Methods Patients with a first episode of symptomatic unprovoked or provoked proximal Vein Thrombosis (VT) were given Oral Anticoagulant Treatment (OAT) for 3 months. Residual Vein Thrombosis (RVT), ultrasonographically-detected, will be then assessed. Patients without RVT did not continue OAT, whereas those with RVT will be randomized to either stop or continue OAT for 9 more months. Patients were followed-up prospectively focusing on the study outcomes: occurrence of recurrent venous thromboembolism and major bleeding over a period of at least 12 months after OAT discontinuation.