The treatment of venous thromboembolism.

Venous thromboembolism is usually treated with heparin followed by oral anticoagulants for approximately 3 months. The optimal length of heparin therapy is uncertain. There is now good evidence that treatment failures are associated with inadequate heparin effects. Heparin can be administered with similar safety and effectiveness by either intravenous infusion or 2 hourly subcutaneous injection. Oral anticoagulant therapy is effective and safe if given in a dose which prolongs the prothrombin time to an international normalized ratio of 2.0 to 2.5. Thrombolytic therapy is indicated in patients with major pulmonary embolism and in selected patients with recent acute venous thrombosis. Vena caval interruption is usually confined to patients who have contraindications to anticoagulant therapy. Surgical removal of thromboembolic obstruction should be considered in selected patients with thromboembolic pulmonary hypertension.