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.