Stent delivery system and method using the same

Abstract

Disclosed herein is a stent delivery system which includes: a hollow shaft; first and second expandable balloons arranged around of the distal end of the shaft; and a stent which is arranged around the second balloon such that it expands as the second balloon expands; the first balloon having drug release means for releasing a drug at least to prevent the proliferation of endothelial cells, the stent being a bare metal stent to be indwelled at a target position as lesion of stenosis or occlusion in the lumen of a living body.

1 . A stent delivery system comprising:
 a longitudinally extending hollow shaft;   a first balloon possessing an interior, the first balloon surrounding a distal end portion of the shaft so that the distal end portion of the shaft passes through the first balloon, the first balloon being expandable upon introducing fluid into the interior of the first balloon;   the shaft including a first lumen which opens into the interior of the first balloon to introduce the fluid into the interior of the first balloon to expand the first balloon and cause the first balloon to apply an expansion force to a target site in a lumen of a living body;   a second balloon spaced apart from the first balloon along a longitudinal extent of the shaft, the second balloon possessing an interior, the second balloon surrounding the distal end portion of the shaft so that the distal end portion of the shaft passes through the second balloon, the second balloon being expandable upon introducing fluid into the interior of the second balloon;   the shaft including a second lumen which opens into the interior of the second balloon to introduce the fluid into the interior of the second balloon to expand the second balloon and cause the second balloon to apply an expansion force to the target site in the lumen of the living body;   the first balloon comprising drug release means for releasing a drug which inhibits proliferation of endothelial cells; and   a metal stent surrounding the second balloon and expandable upon expansion of the second balloon so that the stent contacts a surface of the target site in the lumen of the living body, the metal stent being devoid any drug which inhibits proliferation of endothelial cells.   
     
     
         2 . The stent delivery system according to  claim 1 , wherein the first balloon is positioned distally of the second balloon and the stent. 
     
     
         3 . The stent delivery system according to  claim 1 , wherein the first and second balloons both possess a distal end and a proximal end, the distal end of the second balloon being proximally spaced from the proximal end of the first balloon. 
     
     
         4 . The stent delivery system according to  claim 1 , wherein the drug release means is a covering layer surrounding the first balloon, the covering layer containing the drug. 
     
     
         5 . The stent delivery system according to  claim 1 , wherein the drug release means comprises through openings in the first balloon, the through openings communicating with the first lumen. 
     
     
         6 . The stent delivery system according to  claim 1 , further comprising a third expandable balloon arranged around the distal end portion of the shaft and spaced from the first and second balloons along the longitudinal extent of the shaft. 
     
     
         7 . A stent delivery system comprising:
 a hollow shaft;   a first expandable balloon arranged around a distal end portion of the shaft;   a second expandable balloon arranged around the distal end portion of the shaft;   a stent arranged around the second balloon and expandable upon expansion of the second balloon;   the first balloon comprising drug release means for releasing at least a drug which inhibits proliferation of endothelial cells; and   the stent being a bare metal stent to be indwelled at a target position in a lumen of a living body.   
     
     
         8 . The stent delivery system according to  claim 7 , wherein the drug release means is a covering layer of the drug arranged around the first balloon. 
     
     
         9 . The stent delivery system according to  claim 7 , wherein the shaft has a lumen through which the drug is supplied and the drug release means comprises through openings in the first balloon, the through openings communicating with the lumen. 
     
     
         10 . The stent delivery system according to  claim 7 , wherein the first balloon is positioned distally of the stent. 
     
     
         11 . The stent delivery system according to  claim 10 , further comprising a third expandable balloon arranged around the distal end portion of the shaft and axially spaced from the first and second balloons. 
     
     
         12 . The stent delivery system according to  claim 11 , wherein the stent is positioned distally of the third balloon. 
     
     
         13 . The stent delivery system according to  claim 7 , wherein the drug contains sirolimus or paclitaxel. 
     
     
         14 . The stent delivery system according to  claim 13 , wherein the drug contains a drug to cure the lesion part. 
     
     
         15 . The stent delivery system according to  claim 14 , wherein the drug to cure the lesion part is an antihyperlipidemic drug. 
     
     
         16 . A method for placing a stent at a target site in a living body comprising:
 inserting a distal end of a hollow shaft of a stent delivery system into the lumen of a living body, the stent delivery system also comprising first and second axially spaced apart expandable balloons arranged around a distal portion of the shaft, and a stent arranged around the second balloon to expand together with expansion of the second balloon;   moving the shaft to position the first balloon at a target site in the lumen of the living body;   expanding the first balloon;   delivering to the target site a drug which at least inhibits proliferation of endothelial cells, the drug being delivered to the target site by way of the expanded first balloon while the first balloon is positioned at the target site;   collapsing the first balloon;   moving the shaft after collapsing the first balloon to position the stent at the target site at which the drug was delivered;   expanding the second balloon to expand the stent so that the stent comes into contact with a surface of the target site;   collapsing the second balloon; and   withdrawing the shaft, together with the first and second balloons, from the body lumen of the living body while the stent remains in contact with the surface of the target site.   
     
     
         17 . The method according to  claim 16 , wherein the delivering of the drug to the target site involves pressing a covering layer which surrounds the first balloon into contact with the target site, the covering layer being coated with the drug. 
     
     
         18 . The method according to  claim 16 , wherein the delivering of the drug to the target site involves conveying a pressurized fluid into the first balloon and through holes in the first balloon, the pressurized fluid including the drug. 
     
     
         19 . The method according to  claim 16 , wherein the stent delivery system also includes a third expandable balloon around the shaft, and the method further comprising:
 after collapsing the second balloon and before withdrawing the shaft from the body lumen of the living body, moving the shaft to position the third balloon at the target site at which is located the stent; and   expanding the third balloon so that the third balloon contacts the stent and applies an outward expansion force to the stent.   
     
     
         20 . The method according to  claim 16 , wherein the moving of the shaft after collapsing the first balloon comprises moving the shaft distally so that the collapsed first balloon is positioned distally of the target site when the second balloon is expanded to expand the stent into contact with the surface of the target site.