Aspirin After Oral Anticoagulants for Prevention of Recurrence in Patients with Unprovoked Venous Thromboembolism. the Warfasa STUDY

Abstract Abstract 543 Background A recurrence occurs in 15–20% of patients with unprovoked venous thromboembolism (VTE) in the two years after the withdrawal of oral anticoagulant treatment. Extending anticoagulant treatment is effective but associated with increased bleeding risk. We assessed the efficacy and safety of aspirin for the prevention of VTE recurrence after a conventional course of oral anticoagulation. Methods Warfasa was an investigator-initiated double-blind randomized placebo-controlled event-driven study. Patients with a first-ever unprovoked VTE who had completed 6–12 months of oral anticoagulant treatment were randomized to receive aspirin, 100 mg daily, or placebo for a…