WARFASA Trial Summary
The WARFASA trial was a multicenter, double-blinded, randomized, placebo-controlled trial to assess whether aspirin could reduce the recurrence of venous thromboembolism (VTE) in patients who already had an unprovoked VTE and had taken an oral anticoagulant (OAC) for 6-18 months.
Of 403 patients who had unprovoked VTE and underwent 6-18 months of OAC, 205 patients were randomized to take 100 mg of daily Aspirin and 197 patients were randomized to a placebo.
At the 2-year follow-up, the recurrence risk of VTE was significantly decreased in the aspirin group vs. the placebo group (6.6% vs. 11.2%; p = 0.02). There was no significant difference in bleeding (1.9% vs. 2%; p=0.97) nor deaths (3% vs. 2.5%; p=0.95) between the two groups.
Following 6-18 months of OAC after unprovoked VTE, aspirin reduced reoccurrence of VTE after cessation of anticoagulant treatment but did not cause any significant difference in major bleeding risk nor death rate.
The main finding of the WARFASA trial: aspirin reduces VTE reoccurrence after cessation of OAC.