tube441 may range from about 0.001 inch to about 0.006 inch, specifically from about 0.002 inch to about 0.004 inch.
• The outside diameter of the[0173]inflation tube444 may range from about 0.02 inch to about 0.10 inch; specifically from about 0.04 inch to about 0.08 inch. Theinflation tube444 wall thickness may range from about 0.002 inch to about 0.025 inch; specifically from about 0.003 inch to about 0.010 inch.
• In FIG. 25, a[0174]potted portion446 is disposed between aninner surface447 of a distal end448 of the innertubular member430, therelease wire tube441, theguidewire tube436 and theinflation tube444. Thepotted portion446 seals theinner lumen445 of the innertubular member430 from bodily fluids that are exposed to theconstrained graft401 andpotted portion446 once the outertubular member431 is proximally retracted. Thepotted portion446 may be made from adhesives, thermoforming plastics, epoxy, metals, or any other suitable potting material. Alternatively, a molded or machined plug may be bonded or affixed to the distal end of the inner tubular member, with lumens to accommodate the passage oftubes441,436 and444.
• A more detailed view of the[0175]distal section426 of theelongate shaft423 is shown in partial section in FIGS.26-30. Adistal section451 of theguidewire tube436 serves as a primarybelt support member452 and is disposed within themain body portion402 andipsilateral leg404 of thegraft401. Alternatively, the primarybelt support member452 may be disposed adjacent the graftmain body portion402 andipsilateral leg404. A secondary beltsupport member housing453 is secured to the primarybelt support member452. An additional length of guidewire tube or other elongate member serving as a secondarybelt support member454 is slidably disposed within an appropriately configuredlumen455 of thehousing453. The secondarybelt support member454 is shown in FIG. 26 disposed within the graftmain body portion402 andcontralateral leg405; however, the secondarybelt support member454 may also be disposed adjacent thecontralateral leg405, regardless of whether the primarybelt support member452 is disposed adjacent or within themain body portion402 andipsilateral leg404.
• The secondary belt support[0176]member housing lumen455 andsecondary support member454 cross sections may be keyed, singly or in combination, to allow relative sliding motion without relative rotation motion and therefore limit any twisting of thesecondary support member454 and thecontralateral leg405. The secondarybelt support member454 may be made from alloys such as nickel titanium, stainless steel, or polymeric materials such as polyimide and can have an outside transverse dimension ranging from about 0.01 inch to about 0.06 inch.
• A proximal[0177]primary belt456 is shown in FIG. 26 disposed about and radially constraining the proximal self-expandingmember407 of theipsilateral leg404. This proximal self-expandingmember407 in turn is disposed about abushing457 that is shown as cylindrical in form, but which may have other configurations as well. Thebushing457 is secured to the primarybelt support member452 adjacent the proximal self-expandingmember407 of theipsilateral leg404.
• A first distal[0178]primary belt458 is disposed about and radially constraining the first distal self-expandingmember422, which itself is disposed about acylindrical bushing461. A second distalprimary belt462 is disposed about and radially constraining the second distal self-expandingmember411 and the second distal self-expandingmember411 is disposed about acylindrical bushing463.
• A[0179]secondary belt464 is shown disposed about and radially constraining the proximal self-expandingmember408 of thecontralateral leg405. This proximal self-expandingmember408 is disposed about abushing465 that is cylindrical in shape.
• As with the other embodiments of the present invention, the[0180]belts456,458,462 and464 are typically made from nickel titanium, an alloy that is capable of exhibiting a unique combination of high strain without elastic deformation, high strength and biocompatability. However, any other suitable materials may be used including other metallic alloys such as stainless steel, high strength fibers such as carbon, KEVLAR®, polytetrafluoroethylene (PTFE), polyimide, or the like. The outer transverse dimension or diameter of thebelts456,458,462 and464 can be from about 0.002 inch to about 0.012 inch; specifically about 0.004 inch to about 0.007 inch.
• A[0181]distal portion466 of the proximalprimary release wire443 is disposed withinend loops468 of the proximalprimary belt456 so as to releasably secure the proximal self-expandingmember407 of theipsilateral leg404 in a constrained state. The proximalprimary belt456 may be disposed about the self-expandingmember407 in a hoop-like configuration. The proximal self-expandingmember407 exerts outward radial pressure on the releasablysecured belt456. The primaryproximal release wire443 is axially moveable within theend loops468 of the proximalprimary belt456 to allow for release of the belt by proximal retraction of the primaryproximal release wire443 in the same manner as described above with respect to other embodiments of the present invention.
• Likewise, a[0182]distal portion471 of the distalprimary release wire442 is disposed withinend loops472 of the second distalprimary belt462 that radially constrains the second distal self-expandingmember411. The second distalprimary belt462 is formed in a hoop configuration about the second distal self-expandingmember411 and the second distal self-expandingmember411 exerts outward radial force on the second distalprimary belt462. The distalprimary release wire442 is axially moveable within theend loops472 of the second distalprimary belt462 to allow for release of the radial constraint as discussed above with respect to the proximalprimary release wire443 and as discussed above for other embodiments of the present invention. Thedistal portion471 of the distalprimary release wire442 is also disposed withinend loops473 of the first distalprimary belt458 and radially constrains the first distal self-expandingmember422 in a similar fashion.
• Although the distal[0183]primary release wire442 and proximalprimary release wire443 are shown as two separate components, therelease wires442 and443 could be combined into a single release member, such as the branchedrelease wire150 shown in FIG. 7I above. A branched release wire is capable of releasing multiple belts in a desired sequence by proper configuration of the lengths of the various branches of the wire. The relative amount of the release wire extending beyond the looped ends of the belt as indicated byreference numeral156 in FIG. 7I controls the timing of the release of the belts. Alternatively, a single release wire may engage both distal and proximalprimary belts456,458 and462. As thissingle release wire150 is moved proximally, the first distalprimary belt458 is first released, followed by the release of the second distalprimary belt462 and then release of the proximalprimary belt456.
• A[0184]distal portion474 of a secondary release member in the form of asecondary release wire475 is disposed withinend loops476 of asecondary belt464 that radially constrains the proximal self-expandingmember408 of thecontralateral leg405. The proximal self-expandingmember408 of thecontralateral leg405 exerts outward radial force on thesecondary belt464 when the self-expandingmember408 is in a constrained configuration. Thesecondary release wire475 is axially moveable within theend loops476 of thesecondary belt464.
• A[0185]proximal end477 of thesecondary release wire475 is secured to anactuator hub478. Arelease strand481 is secured to theactuator hub478 and is attached to the secondarybelt support member454, and is shown by way of example in the embodiment of FIG. 26 as being looped through ahole482 in theproximal end483 of the secondarybelt support member454. Both portions of therelease strand481 that are looped through theproximal end483 of the secondarybelt support member454 pass into an inner lumen484 of arelease strand tube485 as seen in FIG. 27. Therelease strand tube485 passes through an aperture486 in thedistal end435 of the outertubular member431.Release strand481 may comprise any filamentary thread or wire, metallic, polymeric, or otherwise, suitable for manipulation as will be herein described. It also may be braided or twisted if desired. Therelease strand481 may be made of a filamentary thread of ePTFE.
• As discussed above with respect to other embodiments, the[0186]release wires442,443 and475 are generally made from a biocompatible high strength alloy such as stainless steel, but can also be made from any other suitable materials. Examples include other metallic alloys such as nickel titanium, non-metallic fibers such as carbon, polymeric materials, composites thereof, and the like. As discussed above, the diameter and stiffness of therelease wires442,443 and475 can be important with respect to the diameter and stiffness of thebelts456,458,462 and464.
• The configuration of the[0187]end loops468,472,473 and476 of thebelts456,458,462 and464 may vary to suit the particular embodiment of thedelivery system400 and device to be delivered. For example, FIGS.7C-7H illustrate a variety of belt and end loop configurations that may be suitable for delivery systems for bifurcated devices. Referring to FIG. 7C,belts112 and114 are shown having a twisted configuration that has a tendency to reduce snagging or entanglement of thebelts112 and114 after deployment and release of the belts from a constrained configuration. In addition, FIG. 7C illustrates an angle α thatbelts112 and114 make with respect toline125. In one embodiment,belts112 and114 would be substantially parallel to each other when in an unconstrained state such that this angle is approximately ninety degrees. It may also be desirable to use belts that have end loops that have different cross sectional areas (or transverse dimensions). For example, FIG. 7E showsend loops81′ and81″ constrained byrelease wire24. We have found that, depending on the transverse dimension and material ofloop81′ disposed withinloop81″, elastic deformation ofloop81′ can hinder the release process whenrelease wire24 is proximally retracted. Therefore, it may be desirable to makeloop81′ from a material that is substantially smaller in cross sectional area or transverse dimension that that ofloop81″. In a particular example,loop81′ is made from nickel titanium wire having a diameter of about 0.003 to about 0.005 inch, andloop81″ is made from the same material having a diameter ranging from about 0.005 to about 0.007 inch.
• [0188]Inflation port421 extends proximally from theproximal end416 of theipsilateral leg404 of thegraft401. Theinflation port421 is coupled to adistal end487 of theinflation tube444 by a retention mechanism, such as aretention wire488, the operation of which can be the same or similar to like embodiments ofretention wire285 discussed above.
• Typically, the[0189]retention wire488 extends from theinflation port421 proximally to theproximal adapter427 ofdelivery system400. Thedistal end487 of theinflation tube444 can be disengaged from theinflation port421 by pulling on aproximal end491 ofretention wire488, as shown in FIGS. 23, 26 and31. Theretention wire488 may be a small diameter wire made from a material such as a polymer, stainless steel, nickel titanium, other alloy or metal, or composite; in a particular embodiment of the invention,retention wire488 may be a spring formed of a variety of suitable spring materials. Alternatively, theretention wire488 may have a braided or stranded configuration.
• FIG. 31 illustrates[0190]proximal adapter427 which is suitable for use with embodiments of the present invention. Theproximal adapter427 houses the proximal termination of theprimary release wires442 and443,guidewire tube436,retention wire488 andrelease wire tube441. Theproximal adapter427 has afirst side arm492 with aninner lumen493 that secures theproximal end494 of therelease wire tube441 andsecond side arm499 having an inner lumen in fluid communication withinflation material lumen506 that housesproximal end491 ofretention wire488. Theproximal adapter427 has a distal primary release wire handle495 and a proximal primary release wire handle496 that are disposed in a nested configuration on thefirst side arm492. Aproximal end497 of the proximalprimary release wire443 is secured to the proximal primary release-wire handle496. Aproximal end498 of the distalprimary release wire442 is secured to the distal primaryrelease wire handle495. This configuration prevents the operator from inadvertently deploying or activating the proximalprimary release wire443 prior to deployment or activation of the distalprimary release wire442 which could result in anundesirable graft401 deployment sequence.
• A[0191]proximal end501 of theguidewire tube436 is secured within acentral arm502 of theproximal adapter427 that has a pottedsection503. Aseal504 may be disposed on aproximal end505 of thecentral arm502 for sealing around the guidewire lumen and preventing a backflow of fluid. Thepotted section503 of thecentral arm502 prevents any injected fluids from passing into theinflation material lumen506 within theproximal adapter427 or the innertubular member430. The other functions and features of theproximal adapter427 may be the same or similar to those of theproximal adapters42 and323 shown in FIG. 1 and FIG. 17 and discussed above.
• FIG. 32 illustrates a belt[0192]support member assembly507 of thedelivery system400. Thedistal end508 of the secondarybelt support member454 is slidingly disposed within the secondary beltsupport member housing453 that is secured to the primarybelt support member452. The second distalprimary belt462 is secured to the primary belt support member452 (which in this embodiment is the guidewire tube436) and extends radially therefrom through an optional second distalprimary standoff tube511. Similar optional first distalprimary standoff tube512, proximalprimary standoff tube513 and optional secondary standoff tube514 are disposed on the first distalprimary belt458, proximalprimary belt456 andsecondary belt464, respectively.
• In general, the various features and components (including, e.g., details of various embodiments of the release wires, the self-expanding members, belts, inflation port and tube, guidewire tube, standoff tubes, proximal adapter and its associated components, the materials and dimensions for each of the various components, etc.) as discussed herein with respect to those embodiments of FIGS.[0193]1-18 may be used in the bifurcated embodiments of the present invention as discussed herein and as illustrated in FIGS.19-32.
• In use, the[0194]delivery system400 for delivery of a bifurcated intracorporeal device, specifically, abifurcated graft401, can be operated in a similar fashion to the delivery systems discussed above. FIG. 33 illustrates generally the anatomy of a patient's heart515,aorta516 andiliac arteries517. The aorta extends from the heart515 and descends into the abdomen of the patient's body. Ananeurysm518 is disposed in theaorta516 just below therenal arteries519. Theaorta516 branches into the right and leftiliac arteries517 below the aneurysm, which then become thefemoral arteries520.
• One delivery procedure of the present invention begins with delivery of a[0195]first guidewire530 into anaccess hole531 in a femoral artery, the right femoral artery532 for the procedure depicted in FIG. 34, and advanced distally through theiliac artery517 and into the patient'saorta516. Access into the femoral artery532 is generally accomplished with a standard sheath and trocar kit, although sheathless access may also be employed. It should be noted that although the procedure described herein and illustrated in FIGS.34-52 is initiated in the right femoral artery532, the same procedure could be carried out beginning in the leftfemoral artery533 with the orientation reversed. A vasodilator may optionally be administered to the patient at this point as previously discussed. If desired, a vasodilator may also be administered later in the procedure, but preferably prior to or simultaneous with the step of introducing inflation material into thegraft401.
• With the[0196]first guidewire530 positioned across theaneurysm518, asecond guidewire534 is then introduced into the ipsilateral or right femoral artery532 and guided into theiliacs517 and then back down into the contralateral or leftfemoral artery533 as shown in FIG. 35. Adistal end535 of thesecond guidewire534 may then be captured with asnare536 or similar device inserted through anaccess hole537 in the leftfemoral artery533. Thedistal end535 of thesecond guidewire534 may then be pulled out of the leftfemoral artery533 through the same left femoralartery access hole537, providing a continuous length of wire passing through eachiliac artery517 via the left and right femoral artery access holes537 and531 as shown in FIG. 35.
• Once the[0197]second guidewire534 exits theaccess hole537 in the leftfemoral artery533, atubular catheter538 may be advanced over thesecond guidewire534 through the left femoralartery access hole537 so as to extend out of the body from theaccess hole531 in the right femoral artery532 as shown in FIG. 36. This provides a continuous conduit between the right and leftiliac arteries517. With adistal end541 of thetubular catheter538 extending from theaccess hole531 in the right femoral artery532, adistal end542 of thesecondary release cable438 may then be affixed to aproximal end543 of thesecond guidewire534 as shown in FIG. 37. For purposes of simplicity, thesecondary release cable438 is shown in, e.g., FIGS.37-40 in schematic form as a single strand. However, it is understood that the term “secondary release cable” encompasses a single or multiple-component feature of the present invention that may be used to assist in the deployment of the graft. For instance, in the embodiment depicted herein, thesecondary release cable438 represents the combination of therelease strand481 andrelease strand tube441 discussed above in conjunction with, e.g., FIG. 26. Other variations of this combination are within the scope of the present invention.
• The[0198]second guidewire534 is then pulled out of thetubular catheter538 from the left femoralartery access hole537, in the direction indicated by thearrow544 in FIG. 37, so that thesecondary release cable438 then extends through thetubular catheter538 from the right iliac artery to the left iliac artery. Thetubular catheter538 may then be withdrawn, leaving thesecondary release cable438 extending through the left and rightiliac arteries517 from theaccess hole531 in the right femoral artery532 to theaccess hole537 in the leftfemoral artery533 as shown in FIG. 38. Thefirst guidewire530 remains in position across theaneurysm518.
• The[0199]delivery system400 is then advanced into the patient's right femoral artery532 through theaccess hole531 over thefirst guidewire530 as shown in FIG. 39. It may be desirable to apply tension to thesecondary release cable438 as thedelivery system400 is advanced to the vicinity of theaneurysm518 so as to remove slack in thecable438 and prevent tangling of thecable438 or the like. Tension on thesecondary release cable438 may also help to prevent twisting of thedelivery system400 during insertion.
• FIGS.[0200]37A-B show an optional marker band that may disposedadjacent nosepiece434 or generally in the vicinity of the distal end of thedelivery system425. Such amarker band551 may also be integral with thedelivery system400; for example, it may be incorporated as part of thedistal nosepiece434. Auseful marker551 can be one that does not add to the profile of thedelivery system400 as shown in FIG. 37A (i.e., one that does not give the delivery system400 a higher diameter). The embodiments of FIGS.37A-B are useful in the present embodiment, although they may be used in the embodiments discussed above. Such a marker may be used to aid the operator in introducing thedelivery system400 without twisting.
• For example, the[0201]marker embodiment551 of FIG. 37A comprises a marker body552 in the form of a simple discontinuous ring made of an appropriate radiopaque material (e.g., platinum, gold, etc.) visible under fluoroscopy, etc. The cross section of the ring may be asymmetric so that under fluoroscopy the cross section may be seen in the vicinity of thediscontinuity553. The operator will be able to tell if thedelivery system400 is twisted by how the ring552 is presented under fluoroscopy. Alternatively, ring552 may be continuous but have a notch or similar cutout to serve the same purpose.
• The[0202]embodiment554 of FIG. 37B is an example of such a marker. Here, both anotch555 and two circular holes556 have been cut out of themarker body557 for easier determination of its orientation when disposed on the notch or other part of thedelivery system400. For instance, in an orientation where the two circular holes556 are aligned with respect to the fluoroscope field of view, the user will see a single circular hole to the left of a triangular or vee-shape cutout555 on the side of themarker554. As the angular orientation of the device400 (and thus the marker554) about the longitudinal axis changes, the appearance of the two circular holes556 andside notch555 will change. If the device is twisted clockwise ninety degrees from this orientation along its centrallongitudinal axis554A, for instance, the circles556 will largely disappear from view and theside notch555 will generally appear in the front of the field of view as a symmetric diamond. Comparing these views will allow the user to know that theentire delivery system400 has twisted about ninety degrees. Keeping the same orientation, then, will be made easier with such amarker554.
• For each of the embodiments of FIGS.[0203]37A-B, variations in the shape, number, orientation, pattern and location of thenotch553 and555, holes556 or other discontinuity, as well as various marker body dimensions cross sectional shape, etc., may be realized, as long as themarker551 and554 is configured so that the angular orientation of thedelivery system400 may readily be determined by the user under fluoroscopy or similar imaging technique.
• The[0204]delivery system400 is positioned in a location suitable for initiating the deployment process, such as one in which thedistal end425 of thedelivery system400 is disposed beyond, or distal to the position in which thegraft401 will be placed, as shown in FIG. 40. This position allows theproximal end483 of the secondarybelt support member454 to be laterally displaced without mechanical interference from the patient's vasculature. Such clearance for lateral displacement is shown in FIG. 44.
• Once the[0205]distal section426 of theelongate shaft423 and theendovascular graft401 are positioned, the deployment process is initiated. First, the outertubular member431 is proximally retracted by pulling on the proximal end433 of the outertubular member431 relative to the innertubular member430. The innertubular member430 should be maintained in a stable axial position, as the position of the innertubular member430 determines the position of the constrainedbifurcated graft401 prior to deployment. Upon retraction of the outertubular member431, the constrainedbifurcated graft401 is exposed and additional slack is created in thesecondary release cable438 as shown in more detail in FIG. 41.
• Alternatively, a variety of different components may be substituted for the outer[0206]tubular member431 in some of the embodiments of the invention. For instance, a shroud, corset, mummy-wrap, or other cover may be released or actuated to expose theconstrained graft401 after the deliveringsystem400 is introduced into the vasculature.
• The slack in the[0207]secondary release cable438 is taken up by applying tension to bothlengths561 and562 of therelease strand481 as shown by thearrows563 in FIG. 41. In alternative embodiments, release strand is not continuous such thatlengths561 and562 each has a free end, each of which may be manipulated by the operator. As tension continues to be applied to bothlengths561 and562 of therelease strand481, the secondarybelt support member454 begins to slide within the secondary beltsupport member housing453 in a proximal direction as shown by thearrow564 in FIG. 42. The secondarybelt support member454 continues to slide proximally until all the slack is removed from an axially compressed or foldedportion565 of thecontralateral leg405 of thegraft401 shown in FIG. 41 and the primary and secondarybelt support members452 and454 are oriented relative to the secondary beltsupport member housing453 as generally shown in FIG. 43. Rotational movement of the secondarybelt support member454 relative to the secondary beltsupport member housing453 is prevented by the non-circular or asymmetric cross section of themember454 as shown in FIGS.28-28B. This prevents thecontralateral leg405 from twisting or becoming entangled with other components of thegraft401 ordelivery system400 during deployment.
• Axial compression of all or a portion of the[0208]contralateral leg405 while thegraft401 is in a constrained state within thedelivery system400 prior to deployment allows the axial position of the two proximal self-expandingmembers407 and408 to be axially offset from each other. Alternatively, graftlegs404 and405 having different lengths may be used to prevent overlap of the self-expandingmembers407 and408 within thedelivery system400. The cross sectional profile or area of the overlap self-expandingmembers407 and408 is generally greater than that of the adjacent polymer material portion of thelegs404 and405 of thegraft401, so eliminating the overlap can be desirable. Theself20 expanding members407 and408 are typically made of a metal or metallic alloy and maintain a cylindrical configuration, even when in a constrained state. The polymer material of thelegs404 and405 ormain body portion402 of thegraft401, by contrast, is relatively soft and malleable and can conform to the shape of whatever lumen in which it may be constrained. Placing both proximal self-expandingmembers407 and408 adjacent each other in a compressed state at a single axial position within thedelivery system400 would require a configuration in which two objects having an approximately circular cross section are being placed within another circular lumen. Such a configuration generates a significant amount of wasted or unused cross sectional area within that axial position of thedelivery system400 and would likely result in less flexibility and greater cross section than adelivery system400 in which the proximal self-expandingmembers407 and408 are axially offset.
• A[0209]gap566 indicated by the arrows567 in FIG. 44 allows theproximal end483 of the secondarybelt support member454 and secondary releasewire actuator hub478 to move in a lateral direction without mechanical interference from thecarina568 of theiliac artery bifurcation569.Gap566 may vary depending on the patient's particular anatomy and the specific circumstances of the procedure.
• The lateral movement of the[0210]contralateral leg405 and secondarybelt support member454 is accomplished by application of tension on bothlengths561 and562 of therelease strand481 as shown by thearrows571 in FIG. 44. This movement away from the primarybelt support member452 allows the secondarybelt support member454 to transition from alignment with the rightiliac artery572 to alignment with the leftiliac artery573 as shown in FIG. 44.
• Once the[0211]ipsilateral leg404 of thegraft401 andcontralateral leg405 of thegraft401 are aligned with the right and leftiliac arteries572 and573, respectively, thedelivery system400 may then be retracted proximally, as shown by thearrow574 in FIG. 45, so as to reposition thedistal section426 of theelongate shaft423 and thebifurcated graft401 into the desired position for deployment as shown in FIG. 45.
• As discussed above with respect to placement of a[0212]tubular graft11 embodiment of the present invention, when deploying thegraft401 in theabdominal aorta516 it is generally desirable to ensure that thedistal end403 of the graftmain body portion402 is installed proximal to, or below, therenal arteries519 in order to prevent their significant occlusion. However, the distal self-expandingmembers411 and422 of thegraft401 may, depending upon the anatomy of the patient and the location of theaneurysm518, partially or completely span theostia575 of one or bothrenal arteries519. It can be desirable, however, to ensure thatostia575 of therenal arteries519 are not blocked by thedistal end403 of the graftmain body portion402. As discussed previously, a variety ofimaging markers551 and554 may be used on either or both thedelivery system400 and thegraft401 itself to help guide the operator during the graft positioning process.
• After proper positioning, the first and second distal self-expanding[0213]members411 and422 may then be deployed. The operator first unscrews or otherwise detaches a threadedportion576 of the distal primary release wire handle495 from an outer threadedportion577 of a first sidearm end cap578 shown in FIG. 31. Next, the distal primary release wire handle495 is proximally retracted, which in turn retracts the distalprimary release wire442 in a proximal direction, as shown by the arrow581 in FIG. 46. As thedistal end582 of the distalprimary release wire442 passes through theend loops472 and473 of the first distalprimary belt458 and second distalprimary belt462, theend loops472 and473 are released, freeing the first distal self-expandingmember422 and second distal self-expandingmember411 to self-expand in an outward radial direction so to contact aninner surface583 of the patient'saorta516. The first and second distalprimary belts458 and462 remain secured to the primarybelt support member452 and will eventually be retracted from the patient with thedelivery system400 after deployment is complete.
• As the first and second distal self-expanding[0214]members411 and422 expand and contact theaorta516, adistal end403 of the graftmain body portion402 opens with the self-expandingmembers411 and422 and promotes opening of the graft polymer material portion from the flow of blood into thedistal end403 of the graftmain body portion402 with a “windsock” effect. As a result, once the first and second distal self-expandingmembers411 and422 are expanded to contact the aortainner surface583, the graftmain body portion402 andlegs404 and405 balloon out or expand while the proximal ends416 and417 of thelegs404 and405 of thegraft401 remain constricted due to the constrained configuration of the proximal self-expandingmembers407 and408 of the ipsilateral andcontralateral legs404 and405, as shown in FIG. 46. At this point, there typically will be partial or restricted blood flow through and around thegraft401.
• [0215]Bifurcated graft401 may then be optionally be inflated with an inflation material viainflation tube444 andinflation port421 until theinflatable channels418 andinflatable cuffs413,414 and415 have been filled to a sufficient level to meet sealing and other structural requirements necessary for the bifurcated graftmain body portion402 and the ipsilateral andcontralateral legs404 and405 to meet clinical performance criteria. As described in later conjunction with an alternative embodiment of the present invention, inflating thegraft401 prior to deploying the proximal and distal self-expandingmembers407 and408, respectively, is useful in anatomies where the vasculature is tortuous or angled.
• Next, the proximal self-expanding[0216]member407 of theipsilateral leg404 is deployed. Deployment of the first and second distal self-expandingmember411 and422 has exposed the proximal primaryrelease wire handle496, making it accessible to the operator. A threaded portion584 of the proximal primary release wire handle496 is unscrewed or otherwise detached from an inner threaded portion585 of the first sidearm end cap578. The proximal primary release wire handle496 may then be retracted proximally so as to deploy the proximalprimary belt456 and proximal self-expandingmember407 of theipsilateral leg404 as shown in FIG. 47.
• FIG. 48 depicts an enlarged view of the[0217]proximal end483 of the secondarybelt support member454. The proximal self-expandingmember408 of thecontralateral leg405 is secured to theproximal end417 of thecontralateral leg405. The proximal self-expandingmember408 is constrained in a radial direction by thesecondary belt464, which hasend loops476 releasably constrained by thedistal end587 of thesecondary release wire475. Theproximal end477 of thesecondary release wire475 terminates with and is secured to theactuator hub478. The release strand is secured to theactuator hub478 and loops through an aperture orhole482 in theproximal end483 of the secondarybelt support member454. As discussed above, a portion of therelease strand481 is disposed within therelease strand tube485 to form thesecondary release cable438.
• When both a[0218]first length561 andsecond length562 of therelease strand481 are pulled together in a proximal direction from a proximal end588 of thesecondary release cable438, the entire pulling force is exerted on theproximal end483 of the secondarybelt support member454 because the loopeddistal end542 of therelease strand481 pulls on theproximal end483 of the secondarybelt support member454 without displacing theactuator hub478.
• When deployment of the proximal self-expanding[0219]member408 of thecontralateral leg405 is desired, the operator applies tension in a proximal direction only to thefirst length561 of therelease strand481, which extends proximally from theactuator hub478. The direction of such tension is indicated in FIG. 48 by thearrows591. Upon the application of this proximal tension, theactuator hub478 is moved proximally, as is thesecondary release wire475 that is secured to theactuator hub478. The proximal self-expandingmember408 of thecontralateral leg405 deploys when thedistal end587 of thesecondary release wire475 passes through theend loops468 of thesecondary belt464 so as to release the radial constraint on the proximal self-expandingmember408 imposed by thesecondary belt464. Upon release of the radial constraint, the proximal self-expandingmember408 expands so as to contact aninside surface592 of the leftiliac artery573 as shown in FIG. 49. Once the proximal self-expandingmember408 of thecontralateral leg405 is expanded, the operator may then apply tension to bothlengths561 and562 of therelease strand481 to withdraw the secondarybelt support member454 from the housing453 (as shown in FIG. 50) and remove it from the patient's vasculature through the left femoralartery access hole537.
• FIG. 51 depicts an alternative embodiment of a belt[0220]support member assembly600 in which the secondary belt support member601 is detached from the primarybelt support member602 by withdrawal of alatch wire603. Generally, all other features of thedelivery system604 of the embodiment of FIG. 51 can be the same as the delivery systems discussed above. It should be noted, however, that the embodiment shown in FIG. 51 does not allow the secondary belt support member601 to slide in an axial direction relative to the primarybelt support member602. As such, it may be desirable to use this embodiment to deliver and deploy a graft having legs that are not substantially equal in length. Otherwise, if proximal self-expanding members are to be axially offset, the secondary belt support member601 would have to be detached from the primarybelt support member602 prior to deploying and releasing the secondary belt (not shown).
• In another configuration (not shown), a similar retention or[0221]latch wire603 passes through aligned aperatures in the secondarybelt support member454 and a housing, such as secondary beltsupport member housing453 of FIG. 43. Linear and rotational motion of secondarybelt support member454 relative to primarybelt support member452 is prevented untilwire603 is withdrawn, freeingmember454 to be removed fromhousing453. Typically the aperatures are disposed at an angle (such as about45 degrees) relative to the surface of the members through which they reside so to minimize the angles through whichretention wire603 turn as is passes through the apertures. Retention wire may double as the primary proximal release wire for one or both of proximal self-expandingmembers411 and422.
• FIG. 52 shows an alternative belt support member assembly[0222]606 wherein the secondarybelt support member607 is laterally displaced and locked into a position parallel with the primary belt support member608 prior to removal of thedelivery system609 from the patient's vasculature. All other features of thedelivery system609 of the embodiment of FIG. 52 can be the same as the delivery systems discussed above. In use, after all self-expanding members have been deployed, thedelivery system609 is advanced distally into the patient's vasculature, as shown by thearrow610 in FIG. 52, in order to achieve a gap between a proximal end611 of the secondarybelt support member607 and the patient's vasculature as shown by the arrows612 in FIG. 52. A constrainingring613 is then retracted proximally, as indicated by thearrow614, so as to force the secondarybelt support member607 to be laterally displaced as shown by the arrow615, also in FIG. 52. Once the secondarybelt support member607 has been fully retracted in a lateral direction so as to be substantially parallel to the primary belt support member608, thedelivery system609 can then be retracted from the patient's vasculature.
• If not previously filled, the[0223]bifurcated graft401 may thereafter be inflated with an inflation material described with respect to thetubular graft embodiment11.
• For all the embodiments described, both tubular and bifurcated, inflation is generally accomplished by inserting or injecting, via one or more device such as a syringe or other suitable mechanism, the inflation material under a pressure- or volume-control environment.[0224]
• For instance, in one embodiment of a pressure-control technique, a volume of inflation material is first injected into the delivery system[0225]400 (which at this point may include the graft, but may also include the inflation tube444). The particular desired volume of inflation material will depend on several factors, including, e.g., the composition and nature of the inflation and polymer graft material, the size of thegraft401 to be deployed, the vessel or lumen diameter into which thegraft401 is deployed, the configuration of the graft401 (tubular, bifurcated, etc.), the features of the graftmain body402 and (if present)legs404 and405, and the conditions during the procedure (such as temperature).
• Thereafter, the operator may affix a pressure control device, such as an inflation syringe, to the injection port[0226]621 of theproximal adapter427 of the inflation tube and apply a pressure to thedelivery system400 and agraft401 for a period of time. This serves to ensure that the fill material previously introduced enters thegraft401 and fills it to the desired pressure level.
• We have found that a useful pressure-control approach involves a series of such constant pressure applications, each for a period of time. For instance, the[0227]graft401 may first be pressurized at a level from about 5 psi to about 12 psi or higher, preferably about 9 psi, for between about 5 seconds and 5 minutes, preferably about 3 minutes or more. Optional monitoring of the fluid and the device during the fill procedure may be used to help ensure a proper fill. Such monitoring may be accomplished under fluoroscopy or other technique, for instance, if the fill material is radiopaque.
• Thereafter, the fill protocol may be completed, or the pressure may be increased to between about 10 psi and about 15 psi or higher, preferably about 12 psi, for an additional period of time ranging from between about 5 seconds and 5 minutes or more, preferably about 1 minute. If the[0228]graft401 so requires, the pressure may be increased one or more additional times in the same fashion to effect the proper fill. For instance, subsequent pressure may be applied between about 12 and 20 psi or more, preferably about 16 psi to 18 psi, for the time required to satisfy the operator that thegraft401 is sufficiently filled.
• The details of particular pressure-time profiles, as well as whether a single pressure-time application or a series of such applications is used to fill embodiments of the[0229]graft401 will depend on the factors described above with respect to the volume of fill material used; the properties and composition of the fill material tend to be of significance in optimizing the fill protocol. For example, a stepped series of pressure-time profiles as described above is useful when the fill material comprises a hardenable or curable material whose physical properties may be time-dependent and which change after being introduced into thegraft401 and itsdelivery system400.
• Alternatively, a volume-control method may be utilized to fill embodiments of the[0230]grafts11 and401, including both tubular and bifurcated. Here, a volume of fill material is again introduced into thedelivery system400 as described above. In this method, however, the volume of fill material used is precisely enough material to fill thegraft401, theinflation tube444, and any other component in thedelivery system400 through which the fill fluid may travel on its way to thegraft401. The operator introduces the predetermined quantity of fill material, preferably with a syringe or similar mechanism, into theinflation tube444 andgraft401. A precise amount of fill material may be measured into a syringe, for example, so that when the syringe is emptied into thedelivery system400 andgraft401, the exact desired amount of fill material has reached thegraft401. After a period of time (which period will depend on the factors previously discussed), the syringe or equivalent may be removed from theinflation tube444 or injection port621 ofproximal adapter427 and the procedure completed.
• A pressurized cartridge of gas or other fluid may be used in lieu of a syringe to introduce the fill material into the delivery system and graft under this volume-control regime so to provide a consistent and reliable force for moving the fill material into the[0231]graft401. This minimizes the chance that variations in the force and rate of fill material introduction via a syringe-based technique affect the fill protocol and possibly the clinical efficacy of thegraft401 itself.
• For each of the pressure- and volume-control configurations, an optional pressure relief system may be included so to bleed any air or other fluid existing in the[0232]delivery system400 prior to the introduction of the fill material (such as theinflation tube444 or graft401) so to avoid introducing such fluid into the patient. Such an optional system may, for example, comprise a pressure relief valve at thegraft401/inflation tube444 interface and a pressure relief tube disposed through the delivery system400 (e.g., adjacent the inflation tube444) terminating at theproximal adapter427 and vented to the atmosphere.
• When[0233]graft401 is deployed in certain anatomies, such as those where the iliac arteries are tortuous or otherwise angled, the lumen of one or more of graftinflatable cuffs413,414 and415 andchannels418 of may become pinched or restricted in those portions of thegraft401 experiencing a moderate or high-angle bend due to the tortuosity of the vessel into which that portion ofgraft401 is deployed. This reduction or even elimination of cuff/channel patency can hinder and sometimes prevent adequate cuff and channel inflation.
• In addition,[0234]graft401main body402 and/orlegs404,405 may, upon initial retraction of outertubular member431 and deployment into the vasculature, resist the “windsock” effect that tends to open up the graft to its nominal diameter. Then in turn may lead toinadequate cuff413,414, and415 andchannel418 patency prior to their injection with inflation material. The windsock effect has a higher likelihood of being hindered whengraft401 is deployed in relatively tortuous or angled anatomies; however, it may also be made more difficult when graft401 (and even tubular graft embodiments such as graft11) is deployed in relatively non-tortuous anatomies.
• To address this issue, we have found it useful to incorporate an optional ripcord or monofilament into the[0235]inflatable channel418. Pre-loading such aripcord510 into all or a portion of thechannel418 that runs along graftipsilateral leg404 andmain body portion402 promotes effective inflation of the graft cuffs and channels as will be described below in detail.
• [0236]Ripcord510 extends in one embodiment fromdistal cuff413 throughchannel418,proximal cuff414 andinflation port421, and continues throughinflation tube444 and throughsecond side arm499 ofproximal adapter427 as shown in FIG. 31A. Aflexible fill catheter523 may be affixed to end ofsecond side arm499 atinjection port509.
• [0237]Ripcord510 extends throughinjection port509 andcatheter523 where it is affixed to a removable Luer-type fitting or cap521 atcatheter523 terminus525 (which can serve as an injection port). Alternatively, in lieu ofcatheter523, fitting521 may be removably connected directly toinjection port509. Fill catheter may compromise an optional pressure relief valve (not shown).
• In use, after[0238]graft401 has been deployed into the vasculature but prior to injecting the inflation material throughsecond side arm499, the operator removes fitting521 fromcatheter523 and pullsripcord510 proximally out of theipsilateral graft channel418,second side arm499 and out through the end ofcatheter523. This leaves behind an unobstructed lumen inchannel418 through which inflation material may pass as it is injected into the device, despite any folds, wrinkles, or angles that may exist ingraft401 due to vessel tortuosity or angulation, lack of windsocking, or other phenomena. Inflation material may then be injected intochannel418 andcuffs413,414 and415 throughsecond side arm499 as described elsewhere herein. Inflation material passes through the lumen inchannel418 left behind afterripcord510 is removed and reachesdistal cuff413. Ascuff413 fills, a hemostatic seal is created at distal end ofgraft401 which promotes the desired windsocking of the graft. This in turn promotes the effective filling of the rest of thecuffs414,415 andchannels418 and any other lumens in which the inflation material may be directed.
• Suitable materials for[0239]ripcord510 include polymeric monofilaments, such as PTFE, Polypropylene, nVion, etc. Metallic filaments such as stainless steel, nickel titanium, etc. may be used as well. The diameter ofripcord510 should be small compared to the diameter ofchannel418 lumen to minimize impact on delivery system profile, yet large enough to permit reasonable flow of inflation material intochannel418 lumen following its removal. We have found that aripcord510 diameter of between about 0.005 inch and 0.025 inch to be appropriate; in particular, a ripcord diameter of about 0.015 inch is suitable.
• Alternatively, or in conjunction with[0240]ripcord510, one or more permanent monofilament lumen patency members or beads may be incorporated into one or more of the cuffs and channels to facilitate the inflation process. We have found it useful to incorporate a single bead into graftcontralateral leg405channel418 along withripcord510 in the graftipsilateral leg404channel418.
• FIG. 31B is a simplified cross sectional schematic view of[0241]contralateral leg405inflatable channel418 having abead520 disposed in alumen522 ofchannel418, taken alongline31B-31B in FIG. 19. Typically bead520 extends fromproximal cuff414 todistal cuff413, although it may be disposed in only a portion ofchannel418 or in other cuffs or channels ofgraft401.
• [0242]Channel418 is shown in FIG. 31B as bent or angled out of the plane of the page to simulatecontralateral limb405 placement in a highly angled iliac artery. Under such bending forces, thewalls524 ofchannel418 tend to close onlumen patency member520, reducing the size oflumen522 to be confined to the areas indicated in FIG. 31B. As can be seen, bead520 prevents thelumen522 from collapsing to the point wherelumen522 loses patency sufficient for satisfactory passage of inflation material.
• [0243]Bead520 may have the same dimensions and comprise materials the same as or similar toripcord510. In particular, we have found a PTFE bead having a diameter of about 0.020 inch to be useful in thechannel418 embodiments of the present invention.
• We have found that incorporating a[0244]ripcord510 and/or one or morelumen patency members520 in the system of the present invention enhances the likelihood that graft cuffs and channels will reliably and sufficiently fill with inflation material. In one extreme experiment designed to test the feasibility of this concept, a bifurcated graftcontralateral leg405 having abead520 disposed in thecontralateral limb channel418 was tied into a knot at the legproximal end417. Inflation material was injected through ipsilateralleg inflation port421 under a pressure-control protocol. All cuffs and channels ofgraft401, includingcontralateral leg channel418 andproximal cuff415, filled completely without having to increase the fill pressure beyond normal levels.
• Although the benefits of[0245]ripcord510 and one or more beads520 (together or in combination) may be most readily gained whengraft401 is deployed in tortuous or highly angled anatomies, these components are also useful in grafts deployed in relatively straight and non-tortuous anatomies. They may also be used in tubular stent-grafts of the present invention.
• Turning now to FIG. 53, an embodiment of a bifurcated[0246]graft delivery system625 and method is illustrated. This embodiment is tailored to provide for a controlled withdrawal of a secondary release cable from a lumen of an innertubular member628 so to help eliminate the possibility that the release cable626 becomes entangled or otherwise twisted during deployment.
• Shown in FIG. 53 is a well[0247]633 is disposed in the innertubular member628. Well633 contains arelease strand629 that is looped at itsproximal end634 outside the well633 through anaperture635 in the secondarybelt support member636 and that is affixed or attached at itsdistal end637 to asecond guidewire638. Thesecond guidewire638 is shown in the embodiment of FIG. 53 as disposed in its ownoptional lumen639 within the innertubular member628.
• Within the well[0248]633, therelease strand629 is arranged to form a “u-turn” in which it changes direction to double back on itself atjuncture641 as shown in FIG. 53. Atjuncture641, afriction line642 is looped around all or a portion of therelease strand629. Thisfriction line642 is fixed to the bottom of the well633 on oneend642A and is free on another end642B. Thefriction line642 is preferably a polymeric monofilament such as polyimide, etc., but may be metallic and may be braided as necessary to achieve the desired friction characteristic needed to interact withrelease strand629.Friction line642 has a length sufficient to interact with therelease strand629 during the deployment process until therelease strand629 has been completely removed from the well633 as will now be described in detail.
• In use, the configuration of FIG. 53 works as follows. Once the left and right femoral access holes[0249]531 and537, discussed above, have been created, thedelivery system625 is introduced into and through the patient's vasculature. Asnare catheter643 is introduced into the left femoral artery access hole, such as the left femoralartery access hole537 discussed above. The operator then captures thetip644 of thesecond guidewire638 with thesnare643. In the embodiment of FIG. 53, thesecond guidewire638 is shown as pre-attached to therelease strand629 at thedistal end637.
• A[0250]ball capture tip638A or similar member may optionally be disposed on thetip644 ofsecond guidewire638 to facilitate its capture bysnare catheter643 and prevent possible injury to the vessel intima. In addition,tip638A may be made radiopaque so that it may be readily located by the operator during the procedure. When in the form of a ball, tip638A may have a diameter ranging from between about 0.020 inch to about 0.120 inch, specifically, between about 0.040 inch to about 0.060 inch. Although not shown in the figures,second guidewire638 may also have one or more additional sections branching therefrom, each having a tip or member similar totip644, includingtip638A, so to provide the operator with one or more alternative sites for capture withsnare643 incase tip638A is inaccessible.
• An[0251]angled extension639A may optionally be provided on one or both of the top ofoptional lumen639 and/or the top ofwell633.Angled extension639A may be made of any suitable polymeric or metallic material such as stainless steel. As seen in FIGS.53-54,extension639A disposed on the top oflumen639 is generally biased towards the artery in whichsnare643 is disposed at an angle of between about 20 degrees and about 120 degrees, specifically, between about 40 degrees and about 95 degrees, so to guide therelease strand629 and653 in the proper direction and thus facilitate ease of capture bysnare643.
• As the[0252]second guidewire638 is pulled out of the innertubular member628 from the left femoralartery access hole537 in the direction shown by thearrow544 in FIG. 37, therelease strand629 feeds out of the well633 in an orderly and linear fashion in a direction from the release stranddistal end637 to itsproximal end634. This is made possible by the forces created at the “u-turn” orjuncture641 by the physical interface with thefriction line642. The friction force (which can be tailored by the proper combination ofrelease strand629 andfriction line642 diameters and their materials and by properly dimensioning of the well633, for example) provides enough resistance to counter the force applied by the operator so that the “u-turn” orjuncture641 moves in an orderly fashion in a direction from the well bottom633 to thedistal end646 of the innertubular member628 until it exits out of the outertubular member628. At this point, any remainingfriction line642 at thejuncture641 is superfluous as it has served its purpose of facilitating an orderly withdrawal of therelease strand629. The operator continues to pull on thesecond guidewire638 as previously described so that therelease strand629 extends through the left femoralartery access port537. We have found the embodiment of FIG. 53 to be useful in achieving an orderly and tangle-free deployment.
• Alternatively, any number of other arrangements in which the[0253]release strand629 may be fed out of the outertubular member628 in an orderly manner is within the scope of the present invention. For instance, the well651 shown in FIGS.54-56 is, for instance, an extruded polymeric part having a unique cross-sectional configuration that eliminates the need for thefriction line642 in the embodiment shown in FIG. 53. Here, a narrowing constraint orgap652 runs the length of the well interior651, forming a physical barrier between first and second opposingportions654 and655 of therelease strand653, shown in FIGS.54-56. The constraint orgap652 is sized to allow the passage therethrough of the release strand juncture or “u-turn”656. As the operator pulls therelease strand653 out of the well651, the constraint orgap652 prevents the opposingportions654 and655 of therelease strand653 from crossing into the other side of thewell651. Said another way, the constraint orgap652 keeps the juncture or “u-turn”656 within its vicinity to facilitate an orderly withdrawal of therelease strand653 from the well651. In this embodiment, therelease strand653 can have a diameter of between about 0.004 and 0.010 inch; specifically between about 0.006 and 0.007 inch. The gap orconstraint652 should be between about 0.003 and about 0.009 inch; preferably between about 0.005 and about 0.006 inch.
• Yet another variation of this embodiment, shown in FIG. 57, includes a[0254]post661 disposed in a well652 around which therelease strand663 is wound such that as the operator pulls the distal portion664 of therelease strand663 out of the distal end665 of the well652, therelease strand663 unwinds in an orderly fashion from thepost661. Thepost661 may be optionally configured to spin on its longitudinal axis, similar to that of a fishing reel spinner, to facilitate the exit of therelease strand663.
• Other variations, such as a block and tackle arrangement (not shown), are envisioned in which the[0255]release strand663 is looped through a grommet or similar feature. The grommet provides the necessary friction to prevent theentire release strand663 from pulling out of the well652 in one mass as soon as the operator applies a force on a distal end thereof. Any arrangement in which a frictional or similar force is utilized to allow for the orderly dispensation of therelease strand663 from the shaft or post661 is within the scope of the embodiment contemplated.
• FIG. 58 depicts an optional hinged design for the belt support members that is particularly useful for deploying the bifurcated stent-graft in tortuous and/or angled anatomies, although it may be used in all anatomies.[0256]Bifurcated graft401 is depicted in phantom for reference. Ahinge body700 is affixed to guidewire tube436 or primarybelt support member452.Aperture702 disposed on one side of primarybelt support member452 is configured to receivehinge attachment member704, which in this embodiment is a wire that is looped throughaperture702 and fixed to secondarybelt support member454. The hinge created ataperture702 allowssupport member454 to swing away from and towards primarybelt support member452 in the direction indicated by arrows708 in FIG. 58.
• As shown in FIG. 58,[0257]aperture702 is disposed on the side of primarybelt support member452 opposite that on which secondarybelt support member454 resides to facilitate extraction of the belt support members from the graft and the patient's body after graft deployment. However,aperture702 may also be disposed on the same side of primarybelt support member452 as that of secondarybelt support member454 or in any suitable orientation aroundmember452.
• [0258]Release strand710 is affixed to releasestrand attachment member706 at secondary belt support memberproximal end714 and is preferably a stainless steel wire having a diameter of between about 0.004 inch and 0.010 inch, although other materials and diameters may be used.Secondary belt716 is shown disposed onsupport member454 along withoptional silicone tubing711.
• Chiefly in tortuous or angled anatomies, but also in straighter vessels, it is useful to allow for a degree of slack in the[0259]contralateral limb405 to be loaded into theelongate shaft423. Such slack helps thecontralateral leg405 negotiate various bends in the iliac and/or femoral arteries. The total amount of slack ΔI ideally necessary for a graft limb such aslimb405 to negotiate an angle dΔΘ is represented by the equation:
• ΔI=dΔΘ
• “ΔΘ” is the cumulative angle change (the sum of the absolute value of the angles through which the limb must negotiate) along its length, measured in radians, and where “d” is the diameter of the graft limb.[0260]
• The hinge design of FIG. 58 allows the necessary amount of slack ΔI to be maintained in the[0261]contralateral leg405 both during the step of loadinggraft401 inshaft423 and during graft deployment and placement. Note that in an embodiment of the present invention, a predetermined amount of slack may also be built into theipsilateral leg404 as it is assembled for delivery. By building a predetermined amount of slack in each of the legs ofgraft401, the most prevalent patient anatomies may, for instance, be targeted so that the average graft delivery procedure will require the smallest amount of leg adjustment or manipulation by the operator.
• After[0262]graft401 has been deployed, the apparatus of FIG. 58 is next withdrawn from the graft and the patient's vasculature in the direction ofarrows712 as shown in FIG. 59 overguide wire530. During this withdrawal, secondarybelt support member454 rotates aboutaperture702 and pivots towards primarybelt support member452 in the direction ofarrow713. An optional buttress may be employed as described later to facilitate the withdrawal process.
• Both primary and secondary belt support members are ideally radiopaque to facilitate withdrawal from the vasculature. Secondary[0263]belt support member454 and hingeattachment member704 should be flexible enough to turn the corner aroundgraft bifurcation406 with little or no permanent deformation as the operator withdraws the primarybelt support member452 in the direction ofarrows712.
• Withdrawal of[0264]member452 causes secondarybelt support member454 to first retreat fromcontralateral limb405 until theproximal end714 of secondarybelt support member454 clears the graft walls in the vicinity ofbifurcation406, allowing the hinge to further act to align secondary belt support member in a generally parallel relationship with primarybelt support member452 as both are then withdrawn through theipsilateral leg404 and eventually out of the patient's body through rightfemoral access hole531.Release strand710 follows secondarybelt support member454 out of the body.
• FIGS.[0265]59A-B depict a variation of this hinge design that limits rotation of the secondarybelt support member454 to a single plane. Here,hinge body732 is fixedly disposed on adistal portion451 of primarybelt support member452 and comprises an offsetflanged pin734 or like element.Pin734 is disposed in anaperture736 that runs through thedistal end508 of secondarybelt support member454 and hingebody732. In this configuration, secondarybelt support member454 is rotatably secured to pin734 byoptional flange738 and is free to rotate aboutpin734 in the direction indicated by arrows740 to facilitate withdrawal of the delivery apparatus from the patient. The optional offset feature ofpin734 assists in the extraction of the belt support members from the graft and the Patient's body after graft deployment.
• FIG. 60 shows a close up partial cross-sectional view of the[0266]proximal end417 of graftcontralateral leg405 disposed on the FIGS.58-59 (or alternatively FIG. 59A-B) secondarybelt support member454.Release strand tube718, part ofsecondary release cable721, houses releasestrand710, a secondary release wire719 (which holdssecondary belt716 around contralateral proximal self expanding member408), and ashield line720 that is fixedly attached at itsdistal end722 to optional contralateral self-expandingmember shield724.
• Optional expanding[0267]member shield724 comprises PET or similar polymeric material.Shield724 acts as a shroud to cover proximal self-expandingmember408, protectingipsilateral leg404 from being damaged by self-expandingmember408 during delivery system assembly and graft deployment. Further,shield724 prevents direct contact between contralateral self-expandingmember408 and ipsilateral self-expandingmember407, keeping the various self expanding member components from snaring one another or otherwise getting entangled. The exact position of graft contralateral proximal self-expandingmember408 relative to graftipsilateral leg404 and self-expandingmember407 will depend on several factors, one of which is the degree of slack built into thegraft legs404,405 onmembers452 and454.
• [0268]Shield724 may be removed prior to retraction ofsecondary release wire719 by retractingshield line720 in the direction indicated byarrow729, typically afterrelease strand tube718 has been removed, and ultimately out of the patient's body through left femoralartery access hole537. Asshield724 is retracted,release strand710 andsecondary release wire719 pass throughwire apertures728 and730, respectively. Alternatively, a single wire aperture may be disposed onshield724 through which bothrelease strand710 andsecondary release wire719 pass.
• A variation in the deployment sequence that may be used with any of the sequences and equipment described above may be appropriate in certain clinical settings when the patient's vasculature exhibits a degree of tortuosity and/or angulation.[0269]
• Related to the cuff and channel lumen patency matter discussed above are at least two additional considerations when deploying a device such as[0270]bifurcated graft401 in tortuous or angled anatomies. First, it can be more challenging to maintain the patency of either or both the blood flow passageways formed by the walls of graftcontralateral leg405 and/oripsilateral leg404. Such challenges may also be presented in the blood flow passageways defined by graftmain body402 of thebifurcated graft401 andtubular graft11 embodiments. This may in turn negatively affect the patency of the cuff and channel lumens such that the cuffs and channels cannot adequately be filled with inflation material. Second, the outertubular member431 can be more difficult to retract proximally relative to innertubular member430 when thedelivery system400 is disposed in such angled and/or tortuous anatomies.
• The delivery method discussed with respect to FIGS.[0271]34-50 teaches that the steps of deploying the distal and proximal self-expanding members are accomplished prior to the step of inflating the graft cuffs and channels. A variation in this deployment sequence that is useful for tortuous or angled patient anatomies is discussed below in conjunction with the delivery system components of FIGS. 31A, 31B and58-60, although any of the delivery systems or their components described herein may employ this sequence variation.
• During the delivery procedure, after the first and second distal[0272]self expanding members411 and412 have been released, the operator removesrelease strand tube718 from the body through the leftfemoral access hole537. This exposesrelease strand710,secondary release wire719, andshield line720.
• Next, the[0273]shield line720 is pulled in aproximal direction729 by the operator to removeshield724 from the contralateral legproximal end417, exposing self-expandingmember408. A buttress, which can be a tubular member such as a catheter or the like, is threaded on the remainingsecondary release wire719 andrelease strand710 and advanced distally until it physically abuts theproximal end483 of the secondarybelt support member454. This provides a relatively stiff column that the operator may use to move the graftcontralateral leq405 in a distal direction as well as react the force necessary to deploy self-expandingmember408 by retractingrelease wire719.
• The operator next detaches Luer-type fitting or cap[0274]521 fromflexible fill catheter523 and removes ripcord510 fromchannel418.Graft401 cuffs and channels may then be filled with inflation material as previously described. When the inflation material is radiopaque or otherwise observable in vivo, the operator may interrogate the shape of thegraft401 and the various cuffs and channels under fluoroscopy or other suitable imaging technique to determine qraft limb patency, the sufficiency of graft cuff and channel inflation, and whether any folds or other irregularities in the graft exist so that they may be corrected. When observed under fluoroscopy, the operator may adjust the C-arm of the fluoroscope to interrogategraft401 from a number of angles.
• If necessary, and after cuff and channel inflation but before proximal self-expanding member deployment, the operator may manipulate both the buttress catheter and/or[0275]release strand710 to push or pull, respectively, the qraft contralateral leq into. the proper position. By making fine adjustments in either direction, the operator may remove or add slack in the graftcontralateral leg405 and ensure optimal qraft placement and patency. To minimize operator confusion, therelease strand710 andstent release wire719 may be different lenqths, color coded, flagged or otherwise labeled, etc. We have found that making thestent release wire719 shorter thanrelease strand710 helps in maintaining optimal operator orientation with respect to the various components of the qraft delivery system.
• When the operator is satisfied with the position, patency, and appearance of[0276]graft401, contralateral self-expandingmember408 may be deployed by applying tension in theproximal direction729 onsecondary release wire719 so thatsecondary belt716 releases proximal self-expandingmember408 in the manner previously described.
• Similarly, the operator next may adjust the position of the[0277]ipsilateral leg404 ofgraft401 by adjusting the position of primarybelt support member452 and then release proximal self-expandingmember407 of theipsilateral leg404 as described herein.
• To withdraw the delivery apparatus,[0278]guide wire530 is partially withdrawn in the proximal direction throughnosepiece434 intoguide wire tube436 to a point proximal ofcuff413. This prevents theguide wire530 from possible interference with proper inflation ofcuff413. Next, thedistal end487 of theinflation tube444 may be disengaged from theinflation port421 by pulling on aproximal end491 ofretention wire488 as previously discussed. Using the buttress to push on belt support memberproximal portion483 if necessary, the operator may then proximally withdraw the primarybelt support member452 overguide wire530 with the secondarybelt support member454 following. Finally,guide wire530 is removed through left and right femoral access holes537,531, which may then be repaired using conventional techniques.
• It is clear to those of skill in the art that although particular techniques and steps are described herein that we have found to be useful, variations in the order and techniques in which the various deployment steps described herein are within the scope of the present invention.[0279]
• While particular forms of the invention have been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be so limited.[0280]

Claims (1)

We claim the following:

1. A delivery system for a bifurcated intracorporeal device comprising:

an elongate shaft having a proximal section and a distal section with the distal section comprising:

an elongate primary belt support member;

at least one primary belt secured to the primary belt support member configured to be circumferentially disposed about a bifurcated intracorporeal device so to at least partially constrain the device;

a primary release member configured to engage and releasably secure the primary belt in a constraining configuration;

at least one elongate secondary belt support member disposed adjacent the elongate primary belt support member and secured to the primary belt support member with a releasable hinged joint;

at least one secondary belt secured to the secondary belt support member configured to be circumferentially disposed about a bifurcated intracorporeal device so to at least partially constrain the device; and

a secondary release member configured to engage and releasably secure the secondary belt in a constraining configuration.

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