Heart valves allow the heart to pump blood to specific locations efficiently.
These valves are prone to disease and malfunction, and can be replaced by prosthetic heart valves. The two main types of prosthetic heart valves are mechanical and bioprosthetic. The mechanical valves are excellent in terms of durability, but are hindered by their tendency to coagulate the blood. Bioprosthetic valves are less durable and must be replaced periodically. All valve types must be durable, because the body is an extremely hostile environment for a foreign object, including prosthetic heart valves.