Bioabsorbable Polymer, Non-Bioabsorbable Metal Composite Stents

Abstract

Biocompatible materials may be configured into any number of implantable medical devices including intraluminal stents. The biocompatible material may comprise metallic and non-metallic materials in hybrid structures. In one such structure, a device may be fabricated with one or more elements having an inner metallic core that is not degradable with an outer shell formed from a polymeric material that is biodegradable. Additionally, therapeutic agents may be incorporated into the microstructure or the bulk material.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to implantable medical devices, and more particularly, to implantable medical devices fabricated as composite structures.[0003]2. Discussion of the Related Art[0004]Currently manufactured intravascular stents do not adequately provide sufficient tailoring of the microstructural properties of the material forming the stent to the desired mechanical behavior of the device under clinically relevant in-vivo loading conditions. Any intravascular device should preferably exhibit certain characteristics, including maintaining vessel patency through a chronic outward force that will help to remodel the vessel to its intended luminal diameter, preventing excessive radial recoil upon deployment, exhibiting sufficient fatigue resistance and exhibiting sufficient ductility so as to provide adequate coverage over the full range of intended expansion diameters.[0005]Accordingly, there is a need to develo...

AI Technical Summary

Benefits of technology

[0009]The biocompatible materials for implantable medical devices of the present invention offer a number of advantages over currently utilized materials. The biocompatible materials of the present invention are magnetic resonance imaging compatible, are less brittle than other metallic materials, have enhanced ductility and toughness, and have increased durability. The biocompatible materials also maintain the desired or beneficial characteristics of currently available metallic materials, including strength and flexibility.

[0011]The biocompatible materials of the present invention are simple and inexpensive to manufacture. The biocompatible materials may be formed into any number of structures or devices. The biocompatible materials may be thermomechanically processed, including cold-working and heat treating, to achieve varying degrees of strength and ductility. The biocompatible materials of the present invention may be age hardened to precipitate one or more secondary phases.

[0012]The biocompatible materials of the present invention comprise a unique composition and designed-in properties that enable the fabrication of stents that are able to withstand a broader range of loading conditions than currently available stents. More particularly, the microstructure designed into the biocompatible materials facilitates the design of stents with a wide range of geometries that are adaptable to various loading conditions.

Problems solved by technology

Currently manufactured intravascular stents do not adequately provide sufficient tailoring of the microstructural properties of the material forming the stent to the desired mechanical behavior of the device under clinically relevant in-vivo loading conditions.

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