Intravascular arterial to venous anastomosis and tissue welding catheter
Systems and methods for creating an arteriovenous (AV) fistula comprise an elongate member, a distal member connected to the elongate member and movable relative to the elongate member, and a heating member disposed on at least one of the movable distal member and the elongate member. The distal member comprises structure for capturing tissue to be cut to create the fistula, and the heating member is adapted to cut through the tissue to create the fistula. The elongate member comprises an elongate outer tube. A shaft connects the distal member to the elongate member, and is extendable and retractable to extend and retract the distal member relative to the elongate member.
1. A method of creating a desired AV fistula between adjacent first and second vessels, comprising:
inserting a guidewire from the first vessel into the second vessel;
inserting a catheter comprising a proximal elongate member and a distal member over the guidewire, so that a tapered distal tip of the distal member comes into contact with a selected anastomosis site, each of the proximal elongate member and the distal member having a fixed outer configuration;
advancing the distal member entirely into the second vessel, while the proximal elongate member remains entirely in the first vessel, thereby enlarging an aperture between the first and second vessels;
retracting the distal member toward the proximal elongate member to clamp tissue surrounding the aperture between opposed facing surfaces on each of the distal member and the proximal elongate member, the opposed facing surfaces on each of the distal member and the proximal elongate member comprising a distal blunt rigid surface on the proximal elongate member and a proximal blunt rigid surface on the distal member, wherein the tissue is clamped while contacting each of the distal blunt rigid surface on the proximal elongate member and the proximal blunt rigid surface on the distal member; and
applying energy to a heating member on one of the distal member and the proximal elongate member to further cut and enlarge the aperture, and to weld an edge thereof in order to create the desired AV fistula between the first and second vessels.
2. The method as recited in claim 1 , wherein the opposed facing surfaces are each tapered and aligned to one another, the heating member being disposed on at least one of the two aligned blunt facing rigid tapered surfaces.
3. The method as recited in claim 2 , and further comprising a step of capturing the cut tissue within a cavity disposed adjacent to the heating member.
4. The method as recited in claim 2 , and further comprising dispersing heat away from the heating member using a heat spreader comprising a conductive material disposed on the blunt facing rigid tapered surface beneath the heating member.
5. The method as recited in claim 1 , wherein the advancing step comprises moving the distal member distally relative to the proximal elongate member so that the distal member is spaced a greater axial distance from the proximal elongate member after the advancing step is performed than it is before the advancing step is performed.
6. The method as recited in claim 5 , wherein the retracting step comprises moving the distal member proximally relative to the proximal elongate member so that the distal member is spaced a lesser axial distance from the proximal elongate member after the retracting step is performed than it is before the retracting step is performed.
7. The method as recited in claim 5 , wherein the catheter is rotated during the advancing step.
8. The method as recited in claim 6 , wherein the advancing step is performed by advancing a central tubular structure distally from an outer tube comprising the proximal elongate member, and the retracting step is performed by withdrawing the central tubular structure proximally into the outer tube.
9. The method as recited in claim 8 , wherein the heating member is disposed on the distal member and further wherein the retracting step includes a step of applying a slight tension to the heating member on the distal member to seat the heating member against a wall of the second vessel.
10. The method as recited in claim 9 , and further comprising a step of advancing the outer tube after the retracting step, until a distal end of the outer tube contacts a wall of the first vessel, thereby clamping the tissue surrounding the aperture between the opposed facing surfaces on each of the distal member and the proximal elongate member.
11. The method as recited in claim 1 , wherein the applying energy step comprises a tissue cutting step followed by a tissue welding step, the tissue welding step being managed to cauterize and weld the edge of the aperture formed during the tissue cutting step.
12. The method as recited in claim 1 , and further comprising a step of creating said aperture by using a needle to puncture a wall of the first vessel and an adjacent wall of the second vessel, prior to the step of inserting the guidewire.
13. The method as recited in claim 1 , wherein the inserting step comprises inserting only the catheter over the guidewire.
14. A method of creating, a desired AV fistula between adjacent first and second vessels, comprising:
inserting a guidewire from the first vessel into the second vessel;
inserting a catheter comprising a proximal elongate member formed of a rigid material and a distal member over the guidewire, so that a tapered distal tip of the distal member comes into contact with a selected anastomosis site;
advancing the distal member entirely into the second vessel, until a rigid distal face of the proximal elongate member contacts a tissue wall of the first vessel, so that the proximal elongate member remains entirely in the first vessel, thereby enlarging an aperture between the first and second vessels;
retracting the distal member toward the proximal elongate member, until a rigid proximal face of the distal member contacts a tissue wall of the second vessel; and
applying energy to a heating member on one of the distal member and the proximal elongate member after the retracting step to further cut and form the aperture, and to weld an edge thereof in order to create the desired fistula between the first and second vessels.
15. The method as recited in claim 14 , wherein the rigid distal face of the proximal elongate member and the rigid proximal face of the distal member comprise aligned blunt facing tapered surfaces, between which the tissue surrounding the aperture is clamped, wherein the heating member is disposed on one of the distal and proximal aligned blunt facing tapered surfaces.
16. The method as recited in claim 15 , and further comprising dispersing heat away from the heating member using a heat spreader comprising a conductive material disposed on the one of the distal and proximal aligned blunt facing tapered surfaces beneath the heating member.
17. The method as recited in claim 14 , wherein the advancing step comprises moving the distal member distally relative to the proximal elongate member so that the distal member is spaced a greater axial distance from the proximal elongate member after the advancing step is performed than it is before the advancing step is performed.
18. The method as recited in claim 17 , wherein the retracting step comprises moving the distal member proximally relative to the proximal elongate member so that the distal member is spaced a lesser axial distance from the proximal elongate member after the retracting step is performed than it is before the retracting step is performed.
19. The method as recited in claim 18 , wherein the advancing step is performed by advancing a central tubular structure distally from an outer tube comprising the proximal elongate member, and the retracting step is performed by withdrawing the central tubular structure proximally into the outer tube.
20. The method as recited in claim 14 , wherein the energy applying step comprises a tissue cutting step followed by a tissue welding step, the tissue welding step being managed to cauterize and weld the edges of the aperture formed during the tissue cutting step.
21. The method as recited in claim 14 , wherein the inserting step comprises inserting only the catheter over the guidewire.