Enrolment completed for low-risk aortic and mitral patients in prosthetic heart valve study


On-X Life Technologies has announced that enrolment for the low-risk aortic valve and mitral valve patient groups has been completed for its Prospective randomised On-X valve anticoagulation trial, which was initiated with US FDA approval in 2006 and is being conducted at 36 centres throughout the USA and Canada. 

The purpose of the low-risk patient group of the PROACT trial is to determine if qualified recipients of the On-X aortic heart valve can be safely maintained with aspirin and clopidogrel (Plavix). The announcement was made at the American Association for Thoracic Surgery (AATS) annual meeting (2–3 May, New York, USA).

The low-risk patient group of the PROACT trial is comprised of patients requiring aortic valve replacement who meet the low-risk criteria established by the study’s protocol, which was reviewed and approved by the FDA under Investigational Device Exemption (IDE) rules. According to a company press release, this is the only FDA-approved study using aspirin and clopidogrel as the anticoagulant for aortic valve patients receiving a mechanical valve. The mitral valve patient group follows patients taking reduced warfarin.

“The completion of enrolment for the low-risk aspirin and clopidogrel patient group is a very positive sign,” said John Ely, rxecutive vice president of Regulatory Affairs and Quality Assurance for On-X Life Technologies and the primary coordinator of the PROACT trial. “It will allow us to more accurately project event rates and follow-up needs as we progress toward the study’s completion. When the longer-term follow-up data are collected, analysed and reviewed, we will be able to determine whether selected recipients of the On-X valve in the aortic position can be safely managed without warfarin anticoagulation. If that is the case, it will be an important breakthrough for prosthetic valve recipients.”

The press release reported that the On-X valve is the result of a breakthrough in medical grade carbon technology—On-X pure pyrolytic carbon. In addition to providing a more thromboresistant surface, the comparatively high strength of pure On-X carbon enabled On-X LTI to make significant valve design changes that resulted in a prosthesis that acts more like a natural valve in its treatment of blood. It is documented that the On-X valve does not produce the turbulence and blood damage commonly produced by other mechanical heart valve prostheses and therefore significantly reduces the potential for life-threatening blood clots.

Until the completion and analysis of study data, On-X Life Technologies continues to recommend standard anticoagulation therapy as presently prescribed by various professional societies for the On-X valve.