Heart valves play an important physiological function of maintaining unidirectional unimpeded forward flow through the heart and from the heart into the major blood vessels connected to the heart, the pulmonary artery and the aorta. However, when natural valves become dysfunctional due to variety of pathological causes, a partial or complete surgical replacement of the natural heart valve with a heart valve prosthesis (artificial heart valves) becomes important. There are three main types of artificial heart valves: the mechanical, the biological, and the tissue engineered valves. The differences between mechanical and biological heart valves are tabulated below:
| Biological Heart Valves | Mechanical Heart Valves |
|---|---|
| Biological valves are valves of animals, like pigs, which undergo several chemical procedures in order to make them suitable for implantation in the human heart. A homograft, or allograft, is a heart valve obtained from a human donor. | A mechanical valve is carefully designed to mimic a native heart valve. There are three major types of mechanical valves – caged-ball, tilting-disk, and bileaflet – with many modifications on these designs. |
| BHVs have a limited lifespan. Traditional tissue valves, made of pig heart valves, will last on average 15 years before they require replacement. | Mechanical heart valves have been traditionally considered to be more durable in comparison to their bioprosthetic counterparts. |
| The primary advantage of tissue (biological) valves is their lower requirement for anticoagulation therapy. | To prevent blood clots from developing on the mechanical valve, anticoagulation medicine (blood thinners) have to be taken daily. The dosage of this medication is different for each person. International normalized ratio (INR) tests measure the time it takes for blood to clot and compares it to an average. |