Venous Thromboembolism Risk Factors for Recurrence

Patients who have a first episode of venous thromboembolism (VTE) have an elevated risk of a recurrent episode, and this necessitates secondary prophylaxis. Anticoagulant therapy is a double-edged sword, however, as it reduces the risk of recurrent VTE but increases the risk of hemorrhage. This balance must be taken into account when assessing the risk-benefit ratio of long-term anticoagulation. Some clinical characteristics of the index VTE event can help to categorize the individual risk of recurrence. Patients with persistent risk factors such as cancer have a significantly higher risk of recurrent thrombosis. In contrast, VTE provoked by transient risk factors is associated with a lower risk of recurrence. Intrinsic features of patients with VTE (gender, age, hereditary thrombophilia) have also been linked to the risk of recurrent VTE. There is increasing evidence that a normal D-dimer level and the absence of residual venous thrombosis after discontinuation of oral anticoagulation are associated with a lower risk of recurrent VTE events. Future studies are needed to refine the predictive value of known risk factors for VTE recurrence and to discover better markers. (Arterioscler Thromb Vasc Biol. 2009;29:298-310.)