Covered stent having a dissolvable portion

Abstract

An expandable stent having a covering which exhibits the characteristic of upon being activated by applying an agent to the covering, dissolving to expose a portion of the underlying stent. The stent may be placed across the neck of an aneurysm to seal the aneurysm, and thereafter a selected region of the covering may be dissolved by an activating agent to permit blood to flow to adjacent vessels.

1 . An aneurysm treatment device comprising:
 an expandable stent which takes the form of a small diameter skeletal tubular member having a thin wall, said wall of said skeletal tubular member including a plurality of cells which are formed by a plurality of interconnected strut members; and,   a covering extending over a portion of the expandable stent, said covering exhibiting the characteristic of, upon being activated by applying an activating agent to said covering, dissolving to expose a portion of the expandable stent;   wherein the exposed portion of the expandable stent allows fluid flow through the plurality of cells between an interior and exterior of the skeletal tubular member; and   wherein the exposed portion of the stent is exposed to both the interior and exterior of the skeletal tubular member.   
     
     
         2 . An aneurysm treatment device as defined in  claim 1 , wherein the covering is formed of a material which is dissolvable when it comes into contact with an activating agent. 
     
     
         3 . An aneurysm treatment device as defined in  claim 2 , wherein said expandable stent takes the form of a metallic skeletal tubular member and said covering is formed from a polymer. 
     
     
         4 . An aneurysm treatment device as defined in  claim 3 , wherein said covering takes the form of ethylene vinyl alcohol and the activating agent takes the form of dimethylsulfoxide. 
     
     
         5 . An aneurysm treatment device as defined in  claim 4 , wherein the covering takes the form of a thin film of ethylene vinyl alcohol disposed on an outer surface of said expandable stent. 
     
     
         6 . An aneurysm treatment device comprising:
 an expandable tubular member having a thin wall, said wall of said tubular member is formed of a material exhibiting the characteristic that when an activating agent is applied to a portion of the wall of said tubular member said portion of the wall dissolves to provide a passageway through the wall.   
     
     
         7 . An aneurysm treatment device as defined in  claim 6 , wherein the wall of said expandable tubular member takes the form of ethylene vinyl alcohol and the activating agent takes the form of dimethylsulfoxide. 
     
     
         8 . An aneurysm treatment device as defined in  claim 7 , wherein said expandable tubular member takes the form of a thin film of ethylene vinyl alcohol. 
     
     
         9 . An aneurysm treatment device as defined in  claim 1 , wherein said covering extends the entire longitudinal length of the stent.