| abstract |
A vascular or endoluminal stent is adapted to be implanted in a vessel, duct or tract of a human body to maintain an open lumen at the site of the implant. The sidewall of the open-ended tubular structure of the stent is a base layer of a metal biologically compatible with blood and tissue of the human body. An intermediate metal particle layer of substantially greater radiopacity overlies the base layer, with particles bonded to the base layer and to each other to leave interstices therebetween as a repository for retaining and dispensing drugs or other agents for time release therefrom after the stent is implanted, to assist the stent in maintaining the lumen open. The particles are composed primarily of a noble metal—an alloy of platinum-iridium. The sidewall has holes extending therethrough, and the particle layer resides along the outward facing and inward facing surfaces, and the edges of the through holes and open ends of the sidewall. The larger particles are bonded to surfaces of the sidewall and progressively smaller particles are bonded to those and to each other up to the outer portion of the particle layer. Exposed surfaces of the particle layer are coated with ceramic-like iridium oxide or titanium nitrate, as a biocompatible material to inhibit irritation of tissue at the inner lining of the vessel when the stent is implanted. One or more anti-thrombotic, anti-platelet, anti-inflammatory and/or anti-proliferative drugs are retained in the interstices, together with a biodegradable carrier for time release therefrom. In an alternative embodiment, the intermediate layer is solid and the biodegradable carrier and drugs or agents therein are applied to the surface of the ceramic-like coating. Gene transfer is alternatively used to control tissue proliferation. |