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.

Description

RELATED APPLICATIONS[0001]This is a divisional application of co-pending parent application having U.S. Ser. No. 09 / 270,403, filed Mar. 16, 1999, the contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]The present invention relates to expandable intraluminal vascular devices, generally referred to as stents. More precisely, the present invention is directed to stents that have a metallic cladding for improved expansion characteristics and radiopacity.[0003]Stents are used to maintain patency of vessels in the body, such as a patient's arteries. A variety of delivery systems have been devised that facilitate the placement and deployment of stents. The stent is initially manipulated while in its contracted or unexpanded state, wherein its reduced diameter more readily allows it to be introduced into the body lumen, such as a coronary artery, and maneuvered into the target site where a lesion has been dilated. Once at the target site, the stent is ex...

AI Technical Summary

Benefits of technology

The present invention is a stent that has a metallic substrate and at least one layer of metallic cladding. The cladding is joined to the substrate under high pressure, resulting in a strong bond that resists separation or delamination. The stent has good strength, ductility, and radiopacity, which are important properties for stent design and performance. The method of fabricating the stent involves disposing a first cladding tube about the substrate tube and joining it to the substrate tube. A second cladding tube can also be added to further enhance the stent's properties. The use of a substrate or cladding tube made from a shape memory alloy, such as nickel-titanium, can also provide the stent with superelastic properties, reducing the need for higher pressure balloons and minimizing injury to the vessel walls.

Problems solved by technology

But stents can sometimes cause complications including thrombosis, and neointimal hyperplasia by inducement of smooth muscle cell proliferation at the site of implantation of the stent.

Such stents typically also do not provide for delivery of localized therapeutic pharmacological treatment of a blood vessel at the location being treated with the stent, which can be useful for overcoming such problems.

Despite progress in the art, there is presently no stent available that has a metallic cladding for improved strength reinforcement, expansion characteristics and radiopacity.

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