[Prevention of recurrence of thromboembolic disease: maintenance of anticoagulant therapy].

Deep venous thrombosis and pulmonary embolism are frequently diagnosed in patients encountered in a primary-care practice. Poor prognosis is related to acute sudden death and to recurrent thromboembolic disease. Anticoagulant therapy with heparin followed by coumarin derivatives is highly effective in preventing such recurrences, but the intensity of anticoagulation must be strictly monitored. Treatment with heparin, sufficient to prolong the activated partial prothrombin time to 1.5 to 2.0 times the control, should be continued for five to ten days, and oral anticoagulation should be overlapped with heparin for four to five days. The recommended therapeutic range for the prothrombin time during coumarin therapy is an INR of 2.0 to 3.0. The duration of anticoagulant treatment must be tailored to the individual patient. Patients with slowly resolving risk factors must be treated for at least three months after an acute deep vein thrombosis and for six months after a pulmonary embolism. Patients with tumors, antithrombin III, protein C or S deficiency should be treated indefinitely.