[Anticoagulation in mechanical valve prostheses. A difficult situation]

Although long-term anticoagulant therapy in patients with mechanical valve prostheses is well codified, a number of difficult situations persists because of the high thromboembolic risk. The protocols of anticoagulation suggested in these situations are controversial as there are no large scale prospective therapeutic trials. However, modern protocols take more and more into account the thromboembolic risk in each individual case. The authors review the most common situations: the early postoperative period for which no precise consensus exists in the literature; anticoagulation in extra-cardiac surgery, a common situation for which the protocols remain very debatable; anticoagulation in pregnancy, a special situation because of the risk of embryopathy with oral anticoagulant therapy and the risk of thromboembolism with heparin; anticoagulation in cases of thromboembolic complications; anticoagulation during infectious endocarditis; anticoagulation during serious haemorrhage.