Traitement antithrombosant au long cours chez les porteurs de prothèses valvulaires: conduite pratique et accidents

: The cumulative annual risk of thrombo-embolic and haemorrhagic complications due to anticoagulants in patients with mechanical prostheses is in the order of 3 to 9 p. cent for mitral prostheses and mitral and aortic prostheses and 2 to 5 p. cent for aortic prostheses. Anticoagulant drugs should be chosen in terms of the type and the site of the implanted prosthesis and the coefficient of the thrombo-embolic and haemorrhagic risk of each subject. In patients with mechanical prostheses, the most effective prevention of the thrombo-embolic risk is ensured by the anti-vitamin K drugs associated with dipyridamole, with a low haemorrhagic risk if the treatment is correctly controlled. In patients with bioprostheses, the anticoagulant treatment (anti-vitamin K or anti-platelet drugs) should be maintained for three to six months after the operation; the anti-vitamin K drugs should not be prolonged indefinitely, except in patients at high risk of thrombo-embolism (atrial fibrillation with a very dilated left auricle, in particular). The management of a pregnant woman with a valve prosthesis and the problems of patients with prostheses undergoing extracardiac or dental operations or invasive investigations are still open to discussion.