Randomized On-X Anticoagulation Trial

Study ID

Cancer Related

Healthy Volunteers

Study Sites

  • Clements University Hospital

Parvin Mohazabnia

Principal Investigator
Michael Wait, M.D.

Official Title

Prospective Randomized On-X Anticoagulation Clinical Trial (PROACT)

Brief Overview

Various patient groups with the On-X Valve can be maintained safely on lower doses of blood
thinner(Coumadin®) or on antiplatelet drugs (aspirin/Plavix®) only rather than the standard
dose of Coumadin and aspirin presently recommended by ACC/AHA or ACCP professional


This is a longitudinal, randomized (randomization to occur at the 3 month follow-up) study
comparing the On-X valve on low dose anticoagulation (test group) to concomitant control
groups of On-X valves receiving standard Coumadin/aspirin therapy, and also to FDA objective
performance criteria (OPC) for heart valve replacement. It is a multicenter study consisting
of 20 centers in the United States enrolling no more than 1200 patients (200 in each of 6
groups). There are three test arms of the study: low risk aortic valve replacement, high
risk aortic valve replacement and mitral valve replacement. Each arm has an equivalent
control. Test therapies are: low risk aortic valve replacement - aspirin/Plavix, high risk
aortic valve replacement - Coumadin at INR of 1.5 to 2.0 plus aspirin, and mitral valve
replacement - Coumadin at an INR of 2.0 to 2.5 plus aspirin. Follow-up will run for 5 years
in each patient.

Participant Eligibility

Inclusion Criteria:

- Patients requiring isolated aortic valve replacement (AVR), or isolated mitral valve
replacement (MVR).

- AVR patients receiving low dose or antiplatelet only anticoagulation will be divided
into groups at low risk and high risk for thromboembolism with all patients being in
the low risk group except for patients with the following conditions which place a
patient in the high risk group:

- Chronic atrial fibrillation

- Left ventricular ejection fraction < 30 %

- Enlarged left atrium >50mm diameter

- Spontaneous echo contrasts in the left atrium

- Vascular pathology

- Neurological events

- Hypercoagulability

- Left or right ventricular aneurysm

- Lack of platelet response to aspirin or clopidogrel

- Women receiving estrogen replacement therapy

- Concomitant cardiac surgery is allowed

- Adult patients

Exclusion Criteria:

- Right side valve replacement

- Double (aortic plus mitral) valve replacement

- Patients with active endocarditis at the time of implant

- Previous confirmed or suspected thromboembolic event or thrombophlebitis

- Other terminal illness

- Patients who are in an emergency state

- Inability to return for required follow-ups

- Patients with an On-X valve implanted within the study and subsequently explanted

- Patients who are known to be pregnant, plan to become pregnant or are lactating

- Patients with acquired immunodeficiency syndrome or know to be HIV positive

- Patients who are prison inmates or known drug or alcohol abusers

- Patients unable to give adequate informed consent.