Artivion, Inc. (NYSE: AORT), a US-based cardiac and vascular surgery company focused on aortic disease, announced on Friday that it has halted the PROACT Xa clinical trial, a prospective, randomised, trial, aimed at determining if patients with an On-X mechanical aortic valve can be maintained safely and effectively on apixaban rather than on warfarin.

The company has taken this decision based on the recommendation of the trial's independent Data and Safety Monitoring Board (DSMB) because of the lack of evidence supporting non-inferiority of apixaban to warfarin for valve thrombosis and thromboembolism.

The study began enrolling subjects in April 2020. The DSMB has revealed that blood clots, resulting in stroke, occurred more frequently in patients receiving apixaban and that continuing the trial was unlikely to achieve the primary endpoint while possibly exposing patients to increased risk.