Effects of Very Low Dose Oral Anticoagulation on Thromboembolism and Bleeding Events in Patients With Mechanical Heart Valve Replacement

In mechanical heart valve recipients, self-management of oral anticoagulation can reduce the risk of developing thromboembolic events and improves long-term survival compared with international normalized ratio (INR) control by a general practitioner. Low-dose INR self-management (INR values of 1.8.-2.8 for aortic valve recipients and 2.5 - 3.5 for mitral or double valve recipients) does not increase the risk of thromboembolic events compared to conventional dose INR self-management. Even in patients with a low INR target range, however, the risk of bleeding events is still higher than the risk of thromboembolism. We therefore perform a prospective, randomized trial in 1,800 patients with mechanical heart valve replacement. During the first six postoperative months, low dose INR self-management will be performed by all patients (INR measurement once a week). Thereafter, 600 patients will continue with this treatment regimen, whereas the other 1,200 patients with perform very low dose oral anticoagulation. Out of these 1,200 patients, 600 will perform INR measurement once a week and 600 patients will perform INR measurement twice a week. Patients are followed up for 24 months.