Vascular and endoluminal stents with iridium oxide coating

Abstract

A vascular stent adapted to be implanted in a blood vessel of a human patient to enhance the flow of blood therethrough, includes an elongate biocompatible metal member of cylindrical shape and tubular sidewall with a pattern of multiple openings therethrough and open ends. The stent has an insertion outer diameter sufficiently small to enable it to be inserted into and advanced through a portion of the vascular system of the body to a preselected point within a coronary artery. The sidewall has a thin adherent coating of iridium oxide covering substantially its entire exposed surface, including the outward-facing surface between openings, the edges of the openings, the inward-facing surface between openings, and the edge of each of the open ends. The coating is of substantially uniform thickness throughout its coverage of the surface of the sidewall, and serves to reduce irritation of tissue of the inner lining of the vessel wall into which the outward-facing surface of the stent comes into contact. The tissue may project as well into the openings in the sidewall to contact the edges thereof. The iridium oxide coating has a biodegradable carrier of drugs applied thereto for beneficial localized action, as by incorporating into the carrier along the inward-facing surface an anticoagulant drug to reduce attachment of thrombi with blood flow through the lumen of the stent. Although it may be composed of multiple layers, the iridium oxide coating is sufficiently thin and flexible to resist flaking during deployment, and the core member has sufficient rigidity when so deployed to resist collapse.