In earlier prospective studies conducted in patients with symptomatic DVT, the presence of a residual thrombus was associated with an increased risk of thrombotic recurrencies either in idiopathic or provoked venous thrombosis. Interestingly, recurrent events occurred not only in the previously affected veins but also in other sites, thus suggesting that Residual Vein Thrombosis (RVT) may express a pro-thrombotic status. Based on these findings, the detection of RVT may be, therefore, of help in establishing the duration of anticoagulation.