Artificial heart valve

An artificial heart valve is a device which is implanted in the heart of patients who suffer from valvular diseases in their heart. When one or two of the four heart valvesof the heart have a malfunction, the choice is normally to replace the natural valve by an artificial valve. This requires Open-Heart Surgery.

There are two types of artificial heart valves: the mechanical and the biological valves.

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The mechanical valves are made of a metal ring covered by a tissue, into which the suturethreads are stitched, in order to keep the valve in place once implanted. The metal ring holds, by means of two metal supports, a disc which opens and closes as the heart pumps blood through the valve. The disc is usually made of an extremely hard carbon material (pyrolitic carbon), in order to allow the valve to function during years without wearing out. In some models of mechanical valves, the disc is divided into two parts, which open and close as a door.

Mechanical heart valves are today very reliable and allow the patients to live a normal life. One of the main advantages of these valves is that they are well tolerated by the body. Only a small amount of blood thinner is needed to be taken by the patient each day, in order to prevent clotting of the blood when flowing through the valve.

The 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. Although these valves, being of natural origin, are the best choice from the standpoint of blood flow, they show a certain failure rate, either due to reactions by the patient's body or to deteriorations of the valve tissue.

For this reason, a major part of the artificial valves which are implanted are mechanical valves.

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It uses material from the http://en.wikipedia.org/wiki/Artificial+heart+valve Wikipedia article Artificial heart valve.