Implantable medical device constraint and deployment apparatus

Abstract

An implantable device delivery system is disclosed. The delivery system includes a constraining member situated between an interior layer and an exterior layer of a cover. The interior layer of the cover is disposed about an implantable medical device, and the exterior layer of the cover extends over a portion of the interior layer. The cover is generally tapered to minimize deployment forces. The constraining member is disposed about a portion of the interior layer and operates to constrain the implantable device to a delivery configuration. The cover and the constraining member are generally configured to be removed concurrently during deployment of the implantable device.

What is claimed is: 
     
         1 . A medical system comprising:
 an expandable endoprosthesis having a proximal end and a distal end;   an elongate member having a proximal end and a distal end, the expandable endoprosthesis being situated along the elongate member proximate the distal end of the elongate member;   a cover having a first end and a second end, the cover including a first portion and a second portion, the first portion being disposed about the expandable endoprosthesis and the second portion extending over at least part of the first portion;   a constraining member disposed about the expandable endoprosthesis such that the constraining member is situated between the first and second portions of the tubular cover, the constraining member constraining the expandable endoprosthesis in a delivery configuration; and   a distal step element positioned about the elongate member and projecting radially therefrom.   
     
     
         2 . The medical system of  claim 1 , wherein the distal step element is annular shaped. 
     
     
         3 . The medical system of  claim 1 , wherein the distal step element includes a body having an exterior surface, a distal end, and a proximal end. 
     
     
         4 . The medical system of  claim 3 , wherein the body of the distal step element includes a lumen defined therethrough, the lumen capable of being positioned about the elongate member. 
     
     
         5 . The medical system of  claim 1 , wherein the distal step element is positioned distal to the distal end of the expandable endoprosthesis. 
     
     
         6 . The medical system of  claim 5 , wherein the distal step element abuts the distal end of the expandable endoprosthesis. 
     
     
         7 . The medical system of  claim 1 , wherein expandable prosthesis overlays at least a portion of the distal step element. 
     
     
         8 . The medical system of  claim 1 , further comprising a proximal support element positioned about the elongate member at a position proximal to the expandable prosthesis. 
     
     
         9 . A medical system comprising:
 an expandable endoprosthesis having a proximal end and a distal end;   an elongate member having a proximal end and a distal end, the expandable endoprosthesis being situated along the elongate member proximate the distal end of the elongate member;   a cover having a first end and a second end, the cover including a first portion and a second portion, the first portion being disposed about the expandable endoprosthesis and the second portion extending over at least part of the first portion;   a constraining member disposed about the expandable endoprosthesis such that the constraining member is situated between the first and second portions of the tubular cover, the constraining member constraining the expandable endoprosthesis in a delivery configuration; and   a proximal support element positioned about the elongate member and projecting radially therefrom.   
     
     
         10 . The medical system of  claim 9 , wherein the proximal support element includes a body having a distal end, a proximal end, a first exterior surface, and a second exterior surface, the first and second exterior surfaces being coaxial with the elongate member. 
     
     
         11 . The medical system of  claim 10 , wherein the body of the proximal support element includes a lumen defined therethrough, the lumen capable of being positioned about the elongate member. 
     
     
         12 . The medical system of  claim 10 , wherein the first and second exterior surfaces have different diameters. 
     
     
         13 . The medical system of  claim 9 , wherein the proximal support element is positioned proximal to the proximal end of the expandable endoprosthesis. 
     
     
         14 . The medical system of  claim 13 , wherein the proximal support element abuts the proximal end of the expandable endoprosthesis. 
     
     
         15 . The medical system of  claim 9 , wherein the cover extends to a position along the elongate element proximal to the proximal end of the proximal support element. 
     
     
         16 . The medical system of  claim 9 , wherein the cover is coupled to the proximal support element. 
     
     
         17 . The medical system of  claim 9 , further comprising a distal step element positioned about the elongate member and projecting radially therefrom. 
     
     
         18 . The medical system of  claim 9 , further comprising an intermediate support element positioned about the elongate member at a position radially inward relative to the expandable prosthesis. 
     
     
         19 . A medical system comprising:
 an expandable endoprosthesis having a proximal end and a distal end;   an elongate member having a proximal end and a distal end, the expandable endoprosthesis being situated along the elongate member proximate the distal end of the elongate member;   a cover having a first end and a second end, the cover including a first portion and a second portion, the first portion being disposed about the expandable endoprosthesis and the second portion extending over at least part of the first portion;   a constraining member disposed about the expandable endoprosthesis such that the constraining member is situated between the first and second portions of the tubular cover, the constraining member constraining the expandable endoprosthesis in a delivery configuration; and   an intermediate support element positioned about the elongate member at a position radially inward relative to the expandable prosthesis.   
     
     
         20 . The medical system of  claim 19 , wherein the intermediate support element includes a compliant material into which the expandable endoprosthesis at least partially embeds in a delivery configuration.