Biliary stent-graft

• US 7,914,568 B2
• Filed: 03/18/2005
• Issued: 03/29/2011
• Est. Priority Date: 01/22/1999
• Status: Active Grant

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: Gore Enterprise Holdings Incorporated
• Inventors: Rivera, Ricardo A, Nilson, Michael C, Hutchinson, Erin B, Cully, Edward H
• Primary Examiner(s): Bui; Vy Q
• Application Number:
  US10/907,067
• Publication Number:
  US 20050154448A1
• Time in Patent Office: 2,202 Days
• Field of Search: 623/1.11, 623/1.12, 623/1.13, 623/1.14, 623/1.15, 623/1.17, 623/1.18, 623 119- 121, 623 144- 116, 606/108, 606/191, 606/194, 606/195
• US Class Current: 623/1.13
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/86 Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/89 the wire-like elements comprising two or more adjacent rings flexibly connected by separate members
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• 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 2250/0039 differing in diameter

Abstract

A stent-graft which is particularly useful for applications in biliary ducts. An expandable stent is provided with a covering of a material which is substantially impervious to body fluids and tissue ingrowth and has an increased resistance to bacterial attachment due to its lack of porosity and reduced surface texture. A preferred covering is porous PTFE film rendered substantially non-porous by a coating of a polymeric material such as FEP. The resulting stent has a thin wall for minimum pre-deployment diameter and for minimum interference with fluid flow through the device after implantation. It has good flexibility, allowing its use in curved ducts.

Claims

1. An endoprosthesis for use in supporting a body conduit, said device comprising

a stent having structural elements arranged in a generally tubular form and interstices between adjacent structural elements,

said stent having a first diameter prior to implantation and a second diameter following implantation wherein said first diameter is smaller than said second diameter,

said stent being provided with a covering over at least a portion of said structural elements, said covering having a thickness extending between inner and outer surfaces of the covering,

wherein the covering comprises a material which is substantially liquid impermeable,

wherein a multiplicity of macroscopic openings are provided through the thickness of the covering, and

wherein one or more of said structural elements provide protruding means extending beyond the generally tubular form for anchoring said stent to said body conduit.

2. An endoprosthesis according to claim 1 wherein the stent is a balloon expandable stent.

3. An endoprosthesis according to claim 1 wherein the stent is a self expanding stent.

4. An endoprosthesis according to claim 1 wherein the stent is a nitinol stent.

5. An endoprosthesis according to claim 4 wherein the stent is nitinol wire.

6. An endoprosthesis according to claim 5 wherein the stent comprises nitinol wire formed into a serpentine pattern which is helically wrapped into the tubular form.

7. An endoprosthesis according to claim 6 wherein the nitinol is a single nitinol wire.

8. An endoprosthesis according to claim 6 wherein one or more apices of the serpentine pattern protrude inwardly from the tubular form.

9. An endoprosthesis according to claim 6 wherein the anchoring means comprise one or more apices of the serpentine pattern which are formed to outwardly protrude beyond the tubular form.

10. An endoprosthesis according to claim 9 wherein the anchoring means comprise one or more outwardly protruding apices which are formed from a wire that is continuous with other apices that do not protrude outwardly beyond the tubular form.

11. An endoprosthesis according to claim 1 wherein the covering is a porous material rendered non-porous or substantially non-porous by a coating.

12. An endoprosthesis according to claim 11 wherein the covering is rendered substantially impermeable to body fluids by a coating process selected from the group consisting of spray coating, imbibing, lamination, powder mixing, powder coating, dispersion mixing, co-coagulation, co-extrusion, melt flow extrusion, draw extrusion and impregnation.

13. An endoprosthesis according to claim 11 wherein the covering is porous expanded polytetrafluoroethylene.

14. An endoprosthesis according to claim 12 wherein the porous expanded polytetrafluoroethylene is rendered non-porous or substantially non-porous by a thermoplastic fluoropolymer coating.

15. An endoprosthesis according to claim 12 wherein the thermoplastic fluoropolymer is fluorinated ethylene propylene.

16. An endoprosthesis according to claim 1 wherein the covering is joined to the stent with an adhesive.

17. An endoprosthesis according to claim 16 wherein the adhesive is a thermoplastic adhesive.

18. An endoprosthesis according to claim 17 wherein the thermoplastic adhesive is a fluoropolymer.

19. An endoprosthesis according to claim 18 wherein the fluoropolymer is fluorinated ethylene propylene.

20. An endoprosthesis according to claim 1 wherein said stent foreshortens less than about 10 percent of its length at its first diameter when deployed to the second diameter.

21. An endoprosthesis according to claim 1 wherein the macroscopic openings are triangular in shape.

22. An endoprosthesis according to claim 1 wherein the covering is less than about 0.4 mm thick.

23. An endoprosthesis according to claim 1 wherein the covering is less than about 0.2 mm thick.

24. An endoprosthesis according to claim 23 wherein the anchoring means comprise one or more apices of the serpentine pattern which are formed to outwardly protrude beyond the tubular form.

25. An endoprosthesis according to claim 1 wherein the covering is less than about 0.1 mm thick.

26. An endoprosthesis according to claim 1 wherein the covering is less than about 0.05 mm thick.

27. An endoprosthesis according to claim 1 wherein longitudinally oriented strips are affixed to the covering.

28. An endoprosthesis according to claim 26 wherein the longitudinally oriented strips attach the stent to the covering.

29. An endoprosthesis according to claim 1 wherein substantially liquid impermeable is indicated by no air leakage during a bubble point test at a pressure of about 13 mm Hg.

30. An endoprosthesis according to claim 1 wherein substantially liquid impermeable is indicated by no air leakage during a bubble point test at a pressure of about 26 mm Hg.

31. An endoprosthesis according to claim 1 wherein substantially liquid impermeable is indicated by no air leakage during a bubble point test at a pressure of about 39 mm Hg.

32. An endoprosthesis according to claim 1 wherein substantially liquid impermeable is indicated by no air leakage during a bubble point test at a pressure of about 52 mm Hg.

33. An endoprosthesis according to claim 1 wherein longitudinally oriented strips are affixed to the covering.

34. An endoprosthesis according to claim 33 wherein the longitudinally oriented strips attach the covering to the stent.

35. An endoprosthesis for use in supporting a body conduit,

said device comprising a stent having a generally tubular form,

said stent having structural elements and interstices between adjacent structural elements,

said stent being provided with a covering over at least a portion of said structural elements, said covering having a thickness extending between inner and outer surfaces of the covering,

wherein the covering comprises a material which is substantially liquid impermeable,

wherein said stent comprises a single wire,

wherein a multiplicity of macroscopic openings are provided through the thickness of the covering, and

wherein one or more of said structural elements provide protruding means extending beyond the generally tubular form for anchoring said stent to said body conduit.

36. An endoprosthesis according to claim 35 wherein the wire comprises nitinol wire.

37. An endoprosthesis according to claim 35 wherein said single wire is formed into a serpentine pattern having apices wherein one or more apices of the serpentine pattern protrude inwardly from the tubular form.

38. An endoprosthesis according to claim 35 wherein the covering comprises porous expanded polytetrafluoroethylene.

39. An endoprosthesis according to claim 38 wherein the porous expanded polytetrafluoroethylene is rendered non-porous or substantially non-porous with a coating of fluorinated ethylene propylene.

40. An endoprosthesis according to claim 35 wherein the covering is joined to the stent with an adhesive.

41. An endoprosthesis according to claim 40 wherein the adhesive is fluorinated ethylene propylene.

42. An endoprosthesis according to claim 35 wherein substantially liquid impermeable is indicated by no air leakage during a bubble point test at a pressure of about 13 mm Hg.

43. An endoprosthesis according to claim 35 wherein substantially liquid impermeable is indicated by no air leakage during a bubble point test at a pressure of about 26 mm Hg.

44. An endoprosthesis according to claim 35 wherein substantially liquid impermeable is indicated by no air leakage during a bubble point test at a pressure of about 39 mm Hg.

45. An endoprosthesis according to claim 35 wherein substantially liquid impermeable is indicated by no air leakage during a bubble point test at a pressure of about 52 mm Hg.