Stents with attached looped ends

Abstract

An open frame prosthesis is formed with looped end terminations at its proximal and distal ends. At one end of the prosthesis, the filaments or strands are welded together in pairs to form strand couplings. A plurality of loop segments are connected to the strand couplings, one loop segment for each pair of adjacent strand couplings. In one version of the prosthesis, strands at the opposite end are bent to form looped ends. In another version, loop segments are connected to pairs of strand couplings at both ends of the prosthesis. The loop segments can be connected to the couplings by welding, fusion bonds, or tubes, which are either crimped or heat shrunk.

1 . A method for forming an atraumatic end in a body implantable device, comprising:
 (a) providing a plurality of elongate structural strands;   (b) providing a mandrel having first and second opposed mandrel ends and having pins disposed only at said first and second opposed mandrel ends;   (c) interbraiding the plurality of elongate structural strands between said first and second opposed mandrel ends and between said pins to form an open-frame tubular interbraided structure having first and second opposed ends;   (d) along said second opposed end of said mandrel,
 extending one of the elongate structural strands beyond the pins, and 
 bending the one of the elongate structural strands over the pins to form a loop segment having an arcuate region and opposed axially extending legs; 
   (e) integrally coupling different ones of the elongate structural strands which have not been bent around the pins at said second opposed end of said mandrel together with the opposed axially extending legs of the one of the elongate structural strand which has been bent around the pins; and   (f) repeating steps (d) and (e) until all ends of said plurality of elongate structural strands are coupled to provide an atraumatic end at said second opposed end of said interbraided structure.   
     
     
         2 . The method of  claim 1 , further comprising:
 bending a portion of each of aid plurality of elongate structural strands around said pins along said second opposed end of said mandrel to provide bends defining an atraumatic end at said first opposed end of said interbraided structure.   
     
     
         3 . The method of  claim 2 , wherein the number of loop segments at said second opposed end is one half the number of bends at said first opposed end. 
     
     
         4 . The method of  claim 2 , wherein said tubular interbraided structure consists essentially of said plurality of elongate structural strands. 
     
     
         5 . The method of  claim 1 , wherein the step integrally coupling the elongate strands comprises welding, fusion bonding, adhesive bonding, or securing with hypotubes. 
     
     
         6 . The method of  claim 1 , wherein said plurality of elongate structural strands comprise metallic strands. 
     
     
         7 . The method of  claim 1 , wherein said plurality of elongate structural strands comprise polymeric strands. 
     
     
         8 . The method of  claim 2 , wherein said plurality of elongate structural strands comprise shape memory strands. 
     
     
         9 . The method of  claim 2 , wherein said shape memory strands comprise nitinol strands. 
     
     
         10 . The method of  claim 8 , further comprising:
 heat setting the shape memory strands with the interbraided structure being disposed on the mandrel.   
     
     
         11 . An implantable prosthesis, comprising:
 a plurality of elongate strands interbraided to form an open-frame tubular structure having opposed first and second atraumatic ends;   wherein at said first atraumatic end, all of the strands are bent to form bends;   wherein each end of said elongate strands at said second atraumatic end are coupled to an end of an adjacent elongate strand at said second atraumatic end defining a pair of attached ends; and   a plurality of loop members attached to said elongate strands, each of said plurality of loop members include a pair of ends with a curved loop therebetween;   wherein each of said pair of ends is attached to said pair of attached ends of said elongate strands for attaching said loop members to said tubular structure at said second atraumatic end;   wherein a number of loop members at said second atraumatic end is less than a number of bends at said first atraumatic end.   
     
     
         12 . The implantable prosthesis of  claim 11 , wherein the number of loop members at said second atraumatic end is one half the number of bends at said first atraumatic end. 
     
     
         13 . The implantable prosthesis of  claim 11 , wherein said open-frame tubular structure consists essentially of said plurality of elongate strands. 
     
     
         14 . The implantable prosthesis of  claim 11 , wherein said plurality of elongate structural strands comprise metallic strands. 
     
     
         15 . The implantable prosthesis of  claim 11 , wherein said plurality of elongate structural strands comprise polymeric strands. 
     
     
         16 . The implantable prosthesis of  claim 11 , wherein said plurality of elongate structural strands comprise shape memory strands. 
     
     
         17 . The implantable prosthesis of  claim 16 , wherein said shape memory strands comprise nitinol strands.