PROACT Xa - A Trial to Determine if Participants With an On-X Aortic Valve Can be Maintained Safely on Apixaban

  • End date
    Jul 8, 2024
  • participants needed
  • sponsor
    Artivion Inc.
Updated on 8 August 2022
apixaban 5 mg


Currently, warfarin is the only approved anticoagulation for patients with mechanical valves. The purpose of this study is to determine if participants with an On-X Prosthetic Heart Valve / On-X aortic valve can be maintained safely and effectively on apixaban. Both the On-X aortic valve and apixaban have been approved for use by the US Food and Drug Administration (FDA) but they have not been approved to be used together.


There is an unmet clinical need for an alternative to warfarin, such as a direct oral anticoagulant (DOAC), as anticoagulation in participants with an aortic mechanical prosthetic valve. Some participants may be genetically hyper- or hypo-responsive to warfarin, which makes management difficult. Another small group of participants is allergic to warfarin. A much larger group of participants has difficulty maintaining warfarin control due to dietary and drug interactions. Finally, the requirement for routine blood testing makes people reluctant to take warfarin. All of these factors drive younger participants in need of aortic valve replacement (AVR) toward selection of a tissue valve instead of a mechanical valve. Despite multiple studies (randomized, matched and risk adjusted) that show that tissue valves are associated with worse outcomes, younger participants choose this type of valve to avoid warfarin. In addition, multiple clinical studies have shown valve reoperation rates are higher for tissue valves used in these younger participants. Providing an alternative to warfarin anticoagulation may lead younger participants to choose a mechanical valve with greater durability and better clinical outcomes.

Condition Aortic Valve Disease, Aortic Valve Stenosis, Aortic Valve Failure
Treatment Warfarin, Apixaban 2.5 mg, Apixaban 5 mg, On-X Aortic Mechanical Valve
Clinical Study IdentifierNCT04142658
SponsorArtivion Inc.
Last Modified on8 August 2022


Yes No Not Sure

Inclusion Criteria

Male or female at least 18 years of age at the time of giving informed consent
Participants currently receiving warfarin anticoagulation and who are able to receive warfarin with a target INR 2.0 to 3.0
Participants are able to take low-dose aspirin at a dose of 75 -100 mg daily or have a documented contraindication to aspirin use
Implantation of an On-X mechanical valve in the aortic position at least 3 months (90 days) ago
Female participants of childbearing potential, including those who are less than 2 years post-menopausal, must agree to, and comply with using a highly effective method of birth control (eg, barrier contraceptives [condom or diaphragm with a spermicidal gel], hormonal contraceptives [implants, injectables, combination oral contraceptives, transdermal patches, or contraceptive rings], intrauterine devices or sexual abstinence) while partaking in this study. In addition, all women of childbearing potential must agree to continue to use birth control throughout the study until last study visit
Informed of the full nature and purpose of the study, including possible risks and side effects, given ample time and opportunity to read and understand this information, and sign and date the written informed consent before inclusion in the study

Exclusion Criteria

Mechanical valve in any position other than aortic valve
Any cardiac surgery in the three months (90 days) prior to enrollment
Need to be on aspirin >100 mg daily or a P2Y12 inhibitor (clopidogrel, ticagrelor, prasugrel, or ticlopidine)
Known hypersensitivity or other contraindication to apixaban
On dialysis or a creatinine clearance < 25 mL/min
Ischemic stroke or intracranial hemorrhage within 3 months
Active pathological bleeding at the time of screening for enrollment
Active endocarditis at the time of screening for enrollment
Pregnant, plan to become pregnant, or are breast feeding
On concomitant combined strong P-gp and CYP3A4 inducers or inhibitors
History of non-compliance with recommended monthly INR testing
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