Prolonged prophylaxis against postoperative venous thromboembolism.

This review deals with the problem of delayed thrombosis and thereby the potential need of prolonged prophylaxis. The risk of late thrombosis and pulmonary embolism is discussed from pathogenetic factors and data on frequencies of thromboembolic complications in the literature. The problems concerning long term or prolonged prophylaxis are indicated and studies on prolonged prophylaxis-our own included-are analyzed. There is an urgent need to define which risk factors motivate prolonging thromboprophylaxis for more than the standard 7-14 days.