Method for retaining a vascular stent on a catheter

Abstract

A method of securely mounting a stent on a balloon of a balloon catheter. The method generally includes crimping a stent on a balloon of a balloon catheter, and positioning the balloon with the drug delivery 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 as the mold radially restrains the stent from expanding. The stent is re-crimped on the balloon after removal from the mold to increase retention of the stent on the balloon.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a mold useful in a method which embodies features of the invention, in which a drug delivery stent is mounted onto a balloon catheter.

FIG. 2 is an isometric view of the mold of FIG. 1 in a closed configuration, illustrating a distal section of a balloon catheter within the mold.

FIG. 3 is a longitudinal cross sectional view illustrating the mold of FIG. 2 with heating platens on an outer surface of the mold during a method of mounting a drug delivery stent on the balloon of the balloon catheter.

FIG. 4 is a diagrammatic transverse cross section of the assembly of FIG. 3, taken along line 4-4.

FIG. 5 is a perspective view of the mold of FIG. 3 in an open configuration allowing for removal from the mold of the stent delivery balloon catheter having the drug delivery stent mounted on the balloon.

FIG. 6 is an elevational view of the stent delivery balloon catheter of FIG. 5 after being removed from the mold.

FIG. 7 is a transverse cross sectional view of the stent delivery balloon catheter of FIG. 6, taken along line 7-7.

FIG. 8 illustrates a stent delivery balloon catheter embodying features of the invention, in which the balloon forms shoulders adjacent the ends of the stent.

FIG. 9 illustrates a mold useful in a method of mounting a stent on a balloon catheter, having a stepped inner diameter, to form the shoulders in the balloon.

FIG. 10 illustrates a longitudinal cross sectional view of an alternative embodiment of a stepped inner diameter mold useful in a method of mounting a stent on a balloon catheter, in which end portions of the middle section of the mold have a smaller inner diameter than the portion of middle section therebetween.

FIG. 11 is an isometric view of an alternative mold useful in a method embodying features of the invention, having an insulating non-metal body portion and a metal body portion.

FIG. 12 illustrates a longitudinal cross sectional view of the mold bottom half of FIG. 11, taken along line 12-12.

FIG. 13 is an isometric view of an alternative partially insulating mold useful in a method embodying features of the invention, having a metallic body with insulating non-metal inserts.

Claims

1. A method of mounting a stent on a balloon catheter, comprising: positioning the stent on a balloon of the balloon catheter;applying a first radially compressive force on an outer surface of the stent, thereby decreasing the outer diameter of the stent on the balloon catheter;pressurizing and heating the balloon while restricting radial expansion of the outer surface of the stent; andapplying a second radially compressive force on the outer surface of the stent.

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 stent is a drug delivery stent and mounting the stent on the balloon without damaging the drug delivery layer of the stent, includes 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 ±1 degree to about ±2 degrees F.

4. The method of claim 2, wherein heating the mold includes submerging the mold in a liquid bath.

5. The method of claim 2, wherein heating the mold includes contacting a surface of the mold with a conductive heating element member.

6. The method of claim 2, wherein the mold is a split mold, and further including removing the balloon catheter with the stent mounted thereon from the split mold by opening of the split mold.

7. The method of claim 1, wherein at least one of the radially compressive forces is applied by a crimping apparatus.

8. The method of claim 1, wherein at least one of the radially compressive forces is applied by a hand tool.

9. The method of claim 1, wherein at least one of the radially compressive forces is applied by hand.

10. 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 a first 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 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; andapplying a second radially compressive force on an outer surface of the stent, thereby decreasing the outer diameter of the stent on the balloon catheter.

11. The method of claim 10, further including sterilizing the stent mounted on the balloon catheter.

12. The method of claim 10, wherein at least one of the radially compressive forces is applied by a crimping apparatus.

13. The method of claim 10, wherein at least one of the radially compressive forces is applied by a hand tool.

14. The method of claim 10, wherein at least one of the radially compressive forces is applied by hand.

15. The method of claim 10, wherein the stent is restrained from radially expanding by a mold.

16. The method of claim 15, 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.

17. The method of claim 10, further including sterilization of the balloon catheter and stent with ethylene oxide.

18. A method of increasing retention of an intravascular device on a balloon catheter, comprising: a first stage of crimping the intravascular device onto a balloon of the balloon catheter;a second stage of heating and pressurizing the balloon; anda third stage of re-crimping the intravascular device onto the balloon of the balloon catheter.

19. The method of claim 18, further including heating the intravascular device and the balloon catheter during the third stage.

20. The method of claim 18, further including pressurizing the balloon catheter during the third stage.