Heart Valve Replacements

Mechanical Heart Valves are prosthetics designed to replicate the function of the natural valves of the human heart. Their main purpose is to prevent regurgitation of blood as it is pumped through the chambers of the heart. Mechanical valves are stressed tested to last 200 years. Current mechanical heart valves all require lifelong treatment with a blood thinner, e.g. warfarin, which requires monthly blood tests to monitor. This process of thinning the blood is called anticoagulation. Mechanical valve can be heard clicking. Patients requiring heart valve replacement often must choose between mechanical and tissue valves.

Tissue Heart Valves are usually made from cow or pig heart valves or pericardial tissue. Animal tissue is treated to prevent rejection and calcification. Tissue valves are quiet and don't require anti-coagulation. Unfortunately all things biological do wear out. A safe figure is that there is an 80% chance the tissue valve will last 15-20 years. Tissue valves may be fabricated from animal tissue (stented valves) or true valve transplants using human or animal valves.

For some patients, a homograft or human aortic heart valve harvested from a cadaver can be implanted. Tissue heart valves do not require the long-term use of anticoagulant medications (blood thinners), due to the improved blood flow dynamics resulting in less red cell damage and, thus, less clot formation. Their drawback, however, is their limited life span. Traditional tissue valves, made of pig heart valves, will last on the average of 15 years before they require replacement.

We are, however, participants in a large national multicenter trial evaluating maintaining the newest generation of mechanical valves without anticoagulation.