Methods for improving stent retention on a balloon catheter

• US 8,925,177 B2
• Filed: 07/17/2012
• Issued: 01/06/2015
• Est. Priority Date: 06/19/2006
• Status: Active Grant

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Huang, Bin, Gale, David C., Castro, Daniel
• Primary Examiner(s): Taousakis, Alexander P
• Assistant Examiner(s): Travers, Matthew P
• Application Number:
  US13/551,538
• Publication Number:
  US 20120283814A1
• Time in Patent Office: 903 Days
• Field of Search: 292/82, 294/47, 295/08, 295/15, 297/15, 295/16
• US Class Current: 29/516
• CPC Class Codes: A61F 2/9522 Means for mounting a stent or stent-graft onto or into a placement instrument
• 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 2002/9583 Means for holding the stent on the balloon, e.g. using protrusions, adhesives or an outer sleeve
• CPC Class Codes: A61F 2002/9586 the means being inside the balloon
• CPC Class Codes: B23P 11/005 by expanding or crimping
• CPC Class Codes: Y10T 29/49863 with prestressing of part
• CPC Class Codes: Y10T 29/49913 by constricting outer annulus
• CPC Class Codes: Y10T 29/49925 Inward deformation of aperture or hollow body wall
• CPC Class Codes: Y10T 29/49927 Hollow body is axially joined cup or tube
• CPC Class Codes: Y10T 29/53065 with means to fasten by deformation
• CPC Class Codes: Y10T 29/53987 Tube, sleeve or ferrule

Abstract

A method of crimping a stent on a balloon of a catheter assembly is provided. A polymeric stent is disposed over a balloon in an inflated configuration. The stent is crimped over the inflated balloon to a reduced crimped configuration so that the stent is secured onto the balloon. The balloon wall membrane is wedged or pinched between the strut elements of the stent for increasing the retention of the stent on the balloon.

Claims

1. A method of crimping a stent on a balloon of a catheter assembly, comprising:

providing a polymeric stent disposed over a collapsed balloon, wherein the diameter of the stent as positioned over the balloon is much larger than the diameter of the collapsed balloon;

inflating the balloon to an inflated configuration at least to the inner diameter of the stent with a fluid having a temperature higher than ambient temperature;

heating the balloon to at least a glass transition temperature (T_g) of the polymeric stent; and

concurrently with heating the balloon to at least a glass transition temperature (T_g) of the polymeric stent, crimping the stent over the inflated balloon to a reduced crimped configuration to secure the stent on the balloon using one of a roll crimper, collet crimper and iris of sliding wedge crimper.

2. The method of claim 1, wherein the inflated configuration is equal to or less than an intended expansion configuration of the balloon.

3. The method of claim 1, wherein the inflated configuration is a configuration which provides for a membrane or wall of the balloon to protrude into gaps between structural elements of the stent.

4. The method of claim 1, wherein subsequent to crimping the stent on the balloon, a membrane or wall of the balloon is pinched or wedged between structural elements of the stent.

5. The method of claim 1, wherein during the crimping process, the pressure in the balloon is controllably released by a valve.

6. The method of claim 1, wherein the reduced crimped configuration comprises a larger diameter than the diameter of the collapsed balloon.

7. The method of claim 1, wherein the stent is a biodegradable polymeric stent.

8. The method of claim 1, wherein the stent is a biodegradable polymeric stent with or without a biodegradable metallic component.

9. The method of claim 1, wherein inflating the balloon radially expands the stent to a certain degree.

10. The method of claim 1, wherein the one of a roll crimper, collet crimper and iris of sliding wedge crimper includes jaws configured to move inward.

11. The method of claim 1, wherein inflating the balloon to at least the inner diameter of the stent occurs prior to crimping the stent to the reduced crimped configuration.

12. The method of claim 1, further comprising at least partially deflating the balloon, and further wherein crimping the stent comprises maintaining the stent at the reduced crimped configuration for a duration of time prior to at least partially deflating the balloon.

13. The method of claim 1, further comprising at least partially deflating the balloon while crimping the stent to the reduced crimped configuration.

14. The method of claim 1, wherein the polymeric stent comprises a metallic material.

15. The method of claim 1, wherein the polymeric stent comprises a polymer coating.

16. A method of crimping a stent on a balloon, comprising the following acts in the order as listed:

(a) providing a polymer stent disposed over a balloon in an inflated configuration, the balloon being inflated by a fluid at a temperature of at least a glass transition temperature (T_g) of the polymer stent;

(b) concurrently with the balloon being inflated by a fluid at a temperature of at least a glass transition temperature (T_g) of the polymer stent, crimping the stent to a first reduced diameter;

(c) at least partially deflating the balloon;

(d) inflating the balloon to at least an inner diameter of the stent; and

(e) crimping the stent to a second reduced diameter.

17. The method of claim 16, wherein the second reduced diameter is a final crimped diameter.

18. The method of claim 16, additionally comprising, following act (e):

(f) at least partially deflating the balloon;

followed by

(g) inflating the balloon to at least an inner diameter of the stent;

followed by

(h) crimping the stent to a third reduced diameter.

19. The method of claim 18, wherein the third reduced diameter is a final crimped diameter.

20. The method of claim 16, wherein a balloon softening fluid is applied to the balloon.

21. The method of claim 16, wherein the crimping is performed using a crimper.

22. The method of claim 16, wherein crimping the stent is performed using one of a roll crimper, collet crimper and iris of sliding wedge crimper.