Mechanical mitral valve prosthesis: Should the INR be above 2 when aspirin is added to the oral anticoagulant?

Background Our aim is to avoid thrombo-embolic and bleeding events in mechanical mitral valve prostheses and find a solution for the difficult adjustment of the INR with the given Vitamin K Antagonists/Oral anticoagulants (VKA) by adding small dose of Aspirin (75 or 81 mg/day)to the oral anticoagulants. Methods We revised the data of 183 patients who had been submitted for mechanical mitral valve replacement between January 2007 and January 2011 and followed for 2–3 years post operative. All of them had been replaced with St.Jude prostheses. 104 of them received Aspirin with the VKA, referred to as group A; group B patients (79 patients) received only VKA. We followed both groups clinically, by coagulation profile and by echocardiography for 2–3 years to assess the INR and the state of the valve in response to the added Aspirin to the VKA. Results In the cases receiving Aspirin added to the oral anticoagulants we found less incidence of malfunctioning valves, less thrombo-embolism and less bleeding events. There were lower doses of oral anticoagulants taken, lower figures of INR in group A than in group B. Conclusions Aspirin added to oral anticoagulants post MVR had the advantages of being safe, convenient and reliable with no need to frequently adjust the oral anticoagulants doses or fear of thrombo-embolic events.