Green fluoropolymer tube and endovascular prosthesis formed using same

• US 20030082324A1
• Filed: 10/30/2001
• Published: 05/01/2003
• Est. Priority Date: 10/30/2001
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Hill, Jason P., Girton, Timothy S., Sogard, David J., Brodeur, Christopher B.
• Granted Patent: US 7,597,775 B2
• Time in Patent Office: Days
• US Class Current: 428/36.9
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• 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 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: B29C 2793/009 after shaping
• CPC Class Codes: B29C 2948/92647 Thickness
• CPC Class Codes: B29C 2948/92857 Extrusion unit
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/10 flexible, e.g. blown foils
• CPC Class Codes: B29C 48/25 Component parts, details or accessories; Auxiliary operations
• CPC Class Codes: B29C 48/32 with annular openings, e.g. for forming tubular articles
• CPC Class Codes: B29C 48/475 using pistons, accumulators or press rams
• CPC Class Codes: B29C 48/793 upstream of the plasticising zone, e.g. heating in the hopper
• CPC Class Codes: B29C 48/83 Heating or cooling the cylinders
• CPC Class Codes: B29C 48/832 Heating
• CPC Class Codes: B29C 48/865 Heating
• CPC Class Codes: B29C 48/902 internally
• CPC Class Codes: B29C 48/92 : Measuring, controlling or regulating
• CPC Class Codes: B29C 55/22 : of tubes B29C61/08 takes precedence
• CPC Class Codes: B29K 2027/18 : PTFE, i.e. polytetrafluorethene , e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29L 2009/00 : Layered products
• CPC Class Codes: B29L 2023/00 : Tubular articles B29L2024/00 takes precedence ; catheters B29L2031/7542
• CPC Class Codes: B29L 2031/7534 : Cardiovascular protheses
• CPC Class Codes: B29L 2031/7542 : Catheters
• CPC Class Codes: C08L 27/18 : Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: Y10T 428/139 : Open-ended, self-supporting conduit, cylinder, or tube-type article

Abstract

The present invention is directed to a green fluoropolymer tube which has a wall thickness of about 250 microns or less, preferably about 200 microns or less, and more preferably about 125 microns or less. With such thinness, the green tube may be formed into a tube of expanded fluoropolymer having a wall thickness of about 250 microns or less, preferably about 200 μm or less and more preferably about 125 microns or less. Such an expanded fluoropolymer tube is particularly well-suited for use as an endovascular prosthesis, such as a graft, or in a stent-graft, because of its flexibility and strength.

Claims

1. A green fluoropolymer tube comprising a wall having an inner surface and an outer surface, a thickness being generally uniformly defined between said inner and outer surfaces, said thickness being in the range of up to about 250 μ

m.

2. A tube as in claim 1, wherein said wall is seamless.

3. A tube as in claim 1, wherein said tube is extruded.

4. A tube as in claim 1, wherein said tube is generally cylindrical, said inner surface having a diameter of about 1 mm to about 14 mm.

5. A tube as in claim 1, wherein said tube is generally cylindrical, said outer surface having a diameter of about 1 mm to about 14 mm.

6. A tube as in claim 1, wherein said tube is coreless.

7. A tube as in claim 1, wherein said fluoropolymer is PTFE.

8. A tube as in claim 1, wherein said thickness being in the range of up to about 200 m.

9. A tube as in claim 8, wherein said thickness being in the range of up to about 125 m.

10. An implantable tubular prosthesis comprising a first tube including a seamless first wall having a first inner surface and a first outer surface, a first thickness being defined between said first inner and first outer surfaces, said first thickness being in the range of about 250 μ

m or less, said first wall including an expanded fluoropolymer.

11. A prosthesis as in claim 10, wherein said first thickness is in the range of about 200 μ

m. or less.

12. A prosthesis as in claim 11, wherein said first thickness is in the range of about 125 μ

m or less.

13. A prosthesis as in claim 10, wherein said first tube is extruded.

14. A prosthesis as in claim 10, wherein said fluoropolymer is PTFE.

15. A prosthesis as in claim 10 further comprising a distensible member concentrically disposed relative to said first tube.

16. A prosthesis as in claim 15, wherein said distensible member is disposed about said first tube.

17. A prosthesis as in claim 16, further comprising a second tube disposed about said distensible member.

18. A prosthesis as in claim 17, wherein said distensible member includes interstices, said first tube being bonded to said second tube through said interstices.

19. A prosthesis as in claim 18, wherein said distensible member is non-bondedly disposed between said first and second tubes.

20. A prosthesis as in claim 15, wherein said first tube is disposed about said distensible member.

21. A prosthesis as in claim 15, wherein said distensible member is at least partially recessed into said first tube.

22. A prosthesis as in claim 16 wherein the wall thickness of said prosthesis, exclusive of said distensible member, is about 120 μ

m or less.

23. A process for forming a prosthesis, comprising the step of:

extruding a fluoropolymer to form a tubular member having a wall with an inner surface and an outer surface, a thickness being defined between said inner and outer surfaces, said thickness being in the range of about 250 μ

m or less.

24. A process as in claim 23, wherein said fluoropolymer is PTFE.

25. A process as claim 23, wherein said tubular member is hollow upon extrusion.

26. A process as in claim 23 further comprising:

at least partially expanding said tubular member.

27. A process as in claim 23 further comprising:

disposing a distensible member concentrically relative to said expanded tubular member.

28. A process as in claim 27, wherein said distensible member is disposed in contiguous contact with said inner surface.

29. A process as in claim 27, wherein said distensible member is disposed in contiguous contact with said outer surface.

30. A process as in claim 27, wherein said distensible member is at least partially recessed within said expanded tubular member.

31. A process as in claim 27 further comprising extruding a fluoropolymer to form a second tubular member having a second wall with a second inner surface and a second outer surface, a second thickness being defined between said second inner and second outer surfaces, said second thickness being in the range of about 250 μ

m or less;

at least partially expanding said second tubular member; and

disposing said second expanded tubular member concentrically relative to said expanded tubular member.

32. A process as in claim 31, wherein said fluoropolymer is PTFE.

33. A process as in claim 31, wherein said distensible member is interposed between said expanded tubular member and said second expanded tubular member.

34. A process as in claim 33, wherein said distensible member includes interstices, said expanded tubular member being bonded to said second expanded tubular member through said interstices.

35. A process as in claim 34, wherein said distensible member is non-bondedly disposed between said expanded tubular member and said second expanded tubular member.

36. A process as in claim 26, wherein said tubular member is expanded through about 500 to about 6000% of elongation.

37. A process as in claim 31, wherein said second tubular member is expanded through about 500 to about 6000% of elongation.

38. A process as in claim 23, wherein said thickness being in the range of about 200 μ

m or less.

39. A process as in claim 38, wherein said thickness being in the range of about 125 μ

m or less.

40. A process as in claim 23, wherein tension is applied to said tubular member during extruding.

41. A process for forming a green tube, said process comprising extruding a fluoropolymer to form a tubular member having a wall with an inner surface and an outer surface, a thickness being generally uniformly defined between said inner and outer surfaces, said thickness being in the range of about 250 μ

m or less.

42. A process as in claim 41, wherein said thickness is in the range of about 200 μ

m or less.

43. A process as in claim 42, wherein said thickness is in the range of about 125 μ

m or less.

44. A process as in claim 41, wherein said tube is cylindrical, said inner surface having a diameter of about 1 mm to about 14 mm.

45. A process as in claim 41, wherein said outer surface has an outer diameter of about 1 mm to about 14 mm.

46. A process as in claim 41, wherein said tubular member is hollow upon extrusion.

47. A process as in claim 41 further comprising injecting a stable medium inside of said inner surface to provide structural support for said tubular member.

48. A process as in claim 47, wherein said stable medium is air.

49. A process as in claim 41, wherein said fluoropolymer is PTFE.

50. A process as in claim 41, wherein tension is applied to said tubular member during extruding.

51. A method of forming a stent-graft device comprising the steps of:

forming an expandable fluoropolymeric tube from an extruded green fluoropolymer tube having a wall thickness of about 250 μ

m or less; and

dispensing a distensible member concentrically thereabout.

52. A method as in claim 51 further comprising:

dispensing a second expandable fluoropolymeric tube formed from an extruded green fluoropolymer tube having a wall thickness of about 250 μ

m or less about said distensible member.

53. A method as in claim 51 further including the step of joining together said tubes.

54. A method as in claim 53 wherein said joining includes the use of heat and pressure.

55. A method as in claim 53 wherein said joining includes the use of adhesive.

56. A method as in claim 51, wherein said wall thickness is about 200 μ

m or less.

57. A method as in claim 56, wherein said wall thickness is about 125 μ

m or less.

58. A method as in claim 52, wherein said wall thickness of said second tube being about 200 μ

m or less.

59. A method as in claim 58, wherein said wall thickness of said second tube being about 125 μ

m or less.