[Hemorrhagic complications of anticoagulants in angiology].

Anticoagulants (unfractionated heparin UFH, low-molecular-weight heparins LMWH, coumarins) are mainly used to prevent (prophylactic dosage) or treat (therapeutic dosage) deep-vein thrombosis and pulmonary embolism. After surgery, prophylactic regimens of UFH and LMWH induce a doubling of the hemorrhagic risk which is observed under placebo. At therapeutic dosages, UFH and LMWH are associated with a risk of major bleeding of about 5%, with a trend favouring LMWH for a similar antithrombotic efficacy. At therapeutic levels, coumarins induce major bleeding at a rate of approximately 1%/month. This figure is proportional to the duration and the intensity (INR) of the treatment. It appears to be the major determinant of an optimal duration of anticoagulant treatment following deep-vein thrombosis.