VALVULAR HEART DISEASE: Edited by Thierry MesanaReduced anticoagulation is safe in high-risk patients with the On-X mechanical aortic valveYanagawa, Bobbya; Levitsky, Sidneyb; Puskas, John D.a On Behalf of the PROACT InvestigatorsAuthor Information aDepartment of Cardiothoracic Surgery, Icahn School of Medicine at Mount Sinai Hospital, New York bDivision of Cardiac Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA *See supplementary digital content 1 for list of PROACT investigators, http://links.lww.com/HCO/A24. Correspondence to John D. Puskas, MD, MSc, FACS, FACC, Chair of Cardiothoracic Surgery at Mount Sinai Beth Israel, Director of Surgical Coronary Revascularization, and Department of Cardiothoracic Surgery, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Tel: +1 212 420 5601; fax: +1 212 420 4222; e-mail: [email protected] Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (www.co-cardiology.com). Current Opinion in Cardiology: March 2015 - Volume 30 - Issue 2 - p 140-145 doi: 10.1097/HCO.0000000000000149 Buy SDC Metrics Abstract Purpose of review The goal of anticoagulation in patients with mechanical aortic valve replacement (AVR) is to maintain an optimal international normalized ratio (INR) that minimizes both the risk of bleeding and thromboembolic events. Here, we review the published data on anticoagulation with bileaflet mechanical prostheses, with a focus on the On-X valve (On-X Life Technologies, Austin, TX), which was designed to function with less anticoagulation or, in some cases, antiplatelet therapy only. Recent findings Several long-term follow-up studies with the On-X valve demonstrate low rates of bleeding and thromboembolism with standard and low-dose anticoagulation. The Prospective Randomized On-X Anticoagulation Clinical Trial (PROACT) compared the safety of less aggressive anticoagulation (INR 1.5–2.0) with standard anticoagulation (INR 2.0–3.0) after implantation of On-X aortic prostheses for patients at high risk of thromboembolic events. The updated 5-year data confirm that low-dose warfarin is associated with lower major bleeding (1.6 vs. 3.9%/patient-year; P = 0.007) with no difference in thromboembolic events (0.11 vs. 0.52%/patient-year; P = 0.2). Summary Nonrandomized studies and the PROACT data support the safety and efficacy of maintaining the On-X bileaflet mechanical aortic valve prosthesis at a lower target INR than current guideline recommendations for patients at high risk of thromboembolic events. These results offer the promise of a valve prosthesis with excellent durability combined with reduced anticoagulation-related complications. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.