| abstract |
There is provided medical devices for use as cardiac, coronary or vascular prostheses, for example heart valves, coronary artery bypass grafts and arterial grafts. The devices described are at least partially coated or impregnated with a hydrophilic polymer composition which desirably contains of from 1 to 99 % by weight of water, preferably 50 to 95 % by weight of water. The hydrophilic polymer composition may be biodegradable and preferably contains a polyurethane. Optionally the hydrophilic polymer composition may contain a pharmaceutically active agent, for example an anti-coagulant, a thrombolytic agent or an antibiotic. The device may be treated with two or more hydrophilic polymer compositions in separate coatings; a triple-layered coating may be especially beneficial. The presence of the hydrophilic polymer coating is beneficial in reducing the thrombogenesis which may occur following implantation of the device |