Woven prosthesis and method for manufacturing the same
A woven prosthesis, such as a woven vascular graft, woven from warp and weft yarns. Velour warp yarns forming the prosthesis are selectively incorporated into a base layer of the prosthesis so as to provide a bulbous section without compromising the porosity of the prosthesis.
1. An implantable medical prosthesis comprising:
a woven base comprising base warp yarns interwoven with weft yarn passes, the woven base at least partially forming smaller and larger diameter portions of the prosthesis; and
one or more velour yarns forming part of both the smaller and larger diameter portions;
wherein in at least a portion of the larger diameter portion at least one of the one or more velour yarns incorporated into the woven base exhibits a weave pattern consistent with the woven base;
wherein the larger diameter portion is not crimped.
2. The implantable medical prosthesis of claim 1 , wherein within the smaller diameter portion, the at least one of the one or more velour yarns is not incorporated into the woven base and does not exhibit a weave pattern consistent with the woven base.
3. The implantable medical prosthesis of claim 1 , wherein a spacing between the base warp yarns is maintained approximately the same in the smaller and larger diameter portions without adding additional warp yarns to the larger diameter portion beyond that in the smaller diameter portion.
4. The implantable medical prosthesis of claim 1 , wherein an increase in diameter of the prosthesis going from the smaller diameter portion to the larger diameter is effected by increasing spacing between the base warp yarns during weaving of the prosthesis.
5. The implantable medical prosthesis of claim 1 , wherein the spacing between the base warp yarns in the larger diameter portion is made smaller without reducing a diameter of the larger diameter portion by at least one of the one or more velour yarns incorporated into the woven base of the larger diameter portion.
6. The implantable medical prosthesis of claim 1 , wherein the prosthesis is a generally tubular graft and the larger diameter portion lies within a portion of the graft varying in diameter along a longitudinal axis of the graft and the smaller diameter portion lies within a portion of the graft having a generally uniform diameter.
7. The implantable medical prosthesis of claim 1 , wherein the prosthesis is a generally tubular graft and the larger and smaller diameter portions lie within a portion of the prosthesis in diameter along a longitudinal axis of the graft.
8. The implantable medical prosthesis of claim 1 , wherein in at least a portion of the smaller diameter portion the one or more velour yarns exhibit a float that is entirely absent or smaller in the larger diameter portion.
9. The implantable medical prosthesis of claim 1 , wherein a spacing between the base warp yarns in the smaller diameter portion is within 30% of the size of the spacing in the larger diameter portion.
10. The implantable medical prosthesis of claim 1 , wherein a quantity of the base warp yarns and velour yarns is the same in the larger diameter portion as the smaller diameter portion, and wherein the base warp yarns and the velour warp yarns are continuously woven between the smaller diameter portion and the larger diameter portion.
11. The implantable medical prosthesis of claim 1 , wherein the prosthesis comprises a secondary woven layer disposed over at least one of the smaller and larger diameter portions, and wherein a portion of a yarn forming the secondary layer is incorporated into the base layer of the larger portion.
12. The implantable medical prosthesis of claim 1 , wherein a spacing between the base warp yarns in the smaller diameter portion is within 20% of the size of the spacing in the larger diameter portion.
13. The implantable medical prosthesis of claim 1 , wherein a spacing between the base warp yarns in the smaller diameter portion is within 10% of the size of the spacing in the larger diameter portion.