Custom-length self-expanding stent delivery systems with stent bumpers

Abstract

Custom-length self-expanding stent delivery systems and methods enable precise control of prosthesis position during deployment. The stent delivery systems carry multiple stent segments and include a stent bumper for helping control the axial position of the stent segments during deployment. This enables the deployment of multiple prostheses at a target site with precision and predictability, preventing stent segment recoil and ejection from the delivery device and thus eliminating excessive spacing or overlap between prostheses. In particular embodiments, the prostheses of the invention are deployed in stenotic lesions in coronary or peripheral arteries or in other vascular locations.

1 . A catheter system for delivery of a stent to a body lumen comprising: 
 a stent delivery catheter comprising: 
 a sheath having a first lumen;  
 a shaft extending through the first lumen and slidable relative to the sheath;  
 a stent bumper mounted to the shaft distally of the sheath and movable from a contracted shape to an expanded shape; and  
   a plurality of self-expanding stent segments carried within the first lumen in a collapsed configuration, the stent segments being adapted to resiliently expand from the collapsed configuration to an expanded configuration, and    wherein the stent segments are deployable from the first lumen so as to resiliently expand into the expanded configuration, the stent bumper being expandable independently of the stent segments and configured in the expanded shape to engage a first stent segment during deployment thereof to maintain its position relative to an adjacent stent segment disposed proximal to the first stent segment, and    wherein the sheath is disposed over the balloon and the sheath is retractable to expose a portion of the stent bumper to allow it to expand from the contracted shape to the expanded shape.    
   
   
       2 . A system as in  claim 1 , wherein the stent bumper in the expanded shape has an outer diameter sized to contact an inner wall of the body lumen.  
   
   
       3 . A system as in  claim 1 , wherein the stent bumper in the expanded shape has an outer diameter sized to contact an inner wall of at least one of the expanded stents.  
   
   
       4 . A system as in  claim 1 , wherein the stent bumper comprises an inflatable balloon.  
   
   
       5 . A system as in  claim 4 , wherein the balloon is adapted to be deflated, positioned within the deployed first stent segment, and re-inflated to the expanded shape.  
   
   
       6 . A system as in  claim 5 , wherein the balloon in the expanded shape is adapted to further expand the deployed first stent segment.  
   
   
       7 . A system as in  claim 1 , wherein the axial length of the elongate balloon is between 20 mm and 250 mm.  
   
   
       8 . A system as in  claim 1 , wherein each of the stent segments has a length of between 3 mm and 30 mm.  
   
   
       9 . A system as in  claim 1 , wherein the plurality of stent segments comprises between 2 and 50 segments.  
   
   
       10 . A system as in  claim 1 , further comprising a pusher slidably disposed over the shaft, proximal to the stent segments, for advancing the stent segments relative to the sheath or holding the stent segments in place while the sheath is retracted.  
   
   
       11 . A system as in  claim 1 , wherein the stent bumper is adapted to be moved to the expanded shape while at least a portion of the stent segments remain in the collapsed configuration.  
   
   
       12 . A system as in  claim 1 , wherein the stent bumper engages the first stent segment as it expands thereby maintaining position of the first stent segment relative to the sheath.  
   
   
       13 . A system as in  claim 1 , wherein two or more stent segments are deployed sequentially without repositioning the delivery catheter relative to the body lumen.  
   
   
       14 . A system as in  claim 1 , wherein the stent bumper maintains the position of each stent segment during deployment such that adjacent stent segments do not overlap and a spacing between adjacent stent segments is no more than about 1 mm after deployment.  
   
   
       15 . A method of delivering a stent to a body lumen comprising: 
 positioning a stent delivery catheter in the body lumen, the delivery catheter carrying at least first and second stent segments;    expanding a stent bumper on the delivery catheter;    releasing the first stent segment from the delivery catheter into the body lumen after the stent bumper has been fully expanded, the first stent segment resiliently self-expanding into an expanded configuration in the body lumen, wherein the stent bumper expands independently of the first stent segment and engages the first stent segment during expansion thereof to maintain its position relative to the delivery catheter;    before releasing the second stent segment, contracting the stent bumper;    positioning the contracted stent bumper within the expanded first stent segment;    re-expanding the stent bumper, wherein the stent bumper engages the second stent segment during expansion thereof to maintain its position relative to the delivery catheter and the first segment; and    releasing the second stent segment from the delivery catheter into the body lumen adjacent to the first stent segment,    wherein the stent bumper maintains the position of each stent segment during deployment such that adjacent stent segments do not overlap and a spacing between adjacent stent segments is no more than about 1 mm after deployment.    
   
   
       16 . A method as in  claim 15 , wherein expanding the stent bumper comprises inflating a balloon.  
   
   
       17 . A method as in  claim 16 , further comprising, before inflating the balloon, exposing a portion of the balloon from the distal end of an inner sheath disposed over the balloon.  
   
   
       18 . A method as in  claim 15 , wherein releasing each stent segment comprises: 
 maintaining an axial position of the stent segments relative to the delivery catheter using a pusher member of the catheter; and    retracting an outer sheath disposed over the stent segments.    
   
   
       19 . A method as in  claim 15 , wherein releasing each stent segment comprises: 
 maintaining an axial position of an outer sheath disposed over the stent segments relative to the delivery catheter; and    advancing the stent segments out of a distal end of the sheath using a pusher member of the catheter.    
   
   
       20 . A method as in  claim 15 , wherein the first and second stent segments are released sequentially without repositioning the delivery catheter relative to the body lumen.