Low profile, high stretch, low dilation knit prosthetic device

• US 20030204241A1
• Filed: 04/09/2003
• Published: 10/30/2003
• Est. Priority Date: 07/03/2001
• Status: Active Grant

• Current Assignee: Lifeshield Sciences LLC (Acacia Research Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Dong, Jerry Q.
• Granted Patent: US 6,939,372 B2
• Time in Patent Office: Days
• US Class Current: 623/1.13
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/88 the wire-like elements formed as helical or spiral coils forming a net-like or mesh-like structure A61F2/90
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2002/065 Y-shaped blood vessels
• CPC Class Codes: A61F 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61F 2002/075 the stent being loosely attached to the graft material, e.g. by stitching
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: D04B 21/00 Warp knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes
• CPC Class Codes: D04B 21/16 incorporating synthetic threads
• CPC Class Codes: D10B 2331/04 polyesters, e.g. polyethylene terephthalate [PET]
• CPC Class Codes: D10B 2401/04 Heat-responsive characteristics
• CPC Class Codes: D10B 2509/06 Vascular grafts; stents
• CPC Class Codes: D10B 2509/08 Hernia repair mesh

Abstract

A radially expandable stent-graft endoprosthesis includes a knitted tubular structure circumferentially disposed and securably attached to the stent. The knitted tubular structure has a warp knit pattern of interlacing yarns with at least a two-needle underlap to provide greater than 50 percent longitudinal stretchability while substantially inhibiting dilation. A knitted tubular graft is combined with an ePTFE liner to form a composite with greater than 50 percent longitudinal stretchability is also provided. The knitted tubular graft also has a warp knit pattern of interlacing yarns with at least a two-needle underlap to provide the longitudinal stretchability while also substantially inhibiting dilation.

Claims

1. An implantable tubular prosthesis capable of longitudinal expansion from a quiescent state to an elongated state comprising:

a radially contractible and longitudinally expandable tubular stent having a quiescent diameter and quiescent length capable of longitudinal expansion to the elongated state having an elongated length and a contracted diameter, wherein the elongated length is greater than the quiescent length and the contracted diameter is smaller than the quiescent diameter, and further wherein said stent is capable of resiliently returning from the elongated state to the quiescent state; and

a knitted tubular graft circumferentially disposed and securably attached to said stent in the quiescent state, said graft having a single layer of yarns to define a single layered wall, said yarns being interlaced into stitches in a knit pattern capable of resilient longitudinal elongation and resilient radial contraction of said graft to the elongated state and having about at least 400 stitches per square centimeter and further having no more than about 1,200 stitches per square centimeter to provide compliancy in the quiescent state;

wherein said knit pattern is a warp knitted pattern of yarns forming a textile layer having an interior surface and an exterior surface, wherein exterior yarns comprise the exterior surface and form loops in the longitudinal direction of said prosthesis, and interior yarns comprise the interior surface and are diagonally shifted over two or more of the exterior yarns in an alternating pattern along a width of said prosthesis before engaging an exterior yarn.

2. The prosthesis of claim 1 wherein the elongated length is at least 50 percent by length greater than the quiescent length;

and

further wherein the elongated length is no more than about 220 percent by length greater than the quiescent length.

3. The prosthesis of claim 1 wherein said graft is substantially fluid-tight in the quiescent state.

4. The prosthesis of claim 1 wherein the interior yarns are diagonally shifted over three exterior yarns to define a three-needle underlap.

5. The prosthesis of claim 1 wherein the interior yarns are shifted over two exterior yarns to define a two-needle underlap.

6. The prosthesis of claim 1 wherein said diagonally shifted yarns inhibit radial expansion of said prosthesis to diameters greater than the quiescent diameter.

7. The prosthesis of claim 1 wherein said single layer of yarns form a graft wall having a thickness of about at least 0.2 millimeters;

and

further wherein single layer of yarns form a graft wall having a thickness of no more than about 0.4 millimeters.

8. The prosthesis of claim 1 further including sutures for securably attaching said graft to said stent.

9. The prosthesis of claim 1 wherein said graft is mechanically attached to said stent.

10. The prosthesis of claim 1 wherein said graft is securably bonded to said stent.

11. The prosthesis of claim 1 wherein said stent has an exterior circumferential surface and further wherein said graft is circumferentially disposed to said exterior surface.

12. The prosthesis of claim 1 wherein said stent has an interior circumferential surface and further including a tubular layer of PTFE circumferentially disposed and securably attached to said interior surface of said stent.

13. The prosthesis of claim 12 wherein said tubular layer of PTFE is a tubular layer of ePTFE.

14. The prosthesis of claim 13 wherein said tubular layer of ePTFE has circumferentially oriented nodes and longitudinally traversing fibrils.

15. The prosthesis of claim 1 wherein said stent is a wire-stent.

16. The prosthesis of claim 1 wherein said graft further includes opposed open ends to define a hollow tubular structure and further wherein one of said open ends of said graft is a bifurcated end having two hollow tubular structures.

17. The prosthesis of claim 16 wherein said stent further includes opposed open ends to define a hollow tubular structure and further wherein one of said open ends of said stent is a bifurcated end having two hollow tubular structures.

18. The prosthesis of claim 12 further including a bonding agent disposed on an exterior surface of said tubular layer of PTFE for securably attaching said tubular layer of PTFE to said stent, to said graft or to said stent and said graft.

19. The prosthesis of claim 1 wherein said pattern has at least about 31 stitches per centimeter in the longitudinal direction of said prosthesis;

and

further wherein said pattern has no more than about 70 stitches per centimeter in the longitudinal direction of said prosthesis.

20. The prosthesis of claim 1 wherein said pattern has at least about 14 stitches per centimeter along the width of said prosthesis;

and

further wherein said pattern has no more than about 25 stitches per centimeter along the width of said prosthesis.

21. An implantable tubular prosthesis capable of longitudinal expansion from a quiescent state to an elongated state comprising:

a radially contractible and longitudinally expandable tubular stent having an interior surface and an exterior surface and further having a quiescent diameter and quiescent length capable of longitudinal expansion to the elongated state having an elongated length and a contracted diameter, wherein the elongated length is greater than the quiescent length and the contracted diameter is smaller than the quiescent diameter, and further wherein said stent is capable of resiliently returning from the elongated state to the quiescent state;

a non-textile tubular member circumferentially disposed and securably attached to said interior surface of said stent;

a knitted tubular graft circumferentially disposed to said exterior surface of said stent and securably attached to said non-textile tubular member, said graft having a single layer of yarns to define a single layered graft wall, said yarns being interlaced into stitches in a knit pattern capable of resilient longitudinal elongation and resilient radial contraction of said graft to the elongated state and having greater than about 350 stitches per square centimeter to provide compliancy in the quiescent state;

wherein said knit pattern is a warp knitted pattern of yarns forming a textile layer having an interior surface and an exterior surface, wherein exterior yarns comprise the exterior surface and form loops in the longitudinal direction of said prosthesis, and interior yarns comprise the interior surface and are diagonally shifted over two or more of the exterior yarns in an alternating pattern along a width of said prosthesis before engaging an exterior yarn; and

further wherein said interior yarns inhibit radial expansion of said exterior yarns to inhibit dilation of said prosthesis.

22. The prosthesis of claim 21 further including a bonding agent disposed on an exterior surface of said non-textile tubular tube for securably attaching said non-textile tubular member to said stent, to said graft or to said stent and said knitted tubular graft.

23. The prosthesis of claim 22 wherein said bonding agent is a polycarbonate urethane adhesive.

24. The prosthesis of claim 21 wherein said non-textile tubular member is a tubular layer of PTFE.

25. The prosthesis of claim 21 wherein said non-textile tubular member is a tubular layer of ePTFE.

26. The prosthesis of claim 25 wherein said tubular layer of ePTFE has circumferentially oriented nodes and longitudinally traversing fibrils.

27. The prosthesis of claim 21 wherein said stent is a wire-stent.

28. The prosthesis of claim 21 further including sutures for securably attaching said graft to said stent.

29. The prosthesis of claim 21 wherein said graft is mechanically attached to said stent.

30. The prosthesis of claim 21 wherein said graft is securably bonded to said stent.

31. An implantable tubular graft comprising:

a knitted tubular graft having a single layer of yarns to define a single layered wall having an interior surface and an exterior surface, said yarns being interlaced into stitches in a knit pattern capable of resilient longitudinal elongation and resilient radial contraction of said graft to the elongated state and having at least about 350 stitches per square centimeter to provide compliancy in the quiescent state; and

a non-textile tubular member circumferentially disposed and securably attached to said interior surface of said knitted tubular graft;

wherein said knit pattern is a warp knitted pattern of yarns forming a textile layer having an interior surface and an exterior surface, wherein exterior yarns comprise the exterior surface and form loops in the longitudinal direction of said graft, and interior yarns comprise the interior surface and are diagonally shifted over two or more of the exterior yarns in an alternating pattern along a width of said graft before engaging an the exterior yarn.

32. The graft of claim 31 further including a bonding agent disposed on an exterior surface of said non-textile tubular member for securably attaching said non-textile tubular member to said graft.

33. The graft of claim 31 wherein said interior yarns are diagonally shifted over from two to three the exterior yarns.

34. The graft of claim 31 wherein said single layer of yarns form a graft wall having a thickness of at least about 0.3 millimeters;

and

further wherein said single layer of yarns form a graft wall having a thickness of no more than about 0.4 millimeters.

35. The graft of claim 31 wherein the longitudinal expansion is at least about 50 percent by length of the length in the quiescent state;

and

further wherein the longitudinal expansion is no more than about 200 percent by length of the length in the quiescent state.

36. The graft of claim 31 wherein said graft has a substantially fluid-tight quiescent state.

37. The graft of claim 31 wherein said yarns are selected from the group consisting of monofilament yarns, multifilament yearns, spun type yarns, flat yarns, twisted yarns, textured yarns, and combinations thereof.

38. The graft of claim 31 wherein said yarns are selected from the group of materials selected from polyesters, polypropylenes, polyethylenes, polyurethanes, polytetrafluoroethylenes or combinations thereof.

39. The graft of claim 38 wherein said polyesters include polyethylene terephthalate polyesters.

40. The graft of claim 31 wherein said yarns are polyethylene terephthalate polyester textured yarns having a denier of at least about 30;

and

further wherein said polyethylene terephthalate polyester textured yarns have a denier of less than about 100.

41. The graft of claim 31 wherein said pattern has at least about 31 stitches per centimeter in the longitudinal direction of the graft;

and

further wherein said pattern has no more than about 70 stitches per centimeter in the longitudinal direction of the graft.

42. The graft of claim 31 wherein said pattern has at least about 14 stitches per centimeter along the width of the graft;

and

further wherein said pattern has no more than about 25 stitches per centimeter along the width of the graft.