The optimal duration of secondary thromboprophylaxis in patients with venous thromboembolism The importance of thrombophilia screening

Venous thromboembolism is a chronic disease with an annual incidence of recurrence of 5 to 10 %. Patients with venous thrombosis should be treated with anticoagulants for at least 3 months. The optimal duration of anticoagulation entails balancing the risk of recurrence against the risk of treatment-associated bleeding. Candidates for extended anticoagulation are patients with a high risk of recurrence. The risk of recurrence is increased in patients with antithrombin deficiency, the lupus anticoagulant, homozygous F V Leiden, combined defects, high F VIII, high F IX, high TAFI, hyperhomocysteinemia or more than one episode of thrombosis. The risk of recurrence is low in patients with venous thrombosis secondary to surgery or trauma. Routine thrombophilia screening is aimed at identifying patients who could benefit from extended anticoagulation. This population consists of patients with venous thrombosis at a young age, an unprovoked episode of venous thrombosis, patients with a strong positive family history or patients with recurrent venous thrombosis. Screening should comprise antithrombin determination and the search for the lupus anticoagulant. Patients harbouring one of these defects are at high risk of recurrence and most likely will profit from prolonged anticoagulation. The clinical relevance of new treatment strategies such as extended low-intensity warfarin or administration of the direct thrombin inhibitor (xi-)melagatran is at present unclear.