Systems and methods for securing graft material to intraluminal devices
View Patent ↗A stent graft having graft material attached to a stent structure while providing a low profile to the stent graft in its crimped state. The graft material may be attached to an internal surface, an external surface, or both the internal surface and the external surface of the stent. The graft material may cover all or part of such surfaces. The stent graft is expandable upon delivery to the intended treatment site. The expandable nature of the stent graft may be accomplished by self-expanding materials, or through other methods, such as balloon expansion, as generally practiced in the art. The stent graft material is comprised of durable biocompatible materials as generally practiced in the art. The stent graft in its crimped state comprises a low profile fluid flow conduit that is preferably percutaneously delivered, but that may be surgically emplaced to the intended treatment site. Interdigitable stitches on alternating struts of a stent, heat riveted sutures in combination with a preformed hole in a portion of the stent and a washer, or a combination of the interdigitable stitches and the heat riveted sutures and corresponding preformed holes and washers are used to secure the graft material to the stent.
1. A stent graft comprising:
an expandable stent having at least one segment comprised of alternating struts, an expanded diameter and a crimped diameter, wherein the alternating struts of each segment form an external surface and an internal cavity of the stent;
graft material secured to the stent and enabling the stent graft to move between the expanded diameter and the crimped diameter;
a series of interdigitable stitches securing the graft material to at least some of the alternating struts and providing a low profile to the stent graft when in the crimped diameter, wherein the interdigitable stitches comprise an even:odd stitch ratio;
at least one suture threaded through the graft material and at least one preformed hole in a portion of the stent; and
at least one washer corresponding to each of the at least one suture, whereby a first end of each suture is heated to expand against a respective one of the at least one preformed hole of the stent, and a second end of each suture is heated to expand against a respective one of the at least one washer being located between the second end of a respective one of at last one suture and the graft material.
2. The stent graft of claim 1 , wherein the expandable stent is comprised of self expanding material.
3. The stent graft of claim 2 , wherein the self-expanding material is at least partially comprised of Nitinol.
4. The stent graft of claim 1 , wherein the expandable stent is a balloon expandable stent.
5. The stent graft of claim 1 , wherein the graft material is comprised of bio-compatlble materials.
6. The stent graft of claim 5 , wherein the biocompatible materials are at least one of woven polyester, Dacron, Teflon, Dyneema, ePTFE, and polyurethane.
7. The stent graft of claim 1 , wherein the even:odd stitch ratiois 3:4.
8. The stent graft of claim 1 , wherein the even:odd stitch ratio is other than 3:4.
9. The stent graft of claim 1 , wherein the interdigitable stitches comprise an even:even stitch ratio sufficiently spaced along the at least some of the alternating shuts so as not to contact one another when the stent is in the crimped diameter.
10. The stent graft of claim 1 , wherein the alternating struts are interconnected, non-connected, or a combination thereof.
11. The stent graft of claim 1 , wherein the suture is a monofilament.
12. The stent graft of claim 1 , wherein the suture is a multi-filament.