Devices, systems and methods for creation of a peripherally located fistula

1. A method for percutaneously creating a fistula between a patient's artery and vein, said method comprising:

providing an assembly comprising a sheath having lumen therethrough, a needle removably received in the sheath, and a clip disposed within the sheath wherein the needle has a needle tip configured to be advanced through tissue;

percutaneously advancing the assembly through a skin layer of the patient and between a lumen of the artery and a lumen of the vein so that the needle is positioned through the artery and the vein and the clip of the assembly is positioned adjacent or between the lumens of the artery and the vein;

advancing a guidewire through a lumen of the needle and outwardly from the needle tip;

retracting the needle proximally over the guidewire while the sheath and the clip of the assembly remain in place; and

deploying the clip over the guidewire to scaffold the fistula between the artery and the vein.

2. A method as in claim 1 , wherein the artery is located above the vein in relation to the skin surface.

3. A method as in claim 1 , further comprising determining the fistula location prior to advancing the assembly through the skin layer.

4. A method as in claim 3 , wherein determining the fistula location comprises one or more visualization techniques selected from angiography, venography, extra-vascular ultrasound, intravascular ultrasound, and MRI.

5. A method as in claim 3 , wherein determining the fistula location comprises Doppler ultrasound.

6. A method as in claim 1 , wherein the assembly is inserted at an angle in the range from 20° to 80° relative to an external surface of the skin layer.

7. A method as in claim 1 , wherein the assembly is inserted at an angle approximately 90° relative to an external surface of the skin layer.

8. A method as in claim 1 , wherein the artery and the vein are peripheral.

9. A method as in claim 1 , wherein percutaneously advancing the assembly comprises advancing the needle tip through the skin layer, through the artery and into the vein so that the needle tip is in a lumen of the vein.

10. A method as in claim 9 , wherein the guidewire is advanced into the venous lumen prior to retracting the needle.

11. A method as in claim 10 , wherein deploying the clip comprises partially advancing the clip from a distal end of the sheath to release one or more tensioning arms on the clip.

12. A method as in claim 11 , further comprising retracting the sheath to contact the tensioning arm(s) against the venous wall prior to fully deploying the clip.

13. A method as in claim 12 wherein fully deploying the clip engages two tensioning arms against the venous wall and two tensioning arms against an arterial wall.

14. A method as in claim 1 , wherein the fistula has an oval cross-section.

15. A method as in claim 14 , wherein the oval has a major axis which is at least 20% greater than a minor axis.

16. A method as in claim 15 , wherein a length of the major axis is larger than a diameter of the vein or artery.

17. A method as in claim 1 , further comprising introducing a catheter over the guidewire after the clip has been deployed.

18. A method as in claim 17 , wherein the catheter is introduced to perform at least one of visualize the fistula, measure fistula flow, or modify the fistula.

19. A method as in claim 1 , further comprising selecting a patient suffering from at least one of chronic obstructive pulmonary disease, congestive heart failure, hypertension, hypotension, respiratory failure, pulmonary arterial hypertension, lung fibrosis and adult respiratory distress syndrome.

20. A method as in claim 1 , wherein deploying the clip comprises retracting the sheath of the assembly to free the clip from constraint such that the clip self-expands.