Atraumatic stent and method and apparatus for making the same
A method of braiding a stent includes braiding a number of elongate filaments around a mandrel using tensioned braiding carriers without spooling the filaments to the tensioned braiding carriers to form a braided stent having atraumatic ends.
1 . A braided stent comprising:
a plurality of elongate filaments inter-braided to form a braided tubular structure, the filaments being inter-braided at a braiding angle formed at crossing filament locations;
the braided tubular structure having:
a first region having a first diameter;
a second region having a second diameter which is different from the first diameter; and
a transition region extending between the first region and the second region;
wherein the braiding angle in the first region is 110±3 degrees, the braiding angle in the second region is 110±3 degrees, and the braiding angle in the transition region is 110±3 degrees.
2 . The braided stent of claim 1 , wherein the braided tubular structure includes a first atraumatic end and a second atraumatic end opposite the first atraumatic end.
3 . The braided stent of claim 2 , wherein the plurality of elongate filaments are bent about a medical portion thereof at the first atraumatic end.
4 . The braided stent of claim 2 , wherein the plurality of elongate filaments are bent into closed loops at the second atraumatic end.
5 . The braided stent of claim 4 , wherein the plurality of elongate filaments forming the closed loops are welded together.
6 . The braided stent of claim 1 , wherein the plurality of elongate filaments are selected from the group consisting of metallic filaments, polymeric filaments, and combinations thereof.
7 . The braided stent of claim 1 , wherein the plurality of elongate filaments are metallic filaments.
8 . The braided stent of claim 7 , wherein the plurality of elongate filaments are formed of nitinol.
9 . The braided stent of claim 1 , wherein the plurality of elongate filaments are composite filaments comprising a first metal and a second metal surrounding the first metal.
10 . The braided stent of claim 9 , wherein the first metal is platinum.
11 . The braided stent of claim 10 , wherein the second metal is nitinol.
12 . The braided stent of claim 1 , wherein the braided tubular structure has a one-under and one-over braid pattern.
13 . The braided stent of claim 1 , wherein the braided tubular structure has a two-under and two-over braid pattern.
14 . The braided stent of claim 1 , further comprising a polymeric coating disposed on the braided tubular structure.
15 . The braided stent of claim 14 , wherein the polymeric coating comprises silicone.
16 . The braided stent of claim 1 , wherein the first region of the braided tubular structure extends to a first end of the stent.
17 . The braided stent of claim 16 , wherein the first region of the braided tubular structure is a flared end region.
18 . The braided stent of claim 17 , wherein the second region of the braided tubular structure has a constant diameter along a majority of a length of the stent.
19 . The braided stent of claim 18 , wherein the second region extends to a second end of the stent.
20 . The braided stent of claim 1 , wherein the transition region is a tapered region of the braided tubular structure.