Although the On-X aortic valve and apixaban have been approved for use by the U.S. Food and Drug Administration (FDA), they had not been approved to be used together. Between May 2020 and September 2022, the PROACT Xa randomized, multicenter, open-label trial compared the direct factor Xa inhibitor apixaban (Eliquis) with warfarin in patients with bileaflet carbon aortic valves.
A total of 863 patients from 60 sites who were at least 3 months out from aortic valve replacement (AVR) were randomized 1:1 to receive apixaban 5 mg twice daily or warfarin with a target INR of 2–3. Enrolled patients had a median age of 56 years; 24% were female. Among participants, 46% had AVR in the 12 months prior to randomization, 17% had AVR along with an aortic root graft, and 16% were reoperations on the aortic valve. Most patients (93%) received 81 mg of aspirin daily with the assigned anticoagulant.
The study was discontinued on Sept. 21, 2022, at the recommendation of the PROACT Xa Data and Safety Monitoring Board based on observed higher rate of thromboembolic events (valve thrombosis and thromboembolism) in patients randomized to apixaban than warfarin.
Lars Svensson, MD, of the Cleveland Clinic, will present the results of this study Saturday, May, 6, at the American Association for Thoracic Surgery (AATS) 103rd Annual Meeting in Los Angeles, detailing the events that led to the discontinuation.