Stent retaining mechanisms

• US 20080027528A1
• Filed: 07/31/2006
• Published: 01/31/2008
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Jagger, Karl, Olson, Richard, Sutermeister, Derek, Heidner, Matt, Blix, John, Jennings, Adam, Gregorich, Daniel, Alkhatib, Yousef, Weber, Jan, Godin, Dominick, Gunderson, Richard C., Eidenschink, Tracee, Mickley, Timothy J.
• Granted Patent: US 8,439,961 B2
• Time in Patent Office: Days
• US Class Current: 623/1.11
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2/966 with relative longitudinal movement between outer sleeve and prosthesis, e.g. using a push rod
• CPC Class Codes: A61F 2/97 the outer sleeve being splittable
• 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 2002/9665 with additional retaining means
• CPC Class Codes: A61F 2250/0059 temporary

Abstract

A catheter system comprises a catheter comprising a distal portion, a proximal portion and an inner shaft. The inner shaft comprises a medical device receiving region for receiving and carrying a medical device. The retaining device is at least partially constructed of an electroactive polymer. The retaining device is located on or adjacent to the medical device receiving region. The electroactive polymer of the retaining device has an activated state and an inactivated state. The retaining device is capable of retaining a medical device to the catheter and releasing the medical device from the catheter by transitioning between the activated state and the inactivated state.

Claims

1. A catheter having medical device receiving region, a stent disposed about the medical device receiving region in a reduced state for delivery, and a stent retaining device which is activatable to release the stent, wherein the restraining device includes at least a portion which comprises an electroactive polymer, the electroactive polymer portion having different first and second shapes corresponding to activated and inactivated states of the electroactive polymer, and the restraining device portion configured to effect release of the stent as a result of a shape change in said portion induced by activation or inactivation of the electroactive polymer therein.

2. The catheter of claim 1, wherein the retaining device is at least one hub, the hub having a larger profile when activated than when inactivated.

3. The catheter of claim 2 having an inflation balloon, wherein the at least one hub is located under the balloon.

4. The catheter of claim 2, wherein the hubs provide the stent with protection from low force trauma.

5. The catheter of claim 1, wherein the retaining device is a flexible radiopaque band.

6. The catheter of claim 1, wherein the retaining device is at least one sheath.

7. The catheter of claim 6, wherein the at least one sheath is disposed about the length of the stent in the inactivated state and rolls off the stent when activated.

8. The catheter of claim 6, wherein in the inactivated state the at least one sheath retains the stent to the catheter and in an activated state portions of the sheath break to release the stent from the catheter.

9. The catheter of claim 6, wherein the at least one sheath comprises at least one electroactive polymer, in the inactivated state the sheath expands, in the activated state the sheath contracts to form wings.

10. The catheter of claim 6, wherein the at least one sheath is in the form of a sheet, in the inactivated state the sheath disposed about the stent, in the activated state the sheath unrolled from about the stent.

11. The catheter of claim 6, wherein the at least one sheath has a second sheath disposed thereabout, upon removal of the second sheath from about the medical device receiving region the at least one sheath allows partial expansion of the stent in the inactivated state and full deployment in the activated state.

12. The catheter of claim 1, wherein the retaining device comprises electroactive polymer portions disposed about an inner shaft of the catheter, the electroactive polymer portions disposed between struts of the stent, in the activated state the electroactive polymer portions exerting a force on the stent struts thereby retaining the stent to the catheter, in the inactivated state the electroactive polymer portions contracting such that the stent is free to deploy.

13. The catheter of claim 1, wherein the retaining device comprises electroactive polymer portions disposed about an inner shaft of the catheter, the electroactive polymer portions disposed between struts of the stent, in the activated state the electroactive polymer portions extending radially outward and over a stent strut thereby retaining the stent to the catheter, in the inactivated state the electroactive polymer portions contracting such that the stent is free to deploy.

14. The catheter of claim 1, wherein the retaining device comprises electroactive polymer portions disposed about an inner shaft of the catheter, the electroactive polymer portions extending radially between adjacent struts of the stent, in the activated state the electroactive polymer portions having a head portion that expands to a size larger than the distance between the adjacent struts thereby retaining the stent to the catheter, in the inactivated state the head portion changing shape or size such that the stent is free to deploy.

15. The catheter of claim 1, wherein the retaining device is disposed on a catheter shaft or balloon and comprising multiple extension hooks and multiple loops, in the activated state the extension hooks can extend out and over a stent strut and hook into the loops thereby retaining the stent to the catheter, in the inactivated state the extension hooks can unhook from the loops such that the stent is free to deploy.

16. The catheter of claim 1, wherein the retaining device comprises a sock, in the activated state the sock extends from a portion of a balloon or catheter shaft to over an end of the stent thereby retaining the stent to the balloon or catheter portion, in the inactivated state the sock changing configuration such that the sock is not disposed about an end of the stent such that the stent is free to deploy.

17. The catheter of claim 1, wherein the retaining device comprises electroactive polymer portions disposed on adjacent struts of the stent, in the activated state the electroactive polymer portions contracting and drawing the struts together thereby retaining the stent, in the inactivated state the electroactive polymer portions extending such that the stent is free to deploy.

18. The catheter of claim 1, wherein the retaining device comprises an electroactive polymer cylinder within a retaining sheath, a fluid-filled flexible tube disposed within the cylinder, the cylinder having a lumen defined by inner walls, in the inactivated state the stent is retained within the retaining sheath, in the activated state the cylinder swells such that the lumen becomes smaller thereby forcing fluid within the tube in a distal direction thereby pushing the stent in a distal direction out of the sheath to deploy.

19. The catheter of claim 1 being bifurcated with the stent thereon being bifurcated, the retaining device is at least one bumper, in the activated state each bumper expands radially to protect an end of the bifurcated stent, in the inactivated state the at least one bumper contracts to a profile no greater than that of the stent.

20. The catheter of claim 1 wherein the stent comprises struts and the retaining device is a thin layer including electroactive polymer disposed about an inner shaft of the catheter in the medical device receiving region, the inner shaft having a surface wherein a pattern with a depth is formed, the thin layer disposed within the pattern, the pattern substantially matching that of the struts of the stent such that when crimped the stent struts are embedded within the pattern and held in place as the layer swells and squeezes the stent strut in the activated state, in the inactivated state the layer thins to provide space within the pattern allowing the stent struts to be released and the stent to expand.

21. The catheter of claim 1 wherein the retaining device is cone-shaped in the inactivated state, and folds into wings having a smaller profile in the activated state, the retaining device positioned distal to the stent, the distal end of the retaining device connected to a guide wire in both the activated and inactivated state, a proximal end of the retaining device unconnected to the guide wire and free to expand radially in the inactivated state.

22. The catheter of claim 1, wherein the retaining device is at least one sheath, the sheath having a first diameter in the activated state and a second diameter in the inactivated state, in the inactivated state the sheath retaining the stent in a crimped state, in the activated state the sheath retaining the stent at a larger diameter in a pre-deployed state.

23. A catheter having a stent disposed about the catheter and a filter device activatable to expand, wherein the filter device includes a web portion attached to struts which extend in a longitudinal direction and an expander which comprises an electroactive polymer, the expander having different first and second shapes corresponding to activated and inactivated states of the electroactive polymer, the expander configured to force the struts to pivot and expand as a result of a shape change in said expander induced by activation or inactivation of the electroactive polymer therein.