[Circulating anticoagulant and open heart surgery (author's transl)].

Two patients presenting an unsettled mitral cardiopathy had to receive a valve replacement under cardiopulmonary by-pass in spite of a circulating anticoagulant with antiprothrombinase activity. A higher risk of thromboembolic trouble required an increase of heparin administration, under a strict biological control. Nevertheless both patients died: the first of coronary thrombosis, the second of cataclysmic bleeding, associated to severe and diffused thrombosis. Thus it is essential to insist upon the risk occurred by those patients and the difficulty of adaptation and control of heparin administration.