Procedures for introducing stents and stent-grafts

• US 20030208260A1
• Filed: 05/09/2003
• Published: 11/06/2003
• Est. Priority Date: 09/08/1994
• Status: Abandoned Application

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Inventors: Lam, Sharon, Maroney, Charles T., Lau, Lilip, Hartigan, William M.
• Application Number:
  US10/434,122
• Publication Number:
  US 20030208260A1
• Time in Patent Office: Days
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/844 folded prior to deployment
• 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 2/89 the wire-like elements comprising two or more adjacent rings flexibly connected by separate members
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2/92 Stents in the form of a rolled-up sheet expanding after insertion into the vessel , e.g. with a spiral shape in cross-section
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2002/061 provided with means for allowing access to secondary lumens
• 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 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30462 retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2002/828 Means for connecting a plurality of stents allowing flexibility of the whole structure
• CPC Class Codes: A61F 2002/91508 the meander having a difference in amplitude along the band
• CPC Class Codes: A61F 2002/91516 the meander having a change in frequency along the band
• CPC Class Codes: A61F 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2002/9511 : the retaining means being filaments or wires
• CPC Class Codes: A61F 2002/9665 : with additional retaining means
• CPC Class Codes: A61F 2210/0019 : operated at only one temperature whilst inside or touching the human body, e.g. constrained in a non-operative shape during surgery, another temperature only occurring before the operation
• CPC Class Codes: A61F 2220/0075 : sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2230/0039 : H-shaped
• CPC Class Codes: A61F 2230/0041 : J-shaped
• CPC Class Codes: A61F 2230/006 : Y-shaped
• CPC Class Codes: A61F 2230/0078 : hyperboloidal
• CPC Class Codes: A61F 2250/0098 : radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00137 : Tungsten or W-based alloys
• CPC Class Codes: A61F 2310/00149 : Platinum or Pt-based alloys

Abstract

This invention is a medical device and a method of using it. The device is a foldable stent or stent-graft which may be percutaneously delivered with (or on) a catheter, typically an endovascular catheter, to a body cavity or lumen and then expanded. It may also be delivered or via surgical (or other) techniques. The expandable stent structure utilizes torsional members which distribute bending and folding loads in such a way that the stent is not plastically deformed. The stent'"'"'s configuration allows it to be folded or otherwise compressed to a very small diameter prior to deployment without changing the length of the stent. The graft component cooperating with the stent is tubular and preferably is blood-compatible material which may, if desired, be reinforced with fibers. The stent is able to provide collapsible support for otherwise frangible graft material.

The invention also involves procedures for folding stents and for deploying stents or stent-grafts which have been folded, bound, or otherwise collapsed to significantly smaller diameters for insertion into a human or animal body. When used with super-elastic alloys, the stent may be collapsed at a convenient temperature either above or, preferably, below the transition temperature of the alloy. The deployment procedures may involve the use of an outer sleeve to maintain the stent or stent-graft at a reduced diameter or may involve one or more external or internal “slip-lines” or “tether wires” to hold and then to release the device.

Claims

1. A method for preparing a self-expanding stent having two ends, a longitudinal axis between those ends, a passageway between those ends, torsion members having a component approximately parallel to said longitudinal axis, said torsion members storing and releasably restoring angular torsion upon flexing of the stent for introduction into a human body comprising:

folding said self-expanding stent along the longitudinal axis to form at least one fold line.

2. The method of claim 1 further including the step of introducing a removable slip line into the stent to maintain the stent in a folded condition.

3. The method of claim 2 in which the self-expanding stent comprises loops along at least one fold line in the stent through which the slip line is introduced.

4. The method of claim 2 in which the removable slip line is woven into the stent at a fold line using a sack knot so to allow removal of the slip line by unweaving the sack knot through axial movement of the slip line.

5. The method of claim 1 in which the stent is metallic.

6. The method of claim 1 in which the stent is a super-elastic alloy.

7. The method of claim 1 in which the stent is nitinol.

8. The method of claim 1 where the stent comprises at least one helically aligned torsion member having undulating elements defining said passageway.

9. The method of claim 8 where the stent additionally comprises at least one flexible link passing through said helically aligned torsion member and maintaining said at least one helically aligned torsion member in alignment.

10. The method of claim,8 where the stent additionally comprises at least one flexible link passing through said undulating elements on adjacent helical turns.

11. The method of claim 9 where said undulating elements are arranged in an intercooperating phased relationship between adjacent helical turns.

12. The method of claim 11 where said flexible link maintains said undulating elements in phased relationship between adjacent helical turns.

13. The method of claim 1 where the stent comprises at least one ring assembly extending circumferentially about said passageway, said ring assembly containing at least one torsion member approximately parallel to said axis, said torsion member being situated so that when said ring assembly is distorted, said torsion member is twisted.

14. The method of claim 1 further comprising a graft attached to the stent.

15. The method of claim 14 in which the graft is a polymeric nonthrombogenic material.

16. The method of claim 14 where the graft comprises a material selected from DACRON, TEFLON, KEVLAR, GORETEX, and porous polyurethane.

17. The method of claim 14 where the graft comprises a collagen-based material.

18. The method of claim 14 where the graft additionally comprises reinforcing fibers within said tubular member.

19. The method of claim 14 where the tubular member additionally comprises radiopaque fibers within said tubular member.

20. A method for the introduction into a human body of a self-expanding stent having two ends, a longitudinal axis between those ends, a passageway between those ends, torsion members having a component approximately parallel to said longitudinal axis, said torsion members storing and releasably restoring angular torsion upon flexing of the stent, which stent has been folded along said longitudinal axis to form one or more fold lines, comprising the steps of:

introducing said folded self-expanding stent to a selected site in a human body,

releasing the folded self-expanding stent so to allow the stent-graft to expand at the selected site in the body.

21. The method of claim 20 in which the selected site is a vascular site.

22. The method of claim 20 wherein the stent is maintained in a folded condition prior to release by a removable slip line.

23. The method of claim 20 in which the self-expanding stent comprises loops along at least one fold line in the stent through which the slip line is introduced.

24. The method of claim 22 in which the removable slip line is woven into the stent at a fold line using a sack knot so to allow removal of the slip line by unweaving the sack knot through axial movement of the slip line.

25. The method of claim 20 in which the stent is metallic.

26. The method of claim 20 in which the stent is a super-elastic alloy.

27. The method of claim 20 in which the stent is nitinol.

28. The method of claim 20 where the stent comprises at least one helically aligned torsion member having undulating elements defining said passageway.

29. The method of claim 28 where the stent additionally comprises at least one flexible link passing through said helically aligned torsion member and maintaining said at least one helically aligned torsion member in alignment.

30. The method of claim 28 where the stent additionally comprises at least one flexible link passing through said undulating elements on adjacent helical turns.

31. The method of claim 28 where said undulating elements are arranged in an intercooperating phased relationship between adjacent helical turns.

32. The method of claim 30 where said flexible link maintains said undulating elements in phased relationship between adjacent helical turns.

33. The method of claim 20 where the stent comprises at least one ring assembly extending circumferentially about said passageway, said ring assembly containing at least one torsion member approximately parallel to said axis, said torsion member being situated so that when said ring assembly is distorted, said torsion member is twisted.

34. The method of claim 20 further comprising a graft attached to the stent.

35. The method of claim 34 in which the graft is a polymeric nonthrombogenic material.

36. The method of claim 34 where the graft comprises a material selected from DACRON, TEFLON, KEVLAR, GORETEX, and porous polyurethane.

37. The method of claim 34 where the graft comprises a collagen-based material.

38. The method of claim 34 where the graft additionally comprises reinforcing fibers within said tubular member.

39. The method of claim 34 where the tubular member additionally comprises radiopaque fibers within said tubular member.

40. A prosthetic device for introduction into the human body comprising:

a.) a self-expanding stent suitable for introduction into the body, said stent having two ends, a longitudinal axis between those ends, a passageway between those ends, torsion members having a component approximately parallel to said longitudinal axis, said torsion members storing and releasably restoring angular torsion upon flexing of the stent and wherein the stent is folded along the longitudinal axis to form at least one fold line, and

b.) a removable slip line holding said at least one fold line closed.

41. The device of claim 40 in which the self-expanding stent comprises loops along at least one fold line in the stent through which the slip line is introduced.

42. The device of claim 40 in which the removable slip line is woven into the stent at a fold line using a sack knot so to allow removal of the slip line by unweaving the sack knot through axial movement of the slip line.

43. The device of claim 40 in which the stent is metallic.

44. The device of claim 40 in which the stent is a super-elastic alloy.

45. The device of claim 40 in which the stent is nitinol.

46. The device of claim 40 where the stent comprises at least one helically aligned torsion member having undulating elements defining said passageway.

47. The device of claim 46 where the stent additionally comprises at least one flexible link passing through said helically aligned torsion member and maintaining said at least one helically aligned torsion member in alignment.

48. The device of claim 46 where the stent additionally comprises at least one flexible link passing through said undulating elements on adjacent helical turns.

49. The device of claim 46 where said undulating elements are arranged in an intercooperating phased relationship between adjacent helical turns.

50. The device of claim 48 where said flexible link maintains said undulating elements in phased relationship between adjacent helical turns.

51. The device of claim 40 where the stent comprises at least one ring assembly extending circumferentially about said passageway, said ring assembly containing at least one torsion member approximately parallel to said axis, said torsion member being situated so that when said ring assembly is distorted, said torsion member is twisted.

52. The device of claim 40 further comprising a graft attached to the stent.

53. The device of claim 52 in which the graft is a polymeric nonthrombogenic material.

54. The device of claim 52 where the graft comprises a material selected from DACRON, TEFLON, KEVLAR, GORETEX, and porous polyurethane.

55. The device of claim 52 where the graft comprises a collagen-based material.

56. The device of claim 52 where the graft additionally comprises reinforcing fibers within said tubular member.

57. The device of claim 52 where the graft additionally comprises radiopaque fibers within said tubular member.