Stent with detachable tethers and method of using same

• US 20020188341A1
• Filed: 05/10/2001
• Published: 12/12/2002
• Est. Priority Date: 05/10/2001
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Elliott, Christopher J.
• Granted Patent: US 6,716,238 B2
• Time in Patent Office: Days
• US Class Current: 623/1.1
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2/9517 handle assemblies therefor
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2002/9505 having retaining means other than an outer sleeve, e.g. male-female connector between stent and instrument
• CPC Class Codes: A61F 2002/9511 the retaining means being filaments or wires

Abstract

A stent delivery system comprising a stent and at least one tether detachably connected to the stent by a connecting member. In one embodiment, the tether may comprise a conductive material and the connecting member may comprise a material subject to degradation upon application of an electrical current. In another embodiment, the connecting member, the stent, and the tether each may have a mechanical strength, where the strength of the connecting member is less than the strength of the stent and the tether. In yet another embodiment, application of electrical current may weaken the connecting member sufficient to enable detachment of the tether. A method of deploying a stent uses the stent delivery device comprising a tether attached to the stent by a connecting member. The tether may be used for accurate positioning of the stent.

Claims

1. A stent delivery system comprising a stent and at least one tether detachably connected to the stent by a connecting member.

2. The system of claim 1 wherein the tether connects to the stent in a proximal location.

3. The system of claim 1 wherein the tether connects to the stent in a distal location.

4. The system of claim 1 wherein the tether connects to the stent in a medial location.

5. The system of claim 1 wherein said at least one tether comprises a plurality of tethers.

6. The system of claim 1 further comprising a handle attached to the tether for at least one of:

assisting in detachment of the detachable connecting member and retracting the tether after detachment.

7. The system of claim 6 wherein the handle further comprises a movable rack attached to the tether and a stationary pinion, a stationary spiral gear attached to the tether and a fixed rack, or a manipulation rod attached to the tether.

8. The system of claim 1 wherein the stent is a balloon-expandable stent.

9. The system of claim 1 wherein the stent is a self-expanding stent or a hybrid self-expanding/balloon-expandable stent.

10. The system of claim 1 wherein the tether comprises a conductive material and the connecting member comprises a material subject to degradation upon application of an electrical current.

11. The system of claim 1 wherein the tether comprises an insulated wire and the connecting member comprises an uninsulated portion of the tether wire.

12. The system of claim 1 wherein the stent comprises a first material and the connecting member comprises a second material that electrolytically corrodes preferentially relative to the first material when energized with a current.

13. The system of claim 12 wherein the first material comprises platinum and the second material comprises passive or active stainless steel.

14. The system of claim 12 wherein the first material comprises passive stainless steel and the second material comprises active stainless steel.

15. The system of claim 10 wherein the stent comprises an insulating covering.

16. The system of claim 10 further comprising a power supply connected to the tether.

17. The system of claim 16 wherein the power supply comprises a 9V battery.

18. The system of claim 10 wherein the connecting member comprises a solder, a brazing paste, or an adhesive.

19. The system of claim 18 wherein the conductive material of the tether comprises a wire having a first impedance, and the material of the connecting member has a second impedance higher than the first impedance.

20. The system of claim 19 wherein the conductive material of the tether comprises a copper-monel wire and the material of the connecting member comprises solder or an adhesive.

21. The system of claim 10 wherein the connecting member, the stent, and the tether each have a mechanical strength, the connecting member having a first mechanical strength prior to application of electrical current and a second mechanical strength after application of an electrical current of sufficient magnitude and duration to degrade the first mechanical strength, wherein the second mechanical strength is less than both the mechanical strength of the tether and the mechanical strength of the stent.

22. The system of claim 21 wherein the first strength, second strength, and third strength are tensile strengths, torsional strengths, compressive strengths, flexural strengths, or a combination thereof.

23. The system of claim 1 wherein the connecting member has a first mechanical strength, the tether has a second mechanical strength, and the stent has a third mechanical strength, wherein the first mechanical strength is less than both the second mechanical strength and the third mechanical strength.

24. The system of claim 23 wherein the first strength, second strength, and third strength are tensile strengths, torsional strengths, compressive strengths, flexural strengths, or a combination thereof.

25. The system of claim 23 wherein the connecting member comprises a first cross-sectional area that is smaller than a second cross-sectional sectional area of the tether and a third cross-sectional area of the stent.

26. The system of claim 1 wherein the stent has a compressed configuration and an expanded configuration, the system further comprising a tubular delivery catheter having a distal portion on which the stent is axially mounted.

27. The system of claim 26 wherein an intermediate portion of the tether is contained within a proximal portion of the delivery catheter and exits the delivery catheter through an exit hole in the catheter proximal of the distal portion on which the stent is mounted, and a proximal end of the tether is connected to a tether handle located outside of the delivery catheter.

28. The system of claim 26 further comprising an inflatable balloon at the distal portion of the delivery catheter.

29. The system of claim 26 further comprising an outer sheath over the compressed stent and the delivery catheter.

30. The system of claim 26 wherein the stent is self-expanding and the system further comprises an outer sheath over the delivery catheter on which the stent is mounted.

31. A stent delivery system comprising:

a tubular self-expanding stent having a compressed configuration and an expanded configuration;

a delivery catheter on which the stent is axially mounted in the compressed configuration; and

one or more tethers wrapped about the stent to hold the stent in the compressed configuration, each tether connected to the stent, to another tether, or a tether harness by a detachable connecting member.

32. The system of claim 31 further comprising an additional tether detachably connected to the stent by a connecting member for maintaining the stent in the deployment location.

33. The system of claim 31 further comprising a handle attached to the tether for assisting in detachment of the detachable connecting member, for retracting each tether after detachment, or both.

34. The system of claim 33 wherein the handle further comprises a movable rack attached to the tether and a stationary pinion, a stationary spiral gear attached to the tether and a fixed rack, or a manipulation rod attached to the tether.

36. The method of claim 35 wherein step (c) further comprises repositioning or reconstraining the stent using the tether once the stent is in an expanded or partially-expanded configuration.

37. The method of claim 35 wherein step (d) comprises applying an electrical current to the tether which causes the connecting member to degrade.

38. The method of claim 35 wherein step (d) comprises applying a tensional or torsional force to the tether which causes the connecting member to detach.

39. The method of claim 35 wherein step (d) further comprises applying an electrical current to the tether which causes the connecting member to degrade prior to applying a tensional or torsional force for causing the connecting member to detach.

40. The method of claim 35 further comprising the steps of:

(a) retracting the detached tether into the delivery device, and

(b) removing the delivery device from the lumen.

41. The method of claim 35 wherein step (c) comprises expanding the stent by inflation of a balloon.

42. The method of claim 35 wherein step (c) comprises self-expansion of the stent.

43. The method of claim 35 comprising deploying a stent to repair an ostial lesion.

35. A method of deploying a stent using a stent delivery device comprising a tether attached to the stent by a connecting member, the method comprising the steps of:

(a) inserting the stent delivery device into a lumen through an access location;

(b) navigating the stent delivery device to a deployment location;

(c) expanding the stent from a compressed configuration to an expanded configuration while using the tether to maintain the stent in the deployment location; and

(d) detaching the tether from the stent.

44. A method for delivering a tubular self-expanding stent having a compressed configuration and an expanded configuration using a system adapted to deliver the stent in the compressed configuration from a proximal access location outside the body to a distal deployment location inside the body, the system comprising the self-expanding stent, a delivery catheter on which the stent is axially mounted in the compressed configuration, and one or more tethers wrapped about the stent to hold the stent in the compressed configuration, each tether connected to the stent, another tether, or a tether harness by a detachable connecting member, the method comprising the steps of:

(a) inserting the stent delivery device into a lumen through the access location;

(b) navigating the stent delivery device to the deployment location;

(c) detaching each tether from its corresponding connecting member;

(d) allowing the stent to self-expand from the compressed configuration to the expanded configuration.

45. The method of claim 44 wherein step (c) comprises applying an electrical current to the tether which causes the connecting member to degrade.

46. The method of claim 44 further comprising the steps of:

(a) retracting the detached tether into the delivery device, and

(b) removing the delivery device from the lumen.