Multilayer stent

Abstract

A composite stent having a substrate tube made of stainless steel, a nickel-cobalt-chromium-molybdenum alloy, or chonichrome with at least one metal cladding tube is disclosed. Specifically, the substrate tube is placed within a metal cladding tube made of platinum, gold, tantalum, tungsten, platinum-iridium, palladium, or nickel-titanium, preferably with an interference fit therebetween. The composite, laminate tube then undergoes a series of rolling or cold drawing processes interspersed with heat treating to release built up stresses. When the final diameter of the laminate tube is reached, the cladding has been laminated to the exterior of the substrate tube by a bond generated from the rolling and/or cold drawing operations. The finished laminate tube is then cut by laser cutting or chemical etching to form a suitable stent pattern.

1 - 38 . (canceled) 
   
   
       39 . A laminate stent for implantation within a body lumen, comprising:
 a substrate tube formed from a superelastic alloy and having an exterior surface;   a first cladding layer formed from a metallic radiopaque material and bonded to the exterior surface of the substrate tube;   a second metallic cladding layer comprising a NiTi alloy bonded to the first layer thereby forming a laminate tube; and   a stent pattern formed in the laminate tube such that the resultant laminate stent includes a plurality of radially expandable cylindrical elements disposed generally coaxially and interconnected by elements disposed between adjacent cylindrical elements, the cylindrical elements and the interconnecting elements being entirely formed of the substrate tube, the first radiopaque cladding layer, and the second metallic cladding layer.   
   
   
       40 . The laminate stent of  claim 39 , wherein the superelastic alloy of the substrate tube comprises NiTi. 
   
   
       41 . The laminate stent of  claim 39 , wherein the wall thickness of the second metallic cladding layer is less than the wall thickness of the metallic substrate tube. 
   
   
       42 . The laminate stent of  claim 39 , wherein the substrate tube has a coefficient of thermal expansion that is less than a coefficient of thermal expansion of the first radiopaque cladding layer. 
   
   
       43 . The laminate stent of  claim 39 , wherein the radiopaque material in the first cladding layer is a metal selected from the group consisting of platinum, gold, tantalum, tungsten, a platinum-iridium alloy, and palladium. 
   
   
       44 . The laminate stent of  claim 43 , wherein the radiopaque material in the first cladding layer is a platinum-10% iridium alloy. 
   
   
       45 . The laminate stent of  claim 39 , wherein the radiopaque material in the first cladding layer is selected from the group consisting of platinum, gold, tantalum, tungsten, a platinum-iridium alloy, and palladium. 
   
   
       46 . The laminate stent of  claim 39 , wherein the laminate stent has an unexpanded diameter of up to about 0.1 inches. 
   
   
       47 . The laminate stent of  claim 46 , wherein the laminate stent has an unexpanded diameter ranging from about 0.05 inches to about 0.07 inches. 
   
   
       48 . The laminate stent of  claim 39 , wherein the laminate stent has an expanded diameter ranging from about 0.06 inches to about 0.3 inches. 
   
   
       49 . The laminate stent of  claim 48 , wherein the laminate stent has an expanded diameter ranging from about 0.1 inches to about 0.2 inches. 
   
   
       50 . The laminate stent of  claim 39 , wherein the laminate stent has a length ranging from about 10 to 50 mm. 
   
   
       51 . The laminate stent of  claim 50 , wherein the laminate stent has a length ranging from about 15 to 25 mm. 
   
   
       52 . The laminate stent of  claim 39 , wherein each of the plurality of radially expandable cylindrical elements is independently expandable. 
   
   
       53 . The laminate stent of  claim 39 , wherein the substrate tube, the first cladding layer, and the second cladding layer are bonded by rolling and cold drawing. 
   
   
       54 . The laminate stent of  claim 39 , wherein the substrate tube, the first cladding layer, and the second cladding layer have been heat treated. 
   
   
       55 . The laminate stent of  claim 39 , wherein the stent pattern is formed by a process selected from the group consisting of chemical etching and laser cutting.