Stent to assist in arteriovenous fistula formation

Abstract

There is described an arteriovenous fistula stent, having a tubular body comprising a series of sinusoidal shaped struts along the length of the tubular body. A plurality of curvilinear connectors extend between and are attached to adjacent struts wherein a first end of a connector is attached to a distal face of a proximal strut apex and a second end of a connector is attached to a proximal face of a distal strut apex. A pair of unconnected strut apexes are between pairs of connected apexes. When the tubular body is in a stowed configuration a proximal aperture and a distal aperture are circular and when the tubular body is in a deployed configuration the distal aperture is oblong or ovoid. There is also described a method for inserting a stent for use in creation of an arteriovenous fistula by identifying a candidate artery and a candidate vein and dissecting the candidate vein. Next, inserting a stent into the vein and creating a breach in the candidate artery at a desired angle and location. Next, introducing the stent and vein into the candidate artery and forming the stent into a curvature angle selected to minimize turbulent blood flow in an anastomosis formed by the vein and the artery. Optionally, there is a step of fastening a distal portion of the stent to the artery.

1 . An arteriovenous fistula stent, comprising:
 A tubular body constructed from a biocompatible polymer having an in vivo degradation rate corresponding to the time required for fistula formation comprising a series of sinusoidal shaped struts along the length of the tubular body; and   A plurality of curvilinear connectors extending between and attached to adjacent struts wherein a first end of a connector is attached to a distal face of a proximal strut apex and a second end of a connector is attached to a proximal face of a distal strut apex with a pair of unconnected strut apexes between pairs of connected apexes, wherein when the tubular body is in a stowed configuration a proximal aperture and a distal aperture are circular and when the tubular body is in a deployed configuration the distal aperture is oblong or ovoid.   
     
     
         2 . The stent of  claim 1  wherein the tubular body is constructed of a biocompatible polymer selected from the group consisting of: a (poly)lactic acid, a poly(lactic-co-glycolic acid), a polyglycolide, a copolymer, and a cross-linked polymer. 
     
     
         3 . (canceled) 
     
     
         4 . The stent of  claim 1  wherein the curvilinear connectors have a zig-zag shape. 
     
     
         5 . The stent of  claim 1  wherein the curvilinear connectors have a wave shape. 
     
     
         6 . The stent of  claim 1  wherein when the stent is in a deployed configuration a distal aperture of the stent has a non-circular opening. 
     
     
         7 . The stent of  claim 6  wherein the distal aperture has a circumference and a shape selected based on an anastomosis angle of the stent in use to form an arteriovenous fistula. 
     
     
         8 . The stent of  claim 1  wherein, when the stent is in a deployed configuration shaped into a curvature angle for use to form a fistula, a portion of the curvilinear connectors along an inner radius of the curvature angle are shorter than a portion of the curvilinear connectors along an outer radius of the curvature angle. 
     
     
         9 . The stent of  claim 1  wherein when the stent is formed to facilitate formation of an arteriovenous fistula the stent has a tilted conical trunk and an obtuse curvature angle. 
     
     
         10 . The stent of  claim 1  wherein when the stent is formed to facilitate formation of an arteriovenous fistula a distal aperture of the stent has an ovoid or oblong shape. 
     
     
         11 . The stent of  claim 1  wherein in use to facilitate formation of an arteriovenous fistula there is a circular opening on the proximal end of the tubular body and a non-circular opening on the distal end of the tubular body. 
     
     
         12 . The stent of  claim 1  wherein in use to facilitate formation of an arteriovenous fistula the circumference of a proximal end of the tubular body is less than the circumference of a distal end of the tubular body. 
     
     
         13 . The stent of  claim 1  further comprising: an interwoven mesh of biocompatible polymer materials about the tubular body. 
     
     
         14 . A method for inserting a stent for use in creation of an arteriovenous fistula, comprising the steps of:
 identifying a candidate artery and a candidate vein;   dissecting the candidate vein;   inserting a stent into the vein;   creating a breach in the candidate artery at a desired angle and location;   introducing the stent and vein into the candidate artery;   forming the stent into a curvature angle selected to minimize turbulent blood flow in an anastomosis formed by the vein and the artery; and   fastening a distal portion of the stent to the artery to form an anastomosis.   
     
     
         15 . The method of  claim 14  wherein after the fastening step the anastomosis formed by the vein and the artery forms an anastomosis angle between 90 degrees and 180 degrees. 
     
     
         16 . The method of  claim 15  wherein the anastomosis angle is between 100 degrees and 130 degrees. 
     
     
         17 . The method of  claim 14  the fastening step further comprising: engaging a fastener on the distal portion of the stent with a portion of the artery. 
     
     
         18 . The method of  claim 14  the fastening step further comprising: suturing the distal portion of the stent to the artery. 
     
     
         19 . The method of  claim 14  further comprising: using an angioplasty balloon to expand the vein before or after the inserting step. 
     
     
         20 . The method of  claim 14  wherein after the forming step a portion of the stent is compressed and portion of the stent is expanded. 
     
     
         21 . The method of  claim 14  wherein after the forming step or the fastening step a circumference of the distal aperture of the stent attached to the artery is larger than a circumference of the proximal aperture of the stent within the vein. 
     
     
         22 . The method of  claim 14  wherein after the forming step or the fastening step the distal aperture of the stent attached to the artery is configured into an imperfectly circular shape. 
     
     
         23 . The method of  claim 14  wherein the vein is a cephalic vein and the artery is a radial artery. 
     
     
         24 . The method  claim 14  the forming step further comprising: applying heat to the stent. 
     
     
         25 . The method  claim 14  the forming step further comprising: applying pressure to the stent. 
     
     
         26 . The method  claim 14  wherein the forming step is performed by inserting and inflating a balloon inserted into the stent. 
     
     
         27 . The method  claim 14  further comprising: forming the desired anastomosis angle by inserting a shape tool into the stent distal aperture.