Method for retaining a vascular stent on a catheter

• US 20070006441A1
• Filed: 09/15/2006
• Published: 01/11/2007
• Est. Priority Date: 04/12/2005
• Status: Active Grant

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Stigall, Jeremy, McNiven, Sean, Durcan, Jonathan, Knott, Boyd
• Granted Patent: US 7,947,207 B2
• Time in Patent Office: Days
• US Class Current: 29/508
• 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 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: B29C 2049/2017 outside the article
• CPC Class Codes: B29C 2049/2412 outside the article
• CPC Class Codes: B29C 2949/08 Preforms made of several individual parts, e.g. by welding or gluing parts together
• CPC Class Codes: B29C 33/3807 Resin-bonded materials, e.g. inorganic particles
• CPC Class Codes: B29C 33/3828 Moulds made of at least two different materials having different thermal conductivities
• CPC Class Codes: B29C 49/20 of articles having inserts or reinforcements ; Handling of inserts or reinforcements
• CPC Class Codes: B29C 49/24 Lining or labelling
• CPC Class Codes: B29K 2105/258 Tubular
• CPC Class Codes: B29L 2031/7542 Catheters
• CPC Class Codes: Y10T 29/49913 by constricting outer annulus

Abstract

A method of securely mounting a stent on a balloon of a catheter. The method generally includes crimping a stent on a balloon of a catheter at least one time, and positioning the balloon with the stent thereon within a polished bore of a mold formed at least in part of a metallic material. The balloon is pressurized and heated within the mold, or within a sheath, in two stages as the stent is restrained from radially expanding. The method may include crimping the stent onto the balloon one or two times during processing. The method increases retention of the stent on the balloon catheter following sterilization.

Claims

1. A method of mounting a stent on a catheter, comprising:

positioning the stent on a balloon of the catheter;

applying a radially compressive force on an outer surface of the stent, thereby decreasing the outer diameter of the stent on the balloon;

pressurizing and heating the balloon while restricting radial expansion of the outer surface of the stent during a first period of time; and

pressurizing and heating the balloon while restricting radial expansion of the outer surface of the stent during a second period of time.

2. The method of claim 1, wherein the pressurizing and heating of the balloon is performed in a mold configured to restrict the radial expansion of the outer surface of the stent.

3. The method of claim 2, wherein the heating of the balloon is performed by applying heat using convection through the mold.

4. The method of claim 2, wherein the stent is a drug delivery stent and mounting the stent on the balloon includes:

mounting the stent on the balloon without damaging the drug delivery layer of the stent; and

heating the balloon by heating the mold by contacting a surface of the mold with a conductive heating element member which heats the mold purely by conduction and which provides temperature control to the mold with a tolerance of about ±

2 degrees Fahrenheit.

5. The method of claim 1, wherein the pressurizing and heating of the balloon during at least one of the first time period and the second time period is performed in a sheath configured to restrict the radial expansion of the outer surface of the stent.

6. The method of claim 1, further including cooling the stent during a third period of time.

7. The method of claim 6, wherein the cooling is controlled.

8. The method of claim 6, wherein the balloon remains pressurized during the cooling.

9. The method of claim 1, further including applying a transient plasticizing agent to the balloon.

10. The method of claim 1, further including applying humidity to the balloon

11. The method of claim 1, wherein the heating of the balloon is performed by applying heat using forced air convection.

12. The method of claim 1, wherein the heating of the balloon is performed by applying heat using an oven.

13. The method of claim 1, wherein restricting radial expansion of the outer surface of the stent restricts the outer surface of the stent to about a final stent outer diameter.

14. The method of claim 1, wherein the second time period has a duration of about 15 seconds to about 48 hours.

15. The method of claim 1, wherein the balloon is heated to a temperature approximately equal to the glass transition temperature of the balloon during at least one of the first time period and the second time period.

16. The method of claim 1, wherein the balloon is pressurized to a pressure of about 1 psi to about 500 psi during at least one of the first time period and the second time period.

17. A method of mounting a stent on a balloon catheter, comprising:

positioning a stent on a balloon catheter, the balloon catheter having an elongated shaft with an inflation lumen and a guidewire lumen and an inflatable balloon on a distal shaft section with an interior in fluid communication with the inflation lumen, and the stent having an open-walled body of stent struts with gaps between adjacent stent struts;

applying at least one radially compressive force on an outer surface of the stent and thereby decreasing the outer diameter of the stent on the balloon catheter;

heating the balloon and introducing inflation media into the interior of the balloon for a first period of time to radially expand the balloon with the stent restrained from radially expanding, wherein the balloon expands into the stent gaps to embed the stent in an outer surface of the balloon;

removing the inflation media from the balloon interior; and

heating the balloon and introducing inflation media into the interior of the balloon for a second period of time to radially expand the balloon with the stent restrained from radially expanding, wherein the balloon expands into the stent gaps to embed the stent in an outer surface of the balloon.

18. The method of claim 17, further including sterilizing the stent mounted on the balloon catheter.

19. The method of claim 17, wherein the at least one radially compressive force is applied by a crimping apparatus.

20. The method of claim 17, wherein the at least one radially compressive force is applied by a hand tool.

21. The method of claim 17, wherein the at least one radially compressive force is applied by hand.

22. The method of claim 17, wherein the stent is restrained from radially expanding by a mold.

23. The method of claim 22, wherein the mold is a split mold and the balloon catheter with the stent mounted thereon is removed from the split mold by opening of the split mold.

24. The method of claim 17, wherein the stent is restrained from radially expanding by a sheath.

25. A method of increasing retention of an intravascular device on a balloon catheter, comprising:

crimping the intravascular device onto a balloon of the balloon catheter;

a first stage of heating and pressurizing the balloon; and

a second stage of heating and pressurizing the balloon.

26. The method of claim 25, further including crimping the intravascular device onto the balloon of the balloon catheter at least one additional time.

27. The method of claim 25, further including restraining radial expansion of the stent in a sheath during the first stage of heating and pressurizing the balloon.

28. The method of claim 25, further including restraining radial expansion of the stent in a sheath during the second stage of heating and pressurizing the balloon.