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
substantial 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.