Stent deployment systems and methods

• US 20040249435A1
• Filed: 06/09/2003
• Published: 12/09/2004
• Est. Priority Date: 06/09/2003
• Status: Active Grant

• Current Assignee: JW Medical Systems Ltd
• Original Assignee: XTENT, Inc.
• Inventors: Andreas, Bernard, Grainger, Jeffry J., Snow, David W.
• Granted Patent: US 7,241,308 B2
• Time in Patent Office: Days
• US Class Current: 623/1.12
• 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 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2002/826 more than one stent being applied sequentially
• CPC Class Codes: A61F 2002/9583 Means for holding the stent on the balloon, e.g. using protrusions, adhesives or an outer sleeve
• CPC Class Codes: A61F 2250/0039 differing in diameter

Abstract

A stent deployment system includes a catheter shaft, an expandable member mounted to the catheter shaft, and one or more stents or stent segments slidably positioned on the expandable member. The stent deployment system is adapted for deployment of stents or stent segments in very long lesions and in tapered and curved vessels. The stent deployment system facilitates slidable movement of a stent in a distal direction relative to the expandable member while inhibiting slidable movement in a proximal direction relative to the expandable member.

Claims

1. A stent deployment system for deploying one or more stents in a blood vessel having a luminal taper, the stent deployment system comprising:

an elongated catheter shaft having a proximal end and a distal end;

an expandable member mounted to the catheter shaft near the distal end, the expandable member having a proximal extremity and a distal extremity, the proximal extremity having a first expanded diameter and the distal extremity having a second expanded diameter, the first expanded diameter being larger than the second expanded diameter in general correspondence to the luminal taper; and

a plurality of independent stent segments slidably positionable on the proximal and distal extremities for expansion therewith, each stent segment being independently expandable to an expanded diameter potentially different than at least one other stent segment;

wherein the expandable member has an outer surface suitable for slidable advancement of the stent segments thereon from the proximal extremity to the distal extremity.

2. The stent deployment system of claim 1 wherein at least one of the first and second extremities of the expandable member has an axial length selected to accommodate a pre-selected number of stent segments.

3. The stent deployment system of claim 1 wherein the pre-selected number of stent segments is one.

4. The stent deployment system of claim 1 wherein at least one of the first and second extremities has a constant outer diameter.

5. The stent deployment system of claim 1 wherein at least one of the first and second extremities has a tapered outer diameter.

6. The stent deployment system of claim 5 wherein both of the first and second extremities are tapered.

7. The stent deployment system of claim 4 wherein another of the first and second extremities has a constant outer diameter.

8. The stent deployment system of claim 1 wherein the proximal and distal extremities are contiguous.

9. The stent deployment system of claim 8 wherein the outer surface is continuously tapered along the proximal and distal extremities.

10. The stent deployment system of claim 1 wherein the expandable member has a proximal end portion fixed to the catheter shaft at a first location and a distal end portion fixed to the catheter shaft at a second location, the proximal end portion having a reverse taper between the first location and the proximal extremity, the distal end portion having a distal taper between the distal extremity and the second location, the expandable member being tapered between the proximal end portion and the distal end portion at a slope substantially less than the slope of the distal taper.

11. The stent deployment system of claim 9 wherein the outer surface is tapered at a slope of about 0.5 to 5%.

12. The stent deployment system of claim 1 wherein the first diameter is about 3-5 mm and the second diameter is about 2-4 mm.

13. The stent deployment system of claim 1 further comprising a pusher for slidably advancing the stent segments distally relative to the expandable member.

14. The stent deployment system of claim 13 wherein the pusher comprises a tubular member slidably disposed over the catheter shaft and having a distal end for engaging a stent segment.

15. The stent deployment system of claim 1 wherein the expandable member is adapted to expand a first plurality of stent segments simultaneously while a second plurality of stent segments remains unexpanded.

16. The stent deployment system of claim 15 further comprising a sheath slidably disposed over at least a proximal portion of the expandable member, the second plurality of stent segments being disposed on the proximal portion, the sheath being configured to restrain expansion of the proximal portion and the second plurality of stents.

17. The stent deployment system of claim 1 wherein the outer surface comprises a series of steps of decreasing outer diameter as the distal end is approached.

18. The stent deployment system of claim 17 wherein each step has an axial length selected to accommodate a pre-selected number of stent segments.

19. The stent deployment system of claim 18 wherein the pre-selected number is one.

20. A stent deployment system for deploying one or more stents in a blood vessel having a luminal taper, the stent deployment system comprising:

an elongated catheter shaft having a proximal end and a distal end;

an expandable member mounted to the catheter shaft near the distal end, the expandable member being tapered when expanded from a first expanded diameter in a proximal extremity thereof to a second expanded diameter in a distal extremity thereof in general correspondence to the luminal taper; and

a plurality of independent stent segments slidably positionable over the expandable member to locations on the proximal and distal extremities for expansion therewith, each stent segment being independently expandable to an expanded diameter potentially different than at least one other stent segment;

wherein the expandable member has an outer surface between the proximal and distal extremities suitable for slidable advancement of the stent segments thereon.

21. The stent deployment system of claim 20 wherein the expandable member is tapered continuously from the first expanded diameter to the second expanded diameter.

22. The stent deployment system of claim 20 wherein the expandable member has a proximal end portion fixed to the catheter shaft at a first location and a distal end portion fixed to the catheter shaft at a second location, the proximal end portion having a reverse taper between the first location and the proximal extremity, the distal end portion having a distal taper between the distal extremity and the second location, the expandable member being tapered between the proximal end portion and the distal end portion at a slope substantially less than the slope of the distal taper.

23. The stent deployment system of claim 20 wherein the expandable member is tapered at a slope of about 0.5-5%.

24. The stent deployment system of claim 20 wherein the first diameter is about 3-5 mm and the second diameter is about 2-4 mm.

25. The stent deployment system of claim 20 further comprising a pusher for slidably advancing the stent segments distally relative to the expandable member.

26. The stent deployment system of claim 25 wherein the pusher comprises a tubular member slidably disposed over the catheter shaft and having a distal end for engaging a stent segment.

27. The stent deployment system of claim 20 wherein the expandable member is adapted to expand a first plurality of stent segments simultaneously while a second plurality of stent segments remains unexpanded.

28. The stent deployment system of claim 27 further comprising a sheath slidably disposed over at least a proximal portion of the expandable member, the second plurality of stent segments being disposed on the proximal portion, the sheath being configured to restrain expansion of the proximal portion and the second plurality of stents.

29. A method of deploying stent segments in a blood vessel having a luminal taper, the method comprising:

transluminally introducing a catheter into the blood vessel, the catheter having an expandable member near a distal end thereof;

positioning a first plurality of independent stent segments over the expandable member such that a first stent segment is on a proximal extremity of the expandable member and a second stent segment is on a distal extremity of the expandable member, the first and second stent segments being independently movable relative to the expandable member; and

expanding the expandable member such that the proximal extremity has a first expanded diameter and the distal extremity has a second expanded diameter smaller than the first expanded diameter, wherein the first stent segment is expanded to a diameter larger than the second stent segment.

30. The method of claim 29 further comprising, after expanding the expandable member, slidably positioning a second plurality of independent stent segments over the expandable member with the catheter remaining in the blood vessel.

31. The method of claim 29 further comprising constraining a proximal portion of the expandable member from expansion while a distal portion of the expandable member is expanded, the proximal and distal extremities being in the distal portion.

32. The method of claim 31, wherein at least a third stent segment is slidably disposed on the proximal portion.

33. The method of claim 31, wherein the expandable member is constrained by a sheath slidably disposed over the proximal portion of the expandable member.

34. The method of claim 30, wherein the second plurality of independent stent segments is slidably positioned over the expandable member by a pusher slidably coupled to the catheter.

35. The method of claim 30, wherein the second plurality of independent stent segments is slidably positioned over the expandable member by retracting the expandable member relative to the second plurality of independent stent segments.

36. The method of claim 29, wherein the first plurality of independent stent segments is positioned over the expandable member while the catheter is disposed in the blood vessel.

37. The method of claim 29, wherein the expandable member is tapered between the proximal extremity and the distal extremity when expanded.

38. The method of claim 37, wherein the expandable member is tapered when expanded to correspond generally with the luminal taper.

39. The method of claim 29, wherein the proximal extremity has a first axial length of a first constant diameter and the distal extremity has a second axial length of a second constant diameter when the expandable member is expanded.

40. The method of claim 39, wherein the first and second axial lengths are approximately equal.

41. The method of claim 39, wherein the first and second axial lengths correspond to the length of a stent segment.

42. The method of claim 29, wherein the expandable member is expanded to an expanded configuration comprising a plurality of steps of decreasing diameter between the proximal and distal extremities.

43. The method of claim 42, wherein each step has an axial length selected to accommodate a pre-selected number of stent segments.

44. The method of claim 42, wherein the pre-selected number is one.

45. The method of claim 29, further comprising positioning a third stent segment on the expandable member adjacent to the first stent segment and positioning a fourth stent segments on the expandable member adjacent to the second stent segment, the third stent segment being expanded to a diameter larger than the fourth stent segment.

46. The method of claim 45, wherein the third stent segment is expanded to a diameter different than the first stent segment and the fourth stent segment is expanded to a diameter different than the second stent segment.

47. A stent deployment system comprising:

an elongated catheter shaft having a proximal end and a distal end;

an expandable member mounted to the catheter shaft near the distal end, the expandable member having a plurality of surface features projecting outwardly therefrom; and

a stent slidably positionable over the expandable member, wherein the surface features allow sliding movement of the stent distally relative to the expandable member and inhibit sliding movement of the stent proximally relative to the expandable member.

48. The stent deployment system of claim 47, wherein the surface features comprise flexible and resilient projections.

49. The stent deployment system of claim 48, wherein the projections normally point in a distal direction from the expandable member.

50. The stent deployment system of claim 48, wherein the projections are deflectable so the projections point in a proximal direction from the expandable member.

51. The stent deployment system of claim 48, wherein the projections extend from the expandable member at an angle, the angle being variable by manipulating the expandable member.

52. The stent deployment system of claim 51, wherein the angle is variable by inflation of the expandable member.

53. The stent deployment system of claim 51, wherein the angle is variable by tensioning the expandable member.

54. The stent deployment system of claim 47, wherein the surface features comprise flexible and resilient ribs.

55. The stent deployment system of claim 54, wherein the ribs have a curvature so as to be convex on a proximal side thereof, the curvature being selected to allow distal movement of the stent over the rib.

56. The stent deployment system of claim 55, wherein the ribs have a distal side configured to engage the stent to inhibit proximal movement thereof.

57. The stent deployment system of claim 55, wherein the ribs are deflectable to allow proximal movement of the stent over the rib.

58. The stent deployment system of claim 47, wherein the surface features are configured to engage the stent, further comprising means for varying the degree of engagement of the stent by the surface features.

59. A stent deployment system comprising:

an elongated catheter shaft having a proximal end and a distal end;

an expandable member mounted to the catheter shaft near the distal end, the expandable member having an outer surface; and

a stent slidably positionable over the outer surface of the expandable member, wherein the outer surface is configured to allow sliding movement of the stent distally relative to the expandable member and inhibit sliding movement of the stent proximally relative to the expandable member.

60. The stent deployment system of claim 59, wherein the outer surface comprises a plurality of projections projecting outwardly therefrom.

61. The stent deployment system of claim 60, wherein the plurality of projections point generally in a distal direction to facilitate movement of the stent distally relative thereto and to inhibit movement of the stent proximally relative thereto.

62. The stent deployment system of claim 61, wherein the projections are resiliently deflectable so as to point generally in a proximal direction.

63. The stent deployment system of claim 60, wherein the projections project at an angle from the outer surface, the angle being variable in response to tension in the outer surface.

64. The stent deployment system of claim 63, wherein the angle is variable in response to inflation of the expandable member.

65. The stent deployment system of claim 59, wherein the outer surface comprises a plurality of ribs configured to engage the stent.

66. The stent deployment system of claim 65, wherein the ribs are convex on a proximal side thereof.

67. The stent deployment system of claim 66, wherein the ribs have a distal side configured to inhibit proximal movement of the stent.

68. The stent deployment system of claim 65, wherein the ribs are deflectable to allow movement of the stent proximally relative thereto.