Systems and Methods for Percutaneous Access, Formation, and Maintenance of Arteriovenous Fistulas

Abstract

Methods for creating and maintaining an anastomosis between two adjacent blood vessels using percutaneous techniques, for use in hemodialysis procedures are disclosed and described.

What is claimed is: 
     
         1 . A method for creating an anastomosis between first and second blood vessels, comprising:
 identifying a procedural site for creating the anastomosis, having adjacent first and second blood vessels;   creating an opening at the procedural site through a first blood vessel wall and an adjacent second blood vessel wall;   advancing a catheter having a proximal portion and a distal portion over a guidewire to the procedural site;   advancing the distal catheter portion through the opening into the second blood vessel;   retracting the distal portion so that a proximal face thereon contacts tissue on the second blood vessel wall;   contacting tissue on the first blood vessel wall with a distal face on the proximal portion, thereby capturing tissue between the proximal and distal faces;   measuring a distance between the proximal and distal faces to thereby determine a thickness of the tissue captured between the proximal and distal faces;   releasing and recapturing the tissue if the determined thickness of the captured tissue is not within a predetermined range;   applying energy to a heating surface on one of the proximal and distal faces to heat the captured tissue to a prescribed temperature; and   stopping the application of energy to the heating surface when a measured distance between the distal and proximal faces reaches a desired level.   
     
     
         2 . The method as recited in  claim 1 , wherein the predetermined range of the thickness of the captured tissue is 0.1 mm-0.6 mm. 
     
     
         3 . The method as recited in  claim 1 , wherein the desired level is reached when the distal and proximal faces are in contact with one another. 
     
     
         4 . The method as recited in  claim 1 , and further comprising a step of advancing a sheath having a dilator to the procedural site over a guidewire prior to the catheter advancing step, the sheath advancing step comprising rotating the sheath as it is advanced over the guidewire to release any tissue that may be caught between the guidewire and the sheath or guidewire. 
     
     
         5 . The method as recited in  claim 4 , and further advancing the dilator through the opening to dilate the opening. 
     
     
         6 . The method as recited in  claim 1 , wherein the applying energy step includes applying short pulses of direct current energy to the heating surface. 
     
     
         7 . The method as recited in  claim 6 , wherein the applied heating pulses range from 0.5 to 3 seconds in length. 
     
     
         8 . The method as recited in  claim 1 , wherein the prescribed temperature is within a range of approximately 200 to 700 degrees F. 
     
     
         9 . The method as recited in  claim 1 , wherein, after the stopping step, a further pulse of energy is applied to heat tissue surrounding the catheter and thereby release any tissue sticking to the catheter so that the catheter may be withdrawn.