[Valvular prosthesis: indications and updated protocols for thrombosis prophylaxis].

Anticoagulants of the dicumarol group are the antithrombotic drugs more widely employed in patients with prosthetic valves: they have demonstrated a favorable activity in the protection from the thromboembolic complications, which depend on the lack of biocompatibility between the valvar surfaces and the blood. The lack of biocompatibility is temporary in the biological valves, while is permanent in the mechanical, therefore requiring an anticoagulation lasting all the life. The treatment, on the other hand, can induce side effects, of which the most severe is the possibility of hemorrhagic complications, seldom very severe or leading to death. The way the patients are treated and the precision of the laboratory control, as the INR test, have proved to be the most important factors affecting the fate of the valves and of the patients. With a well conducted laboratory control a pregnancy has proved possible in female patients with a mechanical valve, judiciously alternating heparin, antivitamin K drugs and again heparin during pregnancy.