Study design. A1 indicates patients with RVT who continued OAT for 12 months (in total); A2 indicates patients with RVT randomized to stop OAT after 3 months; and B indicates patients without RVT who stopped OAT after 3 months. DVT indicates deep vein thrombosis; RVT, residual vein thrombosis; C-US, compression ultrasonography; and OAT, oral anticoagulant therapy.