Method of stent mounting to form a balloon catheter having improved retention of a drug delivery stent

Abstract

A method of mounting a drug delivery stent on a balloon of a balloon catheter. The method securely mounts the drug delivery stent on the balloon without damaging the drug delivery layer of the stent. In one embodiment, the method generally comprises positioning a drug delivery 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, to mount the stent on the balloon without damaging the drug delivery layer of the stent.

1 - 18 . (canceled) 
   
   
       19 . An assembly for mounting a drug-delivery stent on a balloon of a balloon catheter, comprising:
 a) a mold having a body formed at least in part of a metallic material and defining a polished bore configured to receive a balloon of a balloon catheter having a drug-delivery stent on the balloon; and   b) a heat transfer medium which is configured to contact the mold and thereby heat the mold and the balloon within the mold, and which provides temperature control to the mold with a tolerance of about ±1 degree to about ±2 degrees F.   
   
   
       20 . The assembly of  claim 19  wherein the heat transfer medium has a relatively high thermal conductivity higher than that of air, and is a metal platen with a surface configured to press against an outer surface of the mold to thereby heat the mold. 
   
   
       21 . The assembly of  claim 19  wherein the heat transfer medium has a relatively high thermal conductivity higher than that of air, and is a hot liquid bath, and the mold includes sealing members which seal around the balloon catheter within the mold to thereby prevent the liquid bath from contacting the balloon within the mold. 
   
   
       22 . The assembly of  claim 19  wherein the bore is defined by a polished inner surface having a polish finish equal to or smaller than about 0.4 microns. 
   
   
       23 . The assembly of  claim 19  wherein the mold is split-mold with hinged halves. 
   
   
       24 . The assembly of  claim 19  wherein the mold bore has a stepped inner diameter comprising enlarged inner diameter sections on either end of a middle section, configured to form shoulders in the balloon adjacent ends of the stent with an outer diameter greater than an outer diameter of the unexpanded stent mounted on the balloon. 
   
   
       25 . The assembly of  claim 19  wherein the mold has a metallic body defining the bore and an outer surface of the mold, so that heating the mold substantially uniformly heats the entire length of the balloon within the bore of the mold. 
   
   
       26 . The assembly of  claim 19  wherein the mold has a body with a heat conducting metallic section, and an insulating non-metal section defining a region of the bore configured to receive the drug delivery stent, so that heating the mold selectively heats sections of the balloon within the bore of the mold. 
   
   
       27 . A balloon catheter having a drug delivery stent releasably mounted thereon, comprising:
 a) an elongated shaft having a proximal end, a distal end, and an inflation lumen;   b) a balloon sealingly secured to a distal shaft section with an interior in fluid communication with the inflation lumen, which inflates from a noninflated configuration to an inflated configuration; and   c) a drug-delivery stent having a drug delivery layer and an open-walled body of stent struts with gaps between adjacent stent struts, mounted on the noninflated balloon so that the stent is embedded in an outer surface of the noninflated balloon with the drug delivery layer having a uniform thickness and defining an outer surface of the embedded stent.   
   
   
       28 . The stent delivery balloon catheter of  claim 27  wherein the balloon has a shoulder adjacent an end of the mounted stent with an outer diameter greater than an outer diameter of the mounted stent in an unexpanded configuration. 
   
   
       29 - 30 . (canceled)