US20090005852A1 - Methods and Devices for Placing a Conduit in Fluid Communication with a Target Vessel - Google Patents

Abstract

Methods and devices for placing a conduit in fluid communication with a target vessel and a source of blood, such as the aorta or a heart chamber. The device may be actuated using one hand to place the conduit. The invention allows air in the conduit to be removed prior to placement of the conduit. The invention deploys the conduit in the target vessel by moving a sheath in a distal direction and then in a proximal direction. A conduit is provided with a reinforcing member to prevent kinking of the conduit, and a structure for preventing blockage of the conduit by tissue. A vessel coupling may be used to secure a conduit to a target vessel so as to preserve native blood flow through the vessel, and the conduit may be placed in fluid communication with a target vessel via a laparoscopic or endoscopic procedure.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 09/850,883, filed May 7, 2001, which is a continuation of U.S. patent application Ser. No. 09/304,149, filed May 3, 1999, which is a continuation-in-part of application Ser. No. 09/232,103, filed on Jan. 15, 1999 and entitled “Methods and Devices for Forming Vascular Anastomoses,” the entire subject matter of which is incorporated herein by reference. This application is also a continuation-in-part of application Ser. No. 09/232,062, filed on Jan. 15, 1999 and entitled “Methods and Devices For Bypassing an Obstructed Target Vessel by Placing the Vessel in Communication with a Heart Chamber Containing Blood,” the entire subject matter of which is also incorporated herein by reference.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The invention relates to methods and devices for placing a conduit in fluid communication with a lumen of a target vessel, and more particularly methods and devices for placing such a conduit in fluid communication with a target vessel and a source of blood.
• 2. Description of the Related Art
• Despite the considerable advances that have been realized in cardiology and cardiovascular surgery, heart disease remains the leading cause of death throughout much of the world. Coronary artery disease, or arteriosclerosis, is the single leading cause of death in the United States today. As a result, those in the cardiovascular field continue to search for new and improved treatments.
• Coronary artery disease is currently treated by interventional procedures such as percutaneous transluminal coronary angioplasty (PTCA), atherectomy and coronary stenting, as well as surgical procedures including coronary artery bypass grafting (CABG). The goal of these procedures is to reestablish or improve blood flow through occluded (or partially occluded) coronary arteries, and is accomplished, for example, by enlarging the blood flow lumen of the artery or forming a bypass that allows blood to circumvent the occlusion. What procedure(s) is used typically depends on the severity and location of the blockages. When successful, these procedures restore blood flow to myocardial tissue that had not been sufficiently perfused due to the occlusion.
• Another treatment that has been recently proposed places the target vessel in fluid communication with a heart chamber, for example, the left ventricle. The target vessel and the heart chamber may be communicated by a conduit passing through the myocardium. Some of the challenges associated with such procedures include proper positioning of the conduit in the myocardium as well as correct placement of the conduit in a coronary artery.
• As shown by these and other attempts to develop new and improved treatments that may be used to deliver blood to myocardial tissue, there remains a need in the art for methods and devices that may be used to place a conduit in fluid communication with a target vessel and a source of blood.
SUMMARY OF THE INVENTION
• According to one embodiment of the invention, methods and devices are provided for placing a conduit in fluid communication with a target vessel. One preferred method includes steps of providing a conduit having a first end, a second end and a lumen, the conduit being supported by a conduit delivery device. A portion of the device is positioned adjacent a target vessel in a patient's vascular system, one of the first and second ends of the conduit is placed in fluid communication with the target vessel, and the conduit is removed from the delivery device. The steps of positioning the portion of the conduit delivery device adjacent the target vessel and placing one of the first and second ends of the conduit in fluid communication with the target vessel are performed using one hand.
• One preferred device includes a conduit having a first end, a second end and a lumen, wherein the conduit is movable between deployed and non-deployed positions and one end of the conduit is adapted to be placed in fluid communication with a target vessel. A sheath overlies at least a portion of the conduit and holds the portion in the non-deployed position. A first actuator imparts relative movement to the conduit and the sheath in order to allow the portion of the conduit to move to the deployed position. A sheath removal mechanism is provided for removing the sheath after the conduit has moved to the deployed position. The first actuator and the sheath removal mechanism are operable using one hand to place the conduit in fluid communication with the target vessel and remove the sheath from the target vessel.
• According to another embodiment of the invention, methods and devices are provided for placing a conduit in fluid communication with a target vessel and a source of blood. One preferred method includes steps of providing a conduit having a first end, a second end and a lumen, placing the first end of the conduit in fluid communication with the source of blood, allowing blood to flow into the lumen of the conduit to force substantially all air from the conduit, and placing the second end of the conduit in fluid communication with the target vessel.
• One preferred device includes a conduit having a first end, a second end and a lumen, wherein the first end of the conduit is adapted to be placed in fluid communication with a target vessel and the second end of the conduit is adapted to be placed in communication with a source of blood. A support shaft has a section that is removably coupled to the first end of the conduit for placing the first end of the conduit in fluid communication with the target vessel, but de-coupled from the second end of the conduit to allow the second end of the conduit to be placed in communication with the source of blood prior to placing the first end of the conduit in fluid communication with the target vessel.
• According to another embodiment of the invention, methods and devices are provided for establishing a conduit to place a coronary vessel in fluid communication with a heart chamber containing oxygenated blood. One preferred method includes steps of placing a conduit in fluid communication with a heart chamber containing oxygenated blood, wherein at least a major portion of the length of the conduit is disposed exterior to the heart wall. The conduit is also placed in fluid communication with a lumen of a coronary vessel, and is secured to the coronary vessel by a sutured anastomosis so as to place the coronary vessel in fluid communication with the heart chamber.
• According to another embodiment of the invention, methods and devices are provided for deploying a conduit in a target vessel. One preferred method includes steps of providing a conduit having a first end, a second end and a lumen, wherein the conduit is movable between deployed and non-deployed positions and at least a portion of the conduit is held in the non-deployed position by a retention member. At least the non-deployed portion of the conduit is placed in a lumen of a target vessel, and the retention member is moved in a first direction with respect to the conduit to move the non-deployed portion of the conduit to the deployed position. The retention member is moved in a second direction that is substantially opposite the first direction to remove the retention member from the target vessel.
• One preferred device includes a conduit having a first end, a second end and a lumen, wherein the conduit is movable between deployed and non-deployed positions and one end of the conduit is adapted to be placed in fluid communication with a target vessel. A retention member overlies at least a portion of the conduit to hold the portion in the non-deployed position. An actuator is coupled to the retention member and is moved in a first direction to move the retention member and allow the portion of the conduit to move to the deployed position. The actuator is then moved in a second direction to remove the retention member from the target vessel, the second direction being transverse to the first direction.
• According to another embodiment of the invention, methods and devices are provided for placing a conduit in fluid communication with a target vessel while preserving native blood flow through the target vessel. One preferred method includes steps of providing a vessel coupling and a conduit, wherein the vessel coupling has a first portion configured to secure the conduit to a target vessel so that the conduit is in fluid communication with the target vessel. The vessel coupling is moved generally along a first direction to place the first portion of the vessel coupling at least partially within the lumen of the target vessel, and the first portion of the vessel coupling is then moved generally along a second direction within the lumen of the target vessel to deploy the vessel coupling and secure the conduit to the target vessel, wherein the second direction is transverse to the first direction.
• One preferred device includes a vessel coupling including a first portion joined to a second portion, wherein the first portion of the vessel coupling is sized and configured to be attached to a target vessel while allowing native blood flow through the target vessel to move past the site of attachment. The second portion of the vessel coupling is sized and configured to be coupled to a conduit that is adapted to form a flow path between the target vessel and a source of blood. The first portion of the vessel coupling includes a plurality of support members sized and configured to engage a wall of the target vessel, each support member including a plurality of generally straight support struts.
• According to another embodiment of the invention, methods and devices are provided for forming a blood flow path through tissue. One preferred device includes a tubular member having a first end, a second end and a lumen, wherein the tubular member is configured to be placed in tissue and the lumen of the tubular member is sized and configured to receive a conduit adapted to form a blood flow path through the tissue. At least one of the first and second ends of the tubular member is configured to extend through the tissue so as to place the conduit in fluid communication with a hollow body structure containing blood, and a structure is coupled to the one end of the tubular member for maintaining the one end substantially open. The structure includes at least one opening through which blood from the hollow body structure may enter the conduit.
• According to another embodiment of the invention, methods and devices are provided for placing a conduit in fluid communication with a target vessel in a patient's vascular system by passing a device through a port located between adjacent ribs. One preferred method includes steps of providing a conduit having a first end, a second end and a lumen, wherein the conduit is supported by a conduit delivery device having a portion that is sized and configured to be passed through a port located between adjacent ribs in a patient's body, and passing the portion of the conduit delivery device through the port to a location adjacent the target vessel. One of the first and second ends of the conduit is placed in fluid communication with a lumen of the target vessel, the conduit is removed from the conduit delivery device, and the conduit delivery device is removed from the port.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
• Various other aspects, features, benefits and advantages of the invention will be better understood from the following detailed description of preferred embodiments thereof, taken in conjunction with the accompanying drawing figures, wherein:
• FIG. 1 is a perspective view of a device constructed according to one embodiment of the invention for placing a conduit in fluid communication with a target vessel;
• FIG. 2 is an exploded perspective view of the device shown inFIG. 1;
• FIG. 3 is a longitudinal sectional view of the device shown inFIG. 1;
• FIGS. 3A and 3B are transverse sectional views taken, respectively, along lines A-A and B-B inFIG. 3;
• FIG. 4 is an enlarged, fragmentary longitudinal sectional view of the device shown inFIGS. 1 and 3;
• FIGS. 5A-5D are sectional views sequentially illustrating an exemplary use of the device shown inFIG. 3;
• FIG. 6 is a perspective view of a conduit that has been placed in fluid communication with a target vessel as shown inFIGS. 5A-5D, the conduit including a vessel coupling disposed on the exterior of the conduit;
• FIG. 6A is a perspective view of the conduit shown inFIG. 6, wherein the vessel coupling is shown disposed within the conduit;
• FIG. 7 is a perspective view of a conduit that has been placed in fluid communication with a target vessel and a source of blood according to another embodiment of the invention, wherein the source of blood is the aorta;
• FIG. 8 is a perspective view of a conduit that has been placed in fluid communication with a target vessel and a source of blood according to another embodiment of the invention, wherein the source of blood is the left ventricle and the conduit has an end configured to be placed in the myocardium;
• FIG. 9 is an enlarged perspective view of an end of the conduit that is shown placed in the left ventricle inFIG. 8;
• FIG. 10 is a perspective view of a fitting mounted to the end of the conduit shown inFIG. 9;
• FIG. 11 is a sectional view illustrating the end of the conduit shown inFIG. 9 placed in the myocardium;
• FIG. 12 is a sectional view of a portion of a conduit constructed according to another embodiment of the invention, wherein the end of the conduit is configured for placement in the myocardium;
• FIG. 12A is an enlarged view of the portion encircled inFIG. 12;
• FIG. 13 is a perspective view of a device constructed according to another embodiment of the invention, wherein the device includes the conduit shown inFIG. 9;
• FIG. 14 is a perspective view of a device constructed according to another embodiment of the invention for placing a conduit in fluid communication with a target vessel and a source of blood, wherein the device allows placement of either end of the conduit first;
• FIG. 15 is a perspective view of a device constructed according to yet another embodiment of the invention for placing a conduit in fluid communication with a target vessel, wherein the device is sized and configured for use in a laparoscopic or endoscopic procedure;
• FIG. 16 is a perspective view illustrating the device shown inFIG. 15 being used in a minimally invasive procedure.
• FIG. 17 is a perspective view of a conduit that has been placed in fluid communication with a target vessel according to another embodiment of the invention, wherein native flow through the target vessel is substantially preserved;
• FIG. 18 is a perspective view of a conduit including a stent constructed according to another embodiment of the invention, wherein the stent places the conduit in fluid communication with a target vessel so as to substantially preserve native flow through the target vessel;
• FIG. 19 is a flat pattern elevation view showing one end of the stent shown inFIG. 15;
• FIG. 20 is a perspective view of a conduit including a stent constructed according to another embodiment of the invention, wherein the stent places the conduit in fluid communication with a target vessel so as to substantially preserve native flow through the target vessel; and
• FIG. 21 is a flat pattern elevation view showing one end of the stent shown inFIG. 20.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
• Referring toFIGS. 1-4, a device constructed according to one preferred embodiment of the invention is indicated generally by thereference numeral10. Thedevice10 is used to place a conduit in fluid communication with a target vessel, the conduit also preferably being placed in fluid communication with a source of blood. As used herein, source of blood refers to any structure containing blood, although a structure containing oxygenated blood, i.e., blood containing some level of oxygen, is preferred. For example, the source of blood may be a heart chamber while the target vessel may be a coronary artery or vein or another vessel.
• Thedevice10 comprises ahandle12, ashaft assembly14 and an actuator assembly16 (FIGS. 2-4). Theshaft assembly14 may be relatively flexible to permit it to bend during use, or it may be substantially rigid. The degree of flexibility imparted to theshaft assembly14 of thedevice10, as well as the dimensions and shape of thedevice10, may vary depending on the particular application and user preference.
• Thedevice10 could be formed with ashaft assembly14 that is curved, malleable or bendable to a selected configuration, or articulated with a movable portion that may be controlled or steered by known mechanisms, for example, mechanisms used to steer catheters or guide wires. As an example, the device could have a curved shaft assembly constructed according to the teachings in co-pending, commonly-owned application Ser. No. 09/304,141 (attorney docket no. 008), filed on May 3, 1999 and entitled “Methods and Devices for Forming a Conduit Between a Target Vessel and a Blood Source,” the entire subject matter of which is hereby incorporated by reference.
• The application of the invention illustrated in the Figures places a conduit in fluid communication with a target vessel and a source of blood. The term conduit refers to a flow path established between the target vessel and the blood source and includes structure that defines (either partially or completely) the flow path. A conduit constructed according to the invention may comprise one or more sections, each of which sections may comprise various materials. It will be appreciated that the specific conduit configurations illustrated in connection with preferred embodiments described herein is for sake of example and is not intended to limit the scope or application of the invention.
• The illustratedconduit18 includes aproximal end20, adistal end22 and alumen24. Theconduit18 is deployed in a target vessel and preferably includes a vessel coupling that is configured to be secured to the target vessel. It should be understood, however, that the invention may be practiced without using a vessel coupling, for example, by securing the conduit to the target vessel with a sutured anastomosis created by hand or an automated suturing device, biologically compatible adhesives, fasteners, etc. A vessel coupling is preferred, however, to facilitate relatively easy and rapid attachment of the conduit to the target vessel as compared to creating a hand-sewn anastomosis. Also, the conduit may comprise tissue, synthetic vascular graft material, or a combination of tissue and synthetic vascular graft material. Thus, in a basic embodiment, the invention could comprise a tissue or synthetic conduit that is placed in communication with a source of blood such as the left ventricle, and hand-sutured to a target vessel such as a coronary artery.
• In the illustrated embodiments, theconduit18 comprises a length of synthetic vascular graft material, such as ePTFE, PTFE or Dacron, or another material that may be used to form a conduit that conveys blood, for example, silicone, PVA or polyurethane. Theproximal end20 of theconduit18 is adapted to be placed in fluid communication with a source of blood (not shown inFIGS. 1-4) and for that purpose may include means for securing the conduit in place with respect to the blood source, such as a device configured to be implanted and fixed in tissue located adjacent the blood source. Alternatively, theproximal end20 of theconduit18 could be secured to tissue by other means, for example, any of the aforementioned means for securing the distal end of theconduit18 to the target vessel.
• In the most preferred embodiment, the conduit is secured to the target vessel by a substantially suture-free attachment, which means that the attachment is not a conventional hand-sewn anastomosis created by suturing the members together. As such, although some suture may be used in the preferred embodiment, the vessel coupling is attached to the target vessel by means other than a typical, hand-sewn sutured connection. The invention, however, may be practiced using suture as the means for attaching a conduit comprising tissue or synthetic vascular graft material to a target vessel.
• Theconduit18 includes a vessel coupling that attaches the conduit to the target vessel, the vessel coupling preferably being expandable so that it may be collapsed for introduction into the vessel and then expanded against the vessel wall. It will be understood, however, that the invention may be practiced with a non-expandable vessel coupling, such as a rigid tubular member securely engaged with the wall of the target vessel, for example, by first dilating the vessel wall to place the element and then allowing the vessel wall to move back and snugly engage the exterior of the element.
• The expandable vessel coupling moves between collapsed and expanded orientations and in the preferred embodiment comprises astent26. Thestent26 could be formed of various materials including nitinol, stainless steel, tantalum or titanium. As an example, thestent26 may be a self-expanding nitinol stent joined to a liner orlayer28 of teflon (PTFE) or expanded teflon (ePTFE) to form theconduit18. Thestent26 preferably includes a plurality of struts that permit the stent to collapse and expand, although other stent constructions may be used; for example, the stent could be wire-formed or could comprise a flat sheet of material that is unrolled to an expanded orientation.
• As an example, the stent may be formed by subjecting a tube of suitable material to any of various procedures such as laser cutting, EDM (electrical discharge machining), photochemical etching, etc. The stent/tube material is preferably nitinol, but may be titanium, tantalum, etc. It may be desirable to further process or finish the cut stent to remove burrs or surface irregularities, for example, by acid etching, electropolishing, or abrasive blasting. The stent may then be placed in its collapsed orientation by cooling (e.g., with liquid nitrogen), coupled to a liner and loaded onto a delivery device, and then deployed in a target vessel. The liner of the conduit, for example, may comprise ePTFE having an inner diameter within the range of from about 1 mm to about 5 mm, and more preferably about 2 mm to about 4 mm, a wall thickness of about 0.2 mm, and an internodal distance or pore size in the range of from about 20 μs to about 100 μs.
• Theliner28 is secured to thestent26 by any suitable means, for example, one or more lengths of suture (not shown) that pass through the liner wall and the wall of the stent. Other suitable means for securing the two components include biologically compatible adhesives, ultrasonic welding, clips or fasteners, weaving the liner through the stent elements, tying the liner to the stent elements, etc. As shown inFIG. 2, thestent26 is preferably aligned so as to extend a desired amount along part of thedistal end22 of theconduit18. This relative position is preferred as it allows part of thestent26 to extend through the wall of the target vessel when theconduit18 has been deployed, this portion of the stent serving to hold the junction open to maintain fluid communication. However, it will be appreciated that thestent26 andliner28 could overlap to a lesser or greater extent than that shown in the Figures, and the stent may or may not extend through the target vessel wall.
• For example, thestent26 could extend along substantially the entire length of theconduit18, along only the two end portions of the conduit, or the conduit could include discrete sections that comprise only stent or liner material. In the exemplary embodiment shown inFIGS. 1-4, theconduit18 has a distal section defined by stent and liner material while the remaining length of theconduit18 is defined by liner material alone (as seen fromFIGS. 3A-3B). Also, while thestent26 is shown disposed outside theliner28 inFIGS. 1-4, it will be recognized that the stent may be disposed within the liner. Finally, while the illustratedconduit18 includes only thestent26 and asingle liner28, an additional layer(s) of material, such as another layer of PTFE or ePTFE, a layer of silicone, or another stent, may be included as well.
• Referring toFIG. 2, theconduit18 is supported by theshaft assembly14, and more particularly by asupport member30 which forms part of theshaft assembly14. Thesupport member30 may be a rod or shaft that is sized and configured to mount theconduit18, and more specifically thestent26 andliner28.FIG. 2 shows (in phantom) theconduit18 mounted on thesupport member30 in its collapsed orientation. Thesupport member30 has aproximal end32 and adistal end34, theproximal end32 being fixed to the handle12 (as shown inFIGS. 3-4). Thedistal end34 is preferably provided with a stop for maintaining theconduit18 in position. The stop may be in the form of apiston36 carried by thesupport member30 and sized to generally correspond to the collapsed diameter of theconduit18. The illustratedsupport member30 also includes abore38 extending through the length of the member (FIG. 2).
• In the illustrated embodiment, thebore38 in thesupport member30 receives ashaft40 provided with a retention mechanism for retaining all or a portion of the conduit18 (and in particular the stent26) in its collapsed orientation during introduction into the lumen of the target vessel. A preferred retention mechanism comprises asheath42 sized and configured to be placed over a collapsed portion of theconduit18. A nose cone dilator having one or more tapered surfaces for introducing the device into the lumen of a target vessel is preferably disposed on theshaft40 distal to thesheath42. The nose cone dilator may comprise any suitable material, a soft, floppy atraumatic material being preferred. It should be noted that alternative or additional means for dilating the vessel may be used or the dilator may be omitted altogether, although some form of dilator is preferably used. Thesheath42 is preferably fixed to theshaft40 but could instead be removably supported by the shaft. Thesheath42 may be formed of any suitable thin-walled, flexible material, e.g., polyolefin, nylon, polyimide, PEEK, or Hytrel.
• It will be appreciated that the sheath could be constructed so as to be removable in a manner the same as or similar to that disclosed in co-pending, commonly-owned application Ser. No. 09/232,103, filed on Jan. 15, 1999 and entitled “Methods and Devices for Forming Vascular Anastomoses,” or co-pending, commonly-owned application Ser. No. 09/232,062, filed on Jan. 15, 1999 and entitled “Methods and Devices For Bypassing an Obstructed Target Vessel by Placing the Vessel in Communication with a Heart Chamber Containing Blood,” the subject matter of which applications has been incorporated herein by reference.
• Additionally, the sheath could be constructed according to the disclosure in co-pending, commonly-application Ser. No. 09/304,141 (attorney docket no. 008), filed on May 3, 1999 and entitled “Methods and Devices for Forming a Conduit Between a Target Vessel and a Blood Source,” the entire subject matter of which application is incorporated herein by reference.
• As shown inFIG. 2, the proximal portion of theshaft40 is in the form of arack44 which forms part of theactuator assembly16. Theactuator assembly16 is used to impart relative movement to theconduit18 andsheath42 in order to deploy theconduit18 in the target vessel. Therack44 has teeth for engaging the teeth of apinion46 carried by anactuator48. In the illustrated embodiment, theactuator48 is a lever pivotally coupled to thehandle12 by apivot pin50. Theactuator48 is pivoted with respect to thehandle12 and transmits motion to theshaft40 via the mating gear teeth on therack44 andpinion46. Theactuator assembly16 is constructed so that pivoting theactuator48 moves theshaft40 and sheath42 a desired amount in a desired direction to deploy the conduit, which according to the preferred embodiment may be done using one hand, as described more fully below. Other methods of actuation may of course be used, such as those using cable systems, alternative lever assemblies, etc. Thedevice10 also preferably includes a locking mechanism which may be in the form of asafety pin52 movably disposed in abore54 in thehandle12. Thesafety pin52 can be moved into or out of a mating bore56 formed in theactuator48 to either lock or unlock theactuator48 with respect to thehandle12.
• Thedevice10 also includes a mechanism that aids in removing the device, and in particular thesheath42, from the target vessel. A preferred mechanism is indicated generally by thereference numeral58 inFIG. 2 and comprises atubular body60 having abore62 sized to be slid over thesupport member30. Thebody60 has aproximal end64 and adistal end66, the latter being provided with amember68 that is configured to be coupled to thesheath42. Themember68 preferably has a tapered contour that allows themember68 to be slid into the open end of thesheath42. Themember68 may have agroove70 or other portion that engages the edge of thesheath42 to provide a smooth outer profile for withdrawing the sheath from the lumen of the target vessel.
• Theproximal end64 of thetubular body62 is provided with an actuatingportion72 for moving thebody62 andmember68 with respect to theshaft40. The actuatingportion72 may be connected to thetubular body62 by astem74 which extends through aslot76 formed in thehandle12. Thebody62 may be movable in one or more directions; in the illustrated embodiment, thetubular body62 is moved distally (to the left inFIG. 3) along the longitudinal axis of the device to engage themember68 and thesheath42. The entire device is then moved proximally with thesheath42 passing through theconduit18.
• As can be seen fromFIG. 1, the relative position of theactuator48 ofassembly16 and the actuatingportion72 ofsheath removal mechanism58 allows them to be operated using one hand. Accordingly, a surgeon may place theconduit18 in fluid communication with the target vessel, remove the sheath42 (or other retention mechanism) from the conduit, and remove thedevice10 from the vessel using only one hand. This aspect of the invention provides the user with a free hand unlike an instrument requiring two-handed operation, and thus adds flexibility to enable relatively quick and easy conduit deployment. It will be recognized that the invention encompasses other device configurations that allow the conduit to be deployed and/or the device to be removed by one-handed operation, the particular device shown in the Figures being merely exemplary.
• FIGS. 3-4 show in more detail the internal construction of the illustrateddevice10.FIG. 3 shows thehandle12 andactuator assembly16, whileFIGS. 3A,3B and4 show details of theshaft assembly14. Thehandle12 preferably includes achamber80 that receives therack44 andpinion46 ofactuator assembly16 and allows them to move upon actuation of the device. Therack44 orpinion46 may be constrained by a track or guide so as to move along a certain path or they may simply be disposed in thechamber80 in a free-floating manner.
• It should be noted that thedevice10 may be introduced into a target vessel in various ways. For example, in the illustrated embodiment, thehandle12 of thedevice10 is provided with abore82 that may receive an incising element (not shown) having a sharpened tip for penetrating the wall of the target vessel. SeeFIG. 3. Thebore82 opens into thechamber80 and is aligned with abore84 provided in the shaft40 (or another component of the shaft assembly14). The incising element could be a separate component that is passed through thebores82,84; alternatively, the incising element could be formed as an integral part of the device. The invention could be used with other incising elements or components, for instance, the incising assembly disclosed in application Ser. No. 09/232,103 and application Ser. No. 09/232,062, the entire subject matter of which applications has been incorporated by reference herein.
• Providing theshaft assembly14 of the device with thebore84 allows the incising element to be extended and retracted and also protects theconduit18 by limiting or preventing its contact with other components of the device. Additionally, either or both of thebores82,84 may be configured to act as a flashback lumen that indicates when the device has entered a lumen containing blood, for example, a coronary artery or heart chamber. Thebores82,84 may be disposed to provide blood flash irrespective of whether the bores receive an incising element or an additional member(s), for example, means for introducing the device into the target vessel such as a guide wire or guide catheter. In addition, it will be appreciated that the device may be used without an incising element, for example, by placing the shaft assembly through a surgical incision in the target vessel wall.
• Turning again toFIGS. 3-4, thedevice10 is depicted in a first position (also shown inFIG. 1) wherein theconduit18 has not yet been deployed in a target vessel. In this position thesheath42 overlies a selected portion of theconduit18 and holds thestent26 andliner28 in a collapsed orientation. The remaining portions of thestent26 and theliner28 extend outside of thesheath42 and assume their expanded orientation. As seen inFIG. 3A, thesheath42 contacts the outer surface of the portion of thestent26 to maintain that portion collapsed. In the illustrated embodiment, theliner28 is disposed withinstent26, although, as noted above this is only one possible construction. Also, the portion of theliner28 within thesheath42 is preferably folded or otherwise collapsed to a lower profile (although for sake of clarityFIG. 3A does not show theliner28 folded to such a profile).
• Theshaft40 extends through thebore82 in thehandle12 and is disposed, preferably coaxially, within thebore38 in thesupport member30. Theconduit18 is loaded on thesupport member30 and the desired portion of the conduit is collapsed to a low profile orientation, thepiston36 abutting thedistal end22 of theconduit18. Thesheath42 is placed over the collapsed portion of theconduit18 as shown inFIG. 1. Theactuator48 is moved toward thehandle12 which rotates thepinion46 and drives therack44 distally (to the left inFIGS. 3-4). This moves thesheath42 to uncover thestent26 and deploy theconduit18. Moving thesheath42 in this direction will tend to move theconduit18 in the same direction due to friction between thestent26 and thesheath42. Thepiston36, however, prevents thestent26 from moving with the sheath42 (as the piston is fixed to the handle12). As a result, thesheath42 is moved while theconduit18, including thestent26, remains substantially stationary (and preferably stationary) with respect to thehandle12.
• In the illustrated embodiment theactuator48 is pivoted toward thehandle12; however, the device could be constructed so that theactuator48 is moved in a different manner or direction to deploy the conduit. For example, theactuator assembly16 could comprise a trigger-like member that is slideable with respect to thehandle12, or a pair of scissors-like members that are moved together (or apart) to actuate the device. An actuator that is operable using one hand is preferred, although not necessary to practicing various aspects of the invention. At any rate, theactuator assembly16 is preferably coupled to theshaft assembly14 so as to produce motion that is generally along the longitudinal axis of the device, thereby providing the device with a small profile, although a non-longitudinal actuator motion could also be used.
• FIGS. 5A-5D illustrate an exemplary application of thedevice10 wherein a conduit is placed in fluid communication with a target vessel TV.FIG. 5A shows the distal portion of theshaft assembly14 inserted through an opening in the target vessel wall W and into the lumen of the target vessel. Although not shown, an incising component may be used to form the opening in the wall W. Thedevice10 is preferably introduced into the lumen by dilating the opening in the wall W and cannulating the target vessel TV.
• FIG. 5B shows the device after thesheath42 has been moved distally to expose the portion of theconduit18 that is covered by the sheath inFIG. 5A. Theactuator48 is moved relative to thehandle12 from the position shown inFIG. 1 to move thesheath42 and allow thestent26 to assume its expanded orientation. Thepiston36 prevents thestent26 from moving distally with thesheath42. This step is preferably carried out so as to prevent or minimize trauma to the target vessel TV, so the nose cone dilator is formed of a relatively soft and flexible material and has an atraumatic shape, although stiff or rigid materials may be used as well. In the position shown inFIG. 5B, thestent26 is fully expanded and secures the deployedconduit18 to the target vessel TV in fluid communication therewith, preferably via a sealed connection between the two structures.
• As can be seen fromFIG. 5B, thepiston36 is disposed in (or near) the proximal end of thesheath42 after thestent26 has been deployed in the target vessel TV. As such, thepiston36 may block the open end of thesheath42 and interfere with engagement between thesheath removal mechanism58 and thesheath42. Accordingly, it may be necessary to first impart relative movement to thepiston36 and thesheath42 in order to present an open proximal end of the sheath to theremoval mechanism58. This may be achieved in various ways. For example, in the illustrated embodiment thepiston36 is fixed to thehandle12 viasupport member30. Theactuator48 thus may be moved away from thehandle12 to move thesheath42 proximally with respect to the handle and thepiston36. Alternatively, thepiston36 could be coupled to the handle so as to be movable with respect thereto, e.g., by a separate actuator. In either case thepiston36 is moved relative to thesheath42, an exemplary result of such movement being shown inFIG. 5C.
• It will be recognized that other constructions may of course be used. For example, rather than imparting relative movement to thepiston36 and thesheath42, thesheath removal mechanism58 could be configured to engage the edge of thesheath42 without moving the piston. Also, themechanism58 could be configured to engage thepiston36 directly and provide a smooth outer profile to the distal portion of theshaft assembly14.
• FIG. 5C shows thesheath removal mechanism58 after it has been moved in the direction of the arrow into engagement with the open end of thesheath42 to form a smooth atraumatic profile that prevents or minimizes damage to the vessel or theconduit18. In the illustrated embodiment the edge of thesheath42 rests in thegroove70 and transitions into the proximal portion of themember68. The next step, as shown inFIG. 5D, is to move theshaft assembly14 proximally in the direction of the arrow to remove the device and deploy theconduit18 in the target vessel TV. Theremoval mechanism58 prevents the sheath from catching on the stent struts. Removing the device results in a preferably fluid-tight attachment that communicates the lumen of theconduit18 with the lumen of the target vessel TV.
• FIG. 6 is a perspective view of the exterior of the target vessel TV and theconduit18. Thedistal end22 of theconduit18 is positioned in the lumen of the target vessel TV with thestent26 expanded against the vessel wall W. Theliner28 is secured to thestent26 and thus is held open by the expanded stent to provide a fluid path for blood flowing in the direction of the arrows. The amount of theconduit18 that is positioned in the lumen of the target vessel TV may vary from that shown but is preferably sufficient to ensure a secure attachment between the conduit and the vessel. Similarly, the amount of thestent26 that extends outside the target vessel TV may vary from that shown inFIG. 6. However, as noted above it may be desirable to allow a sufficient portion of thestent26 to extend through the opening in the target vessel wall to prevent the vessel wall from collapsing theconduit18.
• FIG. 6A shows an alternative embodiment wherein thestent26 is disposed on the interior of theconduit18, and specifically within the interior of theliner28. In this arrangement theliner28 is forced open by the expanded stent to provide an open fluid path for blood flowing in the direction of the arrows. It should be noted that in this embodiment theliner28 may be secured to thestent26 less vigorously as the stent presses the liner against the target vessel wall, as opposed to the stent pulling the liner toward the wall (as in the embodiment ofFIG. 6). It will be appreciated that other constructions and configurations may be used as well.
• FIG. 7 is an anterior view of a heart H showing the left ventricle LV, right atrium RA, aorta A, pulmonary trunk PT and pulmonary veins PV. The left coronary artery, including the circumflex branch and the left anterior descending branch LAD, is visible in this view, as is the right coronary artery RCA. The coronary arteries run along the heart wall and deliver oxygenated blood to the myocardial tissue. An occlusion or blockage O partially (or completely) obstructs the lumen of the LAD, which results in inadequate or no blood flow to the heart wall tissue fed by the portion of the LAD that is downstream of the occlusion O.
• Thedistal end22 of theconduit18 has one end secured to the LAD (distal to the occlusion O) by thestent26 as described above. Theproximal end20 of theconduit18 is secured to a source of blood, which in this case is the aorta A. Theproximal end20 may be attached to the aorta A via a sutured anastomosis P created by an instrument or in a hand-sewn manner. Other means for attaching the end of theconduit18 include a vessel coupling such as a stent, other fasteners, biologically compatible adhesives, etc. Also, as an example, the length of the conduit extending between the aorta and the coronary vessel may be in the range of from about 5 cm to about 8 cm (including the portion of the conduit disposed in the vessel).
• It will be appreciated that the particular target vessel and source of blood shown inFIG. 7 is only exemplary as there will be numerous applications for the methods and devices disclosed herein. For example,FIG. 8 illustrates a heart wherein the invention has been used to place a target vessel in fluid communication with an alternative source of blood. Thedistal end22 of theconduit18 is secured to the LAD as inFIG. 7; however, theproximal end20 of the conduit is placed in fluid communication with a heart chamber containing blood, which in this embodiment is the left ventricle LV. As a result, blood flows from the left ventricle LV into theconduit18 and into the target vessel distal to the occlusion O. As an example of one possible configuration, the length of the conduit extending between the heart chamber and the coronary vessel may be in the range of from about 3.5 cm to about 5 cm (including the portion of the conduit disposed in the myocardium).
• FIG. 8 also illustrates a device for securing an end of the conduit to tissue located adjacent the source of blood. The device is indicated generally by thereference numeral90 and is shown in detail inFIGS. 9-11.FIG. 9 is an enlarged view of thedistal end22 of theconduit18 coupled to thedevice90 as shown inFIG. 8.FIG. 10 is an enlarged view of a fitting92 which forms part of thedevice90.FIG. 11 is an enlarged view of a tissue section T showing one preferred placement of thedevice90 so as to communicate with a source of blood S.
• The fitting92 preferably comprises a tubular member with opposite ends opening into a hollow interior. The fitting92 may be formed of any suitable material having sufficient strength to remain open against compressive forces exerted by the tissue. Suitable materials include stainless steel, titanium, tantalum, polymers, etc. The dimensions of the fitting92 may be varied depending on the particular application and the material(s) used. As an example, for use in the application illustrated inFIG. 8, the fitting92 may be formed from 6 or 8-gauge thin wall 304 stainless steel hypo tube stock with a length of approximately 23 mm and an OD of approximately 5 mm.
• The fitting92 may be provided with one ormore openings94 for securing theliner28 to the fitting or better fixing the position of the fitting in tissue. The fitting92 also may be provided with aflange96 at an end thereof for engaging tissue and further securing thedevice90 in position. As shown inFIG. 10, another end of the fitting92 is provided with one ormore grooves98 for use in securing theconduit18 to the fitting.FIG. 9 illustrates theconduit18 passed through the interior of the fitting92 with thedistal end22 of the conduit everted over the end of the fitting. In the illustrated embodiment, one or more lengths of suture extend around the everteddistal end22 of theconduit18 and lie in thegrooves98 so as to secure the conduit to the fitting92. It will be appreciated that the lengths of suture may be omitted or replaced by alternative fastening means, for example, biologically compatible adhesives, clips, bands, wire, etc.
• The preferred embodiment of the conduit also includes a component for preventing blockage of the end of the device that is placed in communication with the source of blood. The component includes sufficient structure to prevent blockage and at least one opening through which blood from the source may enter the conduit. As an example, when placing a conduit in communication with a heart chamber, such as the left ventricle, an end of the conduit is positioned in and extends through the myocardium. The conduit end will move relative to the myocardial tissue, and particularly the endocardium, which may result in tissue overlying all or a portion of the open end of the conduit. The end of the conduit that is in the ventricle will also be located near tissue such as the chordae tendineae, papillary muscle or other myocardial tissue, thereby increasing the risk of such tissue blocking blood flow into the conduit.
• One preferred component for preventing blockage of the conduit is indicated by thereference numeral100 inFIGS. 9 and 11 and is provided on thedevice90. Thecomponent100 is in the form of a structure comprising a plurality ofstruts102 definingopen areas104 through which blood may flow. Eachstrut102 has oneend106 secured to the fitting92 while the other ends of the struts meet at ajunction108. Thestruts102 may be formed of various materials, for example, stainless steel wire or any of the materials used to form the fitting, and theends106 may be secured to the fitting92 by any suitable means, e.g., brazing, welding, adhesives, etc. As an example, thestruts124 may be formed from304 full hard stainless steel wire with a length of approximately 18 mm and an outer diameter of approximately 0.375 mm. If constructed as in the illustrated embodiment, the length of the portion of eachstrut124 extending beyond theproximal end120 of thevessel112 may be approximately 8 mm.
• While the illustrated mechanism includes threecurved struts104, fewer or more struts may be used, and the struts may be straight, curved, or otherwise shaped, and may be rigid or flexible. Further, it will be readily appreciated that alternative mechanisms for preventing blockage of the end of the conduit that communicates with the heart chamber (or other blood source) may be used in lieu of that illustrated in the Figures. For example, rather than a plurality of individual struts, the mechanism could comprise a grid or mesh that allows blood to flow into the conduit.
• FIG. 11 schematically illustrates one possible orientation of thedevice90 in tissue wherein theflange96 engages an exterior surface of the tissue and aids in fixing the device in position. Theopenings94 may be provided in order to enhance fixation of thedevice90 in the tissue. For example, theopenings94 in theflange96 may receive suture (not shown) that secures the fitting to tissue. In addition, theopenings94 in theflange96 may be filled with a penetrable material, such as silicone, for holding various devices or instruments, e.g., needles, forceps, etc. For instance, a surgeon may use the material as a needle holder while performing a suturing procedure.
• Thecomponent100 is positioned so as to be partially disposed within the tissue T with a portion extending into the blood source S. Thedistal end22 of theconduit18 is positioned so as to extend slightly into the blood source S. The portion of thecomponent100 disposed in the blood source S acts as a barrier while allowing blood to enter theconduit18. For instance, the end of the conduit that is placed in the ventricle will be located near tissue such as the chordae tendineae, papillary muscle or myocardial tissue, thereby creating a risk of such tissue blocking the flow of blood into the conduit. Thestruts102 located in the blood source S will prevent (or minimize) obstruction of the distal end of theconduit18 by such tissue, it being appreciated that the length of the struts and the extent to which they extend into the blood source may vary from that shown. In addition, thecomponent100 will prevent or minimize tissue being forced into the fitting92 during placement of the fitting in the myocardium.
• The embodiment ofFIGS. 9-11 may rely on blood flow through theconduit18 to maintain theliner28 fully (or substantially fully) open within the interior of the fitting92. However, it may be desirable in some instances to positively secure theliner28 to the fitting92 so as to ensure that theconduit18 remains open under varying conditions, e.g., pressure differences occurring during the systolic and diastolic phases of the heart cycle.FIGS. 12 and 12A illustrate one embodiment in which theliner28 is positively secured to the fitting92, the means for securing theliner28 comprising alayer110 of silicone disposed along all or a portion of thedevice90.
• Thelayer100 of silicone fills the space between the exterior of theliner28 and the interior of the fitting92, the silicone acting as a biologically compatible adhesive that maintains the liner against the wall of the fitting. The silicone flows into theopenings94 in the fitting92 which enhances attachment of theliner28. In the illustrated embodiment theopenings94 have a flaredend112 opposite theliner28. The ends112 receive the silicone so that each opening94 forms a rivet-like plug of silicone that securely holds theliner28 to the fitting92. SeeFIG. 12A. Also, as shown in phantom inFIG. 12A, silicone (or another material) may be placed on the exterior of the rivet-like plug to provide a more secure connection.
• In addition, thedevice90 preferably includes anotherlayer114 of silicone disposed over the proximal end of the fitting92 as well as over a portion of thestruts102 of thecomponent100. Thelayer114 may be used to provide a smooth coating that covers the edges of thestruts102 and the fitting92 to avoid or minimize trauma to tissue.
• Thedevice90 may also be provided with means for preventing the conduit18 (and in particular the liner28) from collapsing during use. One suitable means is astrain relief element116 that surrounds theliner28, as shown inFIG. 12. Thestrain relief element116 may be a helical wire, such as stainless steel or nitinol, that is wrapped around theliner28. The strain relief element may extend over all or a portion of the length of the conduit. If a layer of silicone is used as in the illustrated embodiment, theelement116 may be bonded to or embedded in the silicone.
• Other means for preventing theliner28 from collapsing include placing an internal support member in the liner, such as a stent (as shown inFIG. 6A), that maintains the conduit open. Alternatively, the conduit, e.g., theliner28, may be constructed in a preformed shape that will resist kinking or collapsing; for example, the conduit may be coated with a material that provides a desired amount of rigidity, such as silicone, polyurethane, PTFE, or other polymers. The coating is preferably on the exterior of theliner28 to maintain the ePTFE-blood interface. Theliner28 may be provided with additional coatings selected to provide particular qualities, such as heparin coatings. As another alternative, which may be used in addition to or in lieu of providing the conduit with a strain relief element to prevent kinking, the portion of the conduit extending through the myocardium, such as the fitting92 inFIGS. 8-12, could be specifically formed to prevent kinking. For instance, the fitting92 could be L-shaped with a bend to prevent kinking at the junction of the fitting and the remainder of the conduit, the conduit including straight or tapered walls. Other configurations may of course be used as well.
• FIG. 13 is a perspective view of another embodiment of the invention comprising a device (which may have the same construction as thedevice10 shown inFIG. 1) provided with aconduit118 specifically configured to be placed in communication with a heart chamber. Theconduit118 is loaded on theshaft assembly14 and has a distal end constructed as described above and a proximal end provided with thedevice90 shown inFIG. 9. Thedevice90 is adapted to be placed in fluid communication with a source of blood such as the left ventricle. The fitting92 is placed in the tissue of the myocardium so that thecomponent100 and the distal end of the fitting92 project slightly into the heart chamber, as shown inFIG. 11.
• FIG. 14 is a perspective view of still another embodiment of the invention comprising a device (which also may have the same construction as thedevice10 shown inFIG. 1) provided with aconduit120. Theconduit120 is loaded on theshaft assembly14 and preferably has a distal end constructed as in the previous embodiments. Theconduit120 also has a proximal end including a device90 (and component100) that is adapted to be placed in fluid communication with a heart chamber and is preferably constructed as in the previous embodiments. It should be understood, though, that this embodiment may be practiced with a conduit that is adapted to be placed in communication with another blood source, such as the aorta.
• This embodiment of the invention allows a conduit to be placed in fluid communication first with a source of blood and then with a target vessel, or vice-versa. Placing the conduit in communication with the blood source first may be useful to de-air the conduit, i.e., force air from the conduit interior, prior to securing the conduit to the target vessel.FIG. 14 shows one construction wherein theconduit120 has anopening122 through which the a portion of theshaft assembly14 passes. The proximal end of theconduit120 including thedevice90 may be positioned in the myocardial tissue, for example, through an incision made in the myocardium. The positive pressure in the heart chamber (especially the high pressures present in the left ventricle during systole) forces air through theconduit120 and out the distal end adjacent thesheath42. Theopening122 may be substantially sealed against theshaft assembly14 of the device to force air toward the distal end of theconduit120.
• The embodiment exemplified inFIG. 14 permits either end of theconduit120 to be placed first, which may be used to de-air the conduit as described above. This feature of the invention also provides flexibility so that in a given procedure the user has the option to first secure the conduit to either the blood source or the target vessel, which may be beneficial, for example, in a multi-vessel bypass procedure where access to different areas of the heart is obtained by temporarily moving or retracting all or a portion of the heart.
• Theopening122 in theconduit120 is preferably formed to allow its closure during the procedure. For instance, theconduit120 could be clamped proximal to theopening122 after the proximal end of the conduit has been placed in communication with the blood source and the conduit de-aired. The distal end of theconduit120 could then be deployed in the target vessel and the shaft assembly removed through theopening122. Air would be forced out of the conduit and theopening122 then sealed by a patch formed of tissue or synthetic vascular graft material such as ePTFE. The patch (not shown) could by fixed to the conduit by various means, e.g., suture, clips, biologically compatible adhesives, etc. Alternatively, theconduit120 could include a collapsible, foldable or crimpable member which is sealed closed after theshaft assembly14 has been removed from the conduit. It will be recognized that an opening into the conduit could be formed at any location along the length of the conduit and in any component forming part of the conduit, for example, in the fitting92 ofdevice90.
• Theillustrated conduit120 also is provided with means for preventing the conduit from collapsing or kinking. Theproximal end122 of the conduit (or more of the conduit, if desired) is provided with aninternal support124 to maintain the lumen of theconduit120 open. Thesupport124 may be in the form of a self-expanding stent formed of a suitable material such as nitinol, titanium or tantalum. Thesupport124 preferably includes an articulatedportion126 that supports a curved section of the conduit120 (and in particular the liner128). The conduit is preferably rigid enough to remain open while being somewhat flexible. The conduit may be preformed to assume a desired orientation that provides an optimum blood flow path or achieves particular flow characteristics. Also, while thesupport124 is shown disposed within theconduit120 it may instead surround the exterior of the conduit.
• The device of the invention may be sized and configured differently from that specifically illustrated in the Figures. As an example of a range of possible constructions, the device may be relatively short with the shaft assembly substantially rigid for use in an open-chest procedure. The device may be configured for use in either a minimally invasive or endosvascular procedure, wherein the actuators for controlling the device components are located adjacent the proximal end of the device to allow remote deployment of the conduit.
• FIG. 15 is a perspective view of such a device constructed according to another embodiment of the invention. Thedevice130 is designed for use in a minimally invasive (e.g., laparoscopic, thoracoscopic or endoscopic) procedure. Thedevice130 has a similar construction to thedevice10 described above and includes ahandle132, ashaft assembly134 and anactuator assembly136. Theshaft assembly134 supports aconduit138 having aproximal end140 and adistal end142. Atubular access device144 may be provided so as to be moveable over theshaft assembly134 and is adapted to be passed through an opening in the patient's body. For example, the opening could be a thoracotomy passing through the chest wall for performing a thoracoscopic procedure (as shown inFIG. 16), or it could be laparotomy passing into the abdominal cavity to allow the chest cavity to be accessed through the diaphragm. Thedevice144 may have a flange or other portion to grip and manipulate the device with respect to theconduit138 during use.
• Theconduit138 is similar to theconduit18 shown inFIG. 13 and comprises a vessel coupling in the form of astent146 coupled to aliner148. Asheath150 is disposed over thedistal end148 of theconduit138 and holds the end in a collapsed orientation as explained above with respect to previous embodiments. Theshaft assembly134 preferably includes a sheath removal mechanism thebody152 of which is visible inFIG. 15. Theactuator assembly136 includes afirst actuator154 for controlling the sheath removal mechanism (which operates as described above), and asecond actuator156 for controlling the position of thesheath150 with respect to theconduit138. As in the previous embodiment, theactuators154,156 are preferably arranged to permit theconduit138 to be deployed in the target vessel via a one-handed operation, with theactuator156 moving thesheath150 to deploy the conduit and theactuator154 removing thesheath150 from theconduit138.
• FIG. 16 shows schematically one possible application for thedevice130 wherein a port P has been formed between a patient's ribs to access the chest cavity and the heart (not shown). A trocar sleeve or likestructure158 may be used to form the port P and one or more retractors (not shown) may be used as well. Thedevice130 is shown positioned through thetrocar sleeve158 with a distal portion of theshaft assembly134 including theconduit138 extending into the chest cavity. The actuator assembly is preferably located at or near the proximal end of thedevice130 which allows easy actuation to deploy theconduit138 in the target vessel. Additional ports P may be provided to introduce additional instruments into the chest cavity. For example, thedevice130 could be used to deploy theconduit138 in the target vessel, thedevice130 removed, and one or more instruments passed through other ports to place the conduit in communication with a source of blood such as the aorta, a coronary vessel, or a heart chamber containing blood. Alternatively, the conduit could be placed in communication with the blood source prior to the target vessel.
• The conduit may be placed in communication with the target vessel in any of several manners according to the invention. In the embodiment shown inFIGS. 6 and 6A, the lumen of the target vessel may be partially or completely occluded by the conduit (and in particular the liner) once the conduit section has expanded to its final position. As a result, native blood flow from a proximal source may be hindered or prevented from moving distally past the attachment site between the conduit and the target vessel. In the case of a coronary artery, the conduit could limit or block native blood flow through the artery, i.e., blood flowing through the artery from a proximal source, e.g., the aorta. Many patients undergoing a CABG procedure will have some native blood flow in one or more obstructed arteries. It therefore would be desirable to place a conduit in fluid communication with the target vessel in a manner that preserves such native blood flow in the target vessel.
• According to another embodiment of the invention a conduit is placed in fluid communication with a target vessel while preserving native blood flow through the target vessel. That is, blood flowing through the target vessel prior to placing the conduit is free to flow past the site of the attachment. One way of achieving this is by constructing the conduit to include a portion that is placed in the target vessel and allows flow past the attachment site. Another way to preserve native flow is by forming an opening in a solid wall of a conduit placed in the target vessel lumen.
• FIG. 17 shows aconduit160 constructed in a manner that preserves native blood flow in the target vessel. Theconduit160 comprises astent162 coupled to aliner164 in a manner described above with respect to previous embodiments. Thestent162 includes aframe portion166 with one ormore members168 that engage the wall of the target vessel TV to secures theconduit160 to the vessel. Theliner164 preferably surrounds (either partially or completely) theframe portion166 but does not obstruct the lumen of the target vessel TV. Theconduit160, and in particular thestent162 andframe portion166, may be constructed and deployed in a target vessel according to the teachings in the aforementioned application Ser. No. 09/232,103, filed on Jan. 15, 1999 and entitled “Methods and Devices for Forming Vascular Anastomoses,” the entire subject matter of which has been incorporated herein by reference.
• An alternative conduit embodiment that preserves native flow through the target vessel is designated byreference numeral170 inFIG. 18 and comprises astent172 coupled to aliner174, preferably in the manner described above with respect to previous embodiments. Thestent172 includes aframe portion176 that includes a pair offrame members178 which engage the wall of the target vessel TV to secure theconduit170 to the vessel. Theliner174 preferably surrounds theframe portion176 as described in connection withFIG. 17; however, for sake of clarity, theliner174 is shown terminating at the junction of theconduit170 and the target vessel TV.
• FIG. 19 is a flat pattern (two-dimensional) illustration of atube180 that has been cut to form thestent172 ofFIG. 18. The tube is cut to form first andsecond sections182,184 corresponding to therespective frame members178. Thesections182,184 have a diamond-pattern construction and are joined to thebody186 by at least one, and preferably multiple attachment points188.FIG. 19 shows thestent172 in an expanded form but with theframe portions176 disposed along a first axis which, in the illustrated embodiment, corresponds to the longitudinal axis of thestent body186. Theframe members178 preferably move to the position shown inFIG. 18 in which they are disposed along a second axis which is generally transverse to the first axis. In the illustrated embodiment, the second axis is substantially perpendicular to the first axis, although other configurations may be used. Upon deployment of theconduit170 in the target vessel theframe members178 preferably move along a curved path from the first axis to the second axis.
• Another alternative conduit embodiment that preserves native flow through the target vessel is designated byreference numeral190 inFIG. 20 and comprises astent192 coupled to aliner194. Thestent192 andliner194 may be coupled in the manner described above. Thestent192 includes aframe portion196 which includes a pair offrame members198 for engaging the wall of the target vessel TV, thereby securing theconduit190 to the vessel as shown inFIG. 20. As in the embodiment ofFIG. 18, theliner194 preferably surrounds theframe portion176 but, for sake of clarity, is shown ending at the junction of theconduit170 and the target vessel TV.
• FIG. 20 is a flat pattern (two-dimensional) illustration of atube200 that has been cut to form thestent192 shown inFIG. 19. The tube is cut to form first andsecond sections202,204 corresponding to therespective frame members198 which, in the illustrated embodiment, have a zigzag configuration. Thesections202 and204 are joined to thestent body206 by at least one, and preferably multiple attachment struts208.FIG. 21 is similar toFIG. 19 in that it shows thestent192 in an expanded form but withframe sections198 disposed along the longitudinal axis of thestent body186 instead of transverse to the body, which is the position theframe members178 move to upon deployment of theconduit190 in a target vessel.
• The conduits depicted inFIGS. 17-21, and in particular the stents that form the vessel couplings of such conduits, may have various configurations and may be formed according to the process described above with respect to previous embodiments. That is, thestents162,172 and192 may be cut or formed from a suitable material subjected to a procedure such as laser cutting, EDM (electrical discharge machining), photochemical etching, etc. The cut stent may be further processed or finished to remove burrs or surface irregularities, for example, by acid etching, electropolishing, or abrasive blasting. Next, the frame sections that engage the wall of the target vessel are shape-set to their expanded orientation. This may be done by placing the frame sections in that orientation and applying sufficient heat to produce a structure that will assume the desired configuration above a certain temperature, e.g., 5° below body temperature. The stent may then be placed in its collapsed orientation by cooling (e.g., with liquid nitrogen), coupled to a liner and loaded onto a delivery device, and then deployed in a target vessel.
• The embodiments of the invention shown inFIGS. 17,18 and20 preserve native blood flow through the target vessel and have a construction that does not cover a major portion of the inner or posterior wall of the target vessel. As shown, the frame structure that is placed in the target vessel contacts the inner wall of the vessel to secure the conduit but leaves the majority of the vessel wall uncovered. This allows blood flowing through the target vessel to feed septal perforators (not shown but extending downward as viewed inFIG. 17) so as to perfuse the myocardial tissue. This feature thus prevents the myocardial tissue perfused by the septal perforators from becoming ischemic due to the conduit located in the target vessel. It should be appreciated that while it is preferred to leave the majority of the vessel wall unexposed to perfuse as many septal perforators as possible, the invention may be practiced with a conduit that covers more or less of the vessel wall than that shown.
• The illustrated devices utilize a self-expanding stent and, as such, the device is not provided with an expansion mechanism for deploying the stent. It will be recognized, however, that either a self-expanding stent or a stent expanded by suitable means, e.g., a balloon or a non-inflatable expansion mechanism, may be used. For example, the device may be constructed the same as or similar to the device disclosed in application Ser. No. 09/232,102, filed on Jan. 15, 1999, and entitled “Methods and Devices for Forming Vascular Anastomoses,” the entire subject matter of which has been incorporated herein by reference. The device could be provided with a separate inflation lumen for inflating the balloon to expand the stent, or the design in the aforementioned application may be used with seals such as O-rings or the like.
• The invention also may use a conduit provided with a valve or other means for controlling or regulating blood flow. A valve could take the form, for example, of any of the valves disclosed in application Ser. No. 09/023,492, filed on Feb. 13, 1998, and entitled “Methods and Devices Providing Transmyocardial Blood Flow to the Arterial Vascular System of the Heart,” the entire subject matter of which has been incorporated herein by reference.
• Similarly, it will be appreciated that a conduit or vessel coupling configured to preserve native blood flow in a target vessel may be constructed differently than that shown inFIGS. 17-21. For example, the portion of the vessel coupling that is disposed in the target vessel could take the form of a single section of a coronary stent joined to the main body of the stent. Further, if desired the portion of the vessel coupling that permits native flow through the target vessel could control or meter the flow. Other variations may be used as well.
• It will be appreciated that the features of the various preferred embodiments described herein may be used together or separately, while the illustrated methods and devices may be modified or combined in whole or in part. As an example, the attachment formed between the conduit and the target vessel may be suture-free while allowing or blocking native flow through the target vessel; alternatively, the attachment may be formed to allow native flow through the target vessel but be created using, in whole or in part, conventional suturing techniques.
• It should be appreciated that a device constructed according to the invention could be operated with one or two hands (and by one or more users), although a one-hand operable embodiment is specifically illustrated. Also, the device of the invention may include removable or detachable components, or could be constructed as a one-piece instrument with no separable components. The device may be formed as a disposable instrument, a reusable instrument capable of being sterilized, or a combination of disposable and reusable components.
• Further, it will be understood that the embodiments may be used in various types of procedures, for example, an open surgical procedure including a median sternotomy, a minimally invasive procedure utilizing one or more relatively small access openings or ports, or an endovascular procedure using peripheral access sites. Also, endoscopes or thoracoscopes may be used for visualization if the procedure is performed through very small ports. The different embodiments may be used in beating heart procedures, stopped-heart procedures utilizing cardiopulmonary bypass (CPB), or procedures during which the heart is intermittently stopped and started. Finally, any suitable delivery device, instrument or catheter may be used in conjunction with the invention.
• It also will be recognized that the invention is not limited to the illustrated applications, namely, placing a coronary vessel in fluid communication with a source of blood. For example, the invention may find application in treating peripheral arterial disease in the distal abdominal aorta including the infrarenal aorta and aortoiliac segment, aortofemoral, or carotid, and to treat disease in the iliac and renal artery lesions.
• The preferred embodiments of the invention are described above in detail for the purpose of setting forth a complete disclosure and for sake of explanation and clarity. It will be readily understood that the scope of the invention defined by the appended claims will encompass numerous changes and modifications.

Claims (36)

1-59. (canceled)

60. A method for performing bypass on a vessel by placing the vessel in fluid communication with a heart chamber containing blood, the method comprising steps of:

(a) providing a first vessel having a lumen, the first vessel being sized and configured for being joined to a second vessel having a lumen that is at least partially obstructed;

(b) placing at least a portion of the first vessel adjacent the lumen of the second vessel downstream of the obstruction so as to place the lumens of the first and second vessels in fluid communication;

(c) fixing the first vessel in position with respect to the lumen of the second vessel without using suture to form a substantially suture-free anastomosis between the first and second vessels; and;

(d) placing the first vessel in fluid communication with a heart chamber containing blood so as to deliver blood from the heart chamber to the lumen of the second vessel.

61. The method ofclaim 60, further comprising a vessel coupling secured to the first vessel and configured to be anastomosed to the second vessel without suture.

62. The method ofclaim 61, wherein the vessel coupling is an expandable conduit that is placed at least partially into the lumen of the second vessel and expanded to engage the second vessel and form the anastomosis.

63. The method ofclaim 62, wherein the expandable conduit is a stent secured to the first vessel by suture and step (c) is carried out without using any suture.

64. The method ofclaim 63, wherein the first vessel comprises a combination of autologous tissue and synthetic graft material adapted to be anastomosed to a coronary artery.

65. The method ofclaim 64, wherein the heart chamber is the left ventricle.

66. The method ofclaim 65, wherein the first vessel communicates with the left ventricle via a flow path passing through the myocardium.

67. The method ofclaim 65, wherein the anastomosis is formed to permit native blood flow through the coronary artery to flow past the site of anastomosis.

68. A method for bypassing an obstruction in a coronary artery by placing the coronary artery in fluid communication with a heart chamber containing blood, the method comprising steps of:

(a) providing a stent-graft assembly including a stent movable between expanded and non-expanded orientations and a graft vessel attached to the stent, wherein the graft vessel has a lumen in fluid communication with the stent;

(b) forming an opening in the wall of the coronary artery that is sized to allow at least a portion of the stent to be positioned in the lumen of the coronary artery when the stent is in the non-expanded orientation;

(c) positioning at least a portion of the stent in the lumen of the coronary artery and expanding the stent into contact with the coronary artery to form a substantially suture-free anastomosis between the graft vessel and the coronary artery; and

(d) placing the graft vessel in communication with a heart chamber containing blood.

69. The method ofclaim 68, wherein the stent is loaded on a balloon in the non-expanded orientation and the balloon is expanded during step (c).

70. The method ofclaim 68, wherein the stent-graft assembly is secured to the coronary artery without completely occluding the lumen of the coronary artery so as to allow blood flowing in the coronary artery to flow past the site of the anastomosis.

71. A device for forming an anastomosis between a graft vessel and a target vessel during a bypass procedure in which the target vessel is placed in fluid communication with a heart chamber containing blood, the device comprising:

a vessel coupling configured to secure a graft vessel to a target vessel, the vessel coupling having a lumen and being movable between expanded and non-expanded orientations;

a graft vessel secured to the vessel coupling with the lumens of the graft vessel and the vessel coupling in fluid communication, a portion of the graft vessel being adapted to be placed in fluid communication with a heart chamber containing blood;

wherein the vessel coupling is sized and configured to fit at least partially within the lumen of a coronary artery in said non-expanded orientation and to engage the coronary artery in said expanded orientation.

72. The device ofclaim 71, further comprising a support member supporting the vessel coupling and the graft vessel, the support member adapted to be at least partially placed in the lumen of the target vessel.

73. The device ofclaim 72, wherein the expansion mechanism comprises a balloon carried by the support member, and further comprising means for coupling the balloon to a source of pressurized fluid for expanding the vessel coupling to the expanded orientation.

74. The device ofclaim 73, wherein the vessel coupling is a stent and the graft vessel comprises a combination of autologous tissue and synthetic graft material.

75. The device ofclaim 74, further comprising a sheath overlying the vessel coupling and the graft vessel, the sheath comprising a peel-away sheath that is torn and removed to selectively expose the vessel coupling and the graft vessel.

76. The device ofclaim 71, wherein the vessel coupling is configured with a plurality of open areas to permit blood flowing through the target vessel to flow past the vessel coupling after forming the anastomosis.

77. A device for performing a bypass procedure in which a suture-free anastomosis is formed between a graft vessel and a coronary artery, and wherein the graft vessel is placed in communication with a heart chamber containing blood to deliver blood from the heart chamber to the coronary artery, the device comprising:

a stent-graft assembly including a stent movable between collapsed and expanded orientations and a graft vessel having a lumen, wherein the stent is secured to the graft vessel with the lumen of the graft vessel is in fluid communication with the stent; and

an expansion mechanism for expanding the stent to the expanded orientation once the stent has been at least partially positioned in the lumen of a coronary artery;

wherein the stent and graft vessel are sized and configured to be collapsed for placement in the lumen of the coronary artery and then expanded to cause the stent to engage the wall of the coronary artery to anasotmose the stent-graft assembly to the coronary artery without suture.

78. The device ofclaim 77, wherein the stent-graft assembly is configured to permit blood flowing through the coronary artery from the aorta to move past the site of the anastomosis.

79. A method for placing a target vessel in fluid communication with a heart chamber containing blood while preserving native blood flow through the target vessel, the method comprising steps of:

(a) providing a graft vessel selected from the group consisting of tissue grafts, synthetic grafts, and grafts formed of both tissue and synthetic material, wherein the graft vessel has a lumen and is adapted to be secured to a target vessel having a lumen;

(b) fixing at least a portion of the graft vessel to the target vessel without using suture to form a substantially suture-free anastomosis between the graft and target vessels that is distal to the obstruction in the target vessel;

(c) placing the graft vessel in fluid communication with a heart chamber containing blood; and

(d) allowing any native blood flow in the target vessel to move past the site of the anastomosis.

80. The method ofclaim 79, further comprising securing a vessel coupling to the graft vessel and anastomosing the vessel coupling to the second vessel without using suture.

81. The method ofclaim 80, wherein the graft vessel comprises a synthetic portion in communication with the target vessel and a tissue portion in communication with the heart chamber.

82. The method ofclaim 80, wherein the tissue portion of the graft vessel comprises a section of saphenous vein while the synthetic portion of the graft vessel comprises a section of ePTFE.

83. The method ofclaim 79, wherein the vessel coupling comprises an expandable conduit disposed over an expansion mechanism, and step (b) is carried out by expanding the expansion mechanism to force the expandable conduit against the target vessel.

84. The method ofclaim 79, wherein the vessel coupling comprises a frame configured to be retained within the lumen of the target vessel while not blocking blood flow in the target vessel, and the frame is collapsed for insertion into the target vessel and then expanded against the wall of the target vessel.

85. The method ofclaim 79, wherein step (b) is carried out without suturing the graft vessel to the target vessel.

86. The method ofclaim 79, further comprising coupling an end of the graft vessel to a tubular element adapted to communicate with the heart chamber, and fixing the tubular element to the myocardium so as to extend into the heart chamber and place the graft vessel in fluid communication with the heart chamber.

87. A device for performing a bypass procedure in which a target vessel is place din communication with a heart chamber containing blood and an anastomosis is formed between a graft vessel and the target vessel that allows native blood flow through the target vessel, the device comprising:

a graft vessel adapted to be anastomosed to a target vessel and placed in communication with a heart chamber containing blood;

a vessel coupling secured to the graft vessel, wherein the vessel coupling has a lumen and is configured to be anastomosed to the target vessel to place the graft and target vessels in fluid communication; and

wherein the vessel coupling is secured to the graft vessel so as to allow blood flow through the target vessel to move past the site of the anastomosis.

88. The device ofclaim 87, wherein the vessel coupling comprises a first portion secured to the graft vessel and a second portion sized and configured to engage the interior of the wall of the target vessel to fix the vessel coupling in place.

89. The device ofclaim 88, wherein the first portion of the vessel coupling comprises a stent and the second portion of the vessel coupling comprises a plurality of coils that engage the lumen of the target vessel.

90. The device ofclaim 87, further comprising a support member supporting the vessel coupling and the graft vessel, wherein the support member is adapted to be at least partially placed in the lumen of the target vessel.

91. The device ofclaim 87, further comprising a removable sheath overlying the vessel coupling and the graft vessel.

92. The device ofclaim 87, wherein the vessel coupling is configured to be fixed to the target vessel without suture to form a suture-free anastomosis.

93. A device for use in performing a bypass procedure in which a first vessel is placed in fluid communication with a heart chamber containing blood and anastomosed to a second vessel with a lumen containing an obstruction, the device comprising:

a vessel coupling including first and second portions for forming an anastomosis between a first vessel and a second vessel;

wherein the first portion of the vessel coupling is configured to be coupled to a first vessel that is in fluid communication with a heart chamber containing blood so that blood flows from the heart chamber and through the coupling; and

wherein the second portion of the vessel coupling is configured to be secured to a second vessel without using suture to form a substantially suture-free anastomosis that allows native blood flow through the second vessel to move past the site of the anastomosis.

94. The device ofclaim 93, wherein at least the second portion of the vessel coupling is formed of a shape memory allow and is collapsed for introduction into the second vessel and then expanded to engage the wall of the second vessel to form the anastomosis.

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