Anticoagulants lengthen the time it takes for blood to clot.
Clotting is a normal property of blood. At times clotting can cause problems for people with certain types of artificial heart valves. Your diseased heart valve has been replaced by a mechanical valve. People with mechanical valves are at risk for developing small blood clots on the valves. To prevent clots from forming, your doctor has prescribed an anticoagulant called Coumadin.