Variable flexibility stent

Abstract

A stent is provided for having variable flexibility and stiffness along its length. The stent comprises portions of the stent having different bending and durability characteristics, and may be fabricated, using any of a variety of methods, out of any of a variety of materials.

What is claimed is:  
     
         1 . A stent having variable bending flexibility across its length.  
     
     
         2 . The stent of    claim 1   , wherein the stent is comprised of component members having variable dimensions to vary the stiffness of the stent in the longitudinal direction.  
     
     
         3 . The stent of    claim 1   , wherein the stent is comprised of component members having variable composition to vary the stiffness of the stent in the longitudinal direction.  
     
     
         4 . The stent of    claim 1   , wherein the stent is relatively less rigid for bending at its ends and relatively more rigid for bending in its center.  
     
     
         5 . The stent of    claim 1   , which is comprised of a mesh.  
     
     
         6 . The stent of    claim 1   , which is comprised of a spiral coil.  
     
     
         7 . The stent of    claim 1   , which is fabricated out of a material selected from the group comprising stainless steel, nitinol, titanium, tantalum, and other metals and metal alloys.  
     
     
         8 . The stent of    claim 1   , which has been fabricated by a method selected from the group comprising forming, stamping and etching.  
     
     
         9 . The stent of    claim 1   , which has been fabricated using a film contact imaging method.  
     
     
         10 . The stent of    claim 1   , which has been fabricated using a laser cutting method.  
     
     
         11 . A stent having variable flexibility across its length, which comprises a tubular member consisting essentially of annular members intended to expand and cross member having ends, the end of each cross member being attached to an annular member, 
 wherein the cross members have differing rigidity for bending such that the stent has variable flexibility along its length.    
     
     
         12 . A stent comprising a plurality of expandable annular members; and a plurality of cross members having ends, the ends of each cross member being attached to an expandable annular member at a point in common with a longitudinally adjacent cross member; the expandable annular members differing in their relative rigidity and positioned so as to vary the bending flexibility of the stent along its length.  
     
     
         13 . The stent of    claim 12    comprising a plurality of dimensionally variable members.  
     
     
         14 . The stent of    claim 12    comprising a plurality of compositionally variable members.  
     
     
         15 . The stent of    claim 12   , wherein the expandable annular members positioned at the ends of the stent are less rigid than the expandable annular members positioned at the center of the stent, such that the bending flexibility of the stent is greater at the ends of the stent than in the middle of the stent.  
     
     
         16 . The stent of    claim 12    fabricated from at least one material selected from the group consisting of stainless steel, nitinol, titanium, tantalum, and other metals and metal alloys.  
     
     
         17 . The stent of    claim 12   , which has been fabricated using a method selected from the group consisting of forming, stamping, and etching.  
     
     
         18 . The stent of    claim 12   , which has been fabricated using a film contact imaging method.  
     
     
         19 . The stent of    claim 12   , which has been fabricated using a laser cutting method.  
     
     
         20 . The stent of    claim 12   , wherein both the expandable annular members and the cross members differ in their relative rigidities.  
     
     
         21 . The stent of    claim 12    comprising a plurality of distal ends and a middle portion, wherein the bending flexibility of the stent is greater at the distal ends than at the middle portion.