Why is an anticoagulant required when an artificial valve is implanted?
Artificial valve material is thrombogenic. Clots can form on the valve and obstruct it. Fragments of clot can detach from the valve and get lodged in different parts of the blood stream and block other blood vessels. For these reasons, it is mandatory to take coumadin or a similar anticoagulant lifelong for mechanical artificial valves. Bioprosthetic valves need anticoagulation only for a short period of about 3 months. Hence bioprosthetic valves are preferred in the elderly where the bleeding risk of long term anticoagulants is presumed to be high and degeneration of bioprosthetic valves lesser.