Low-dose oral anticoagulation in patients with mechanical heart valve prostheses:: final report from the early self-management anticoagulation trial II

Aims In mechanical heart valve recipients, low-dose international normalized ratio (INR) self-management of oral anticoagulants can reduce the risk of developing thrombo-embolic events and improve tong-term survival compared with INR control by a general practitioner. Here, we present data on the safety of low-dose INR self -management. Methods and results In a prospective, randomized multi-centre trial, 1346 patients with a target INR range of 2.5-4.5 and 1327 patients with a target INR range of 1.8-2.8 for aortic valve recipients and an INR range of 2.5-3.5 for mitral or double valve recipients were followed up for 24 months. The incidence of thrombo-embolic events that required hospital admission was 0.37 and 0.19% per patient year in the conventional and low-dose groups, respectively (P=0.79). No thrombo-embolic events occurred in the subgroups of patients with mitral or double valve replacement. The incidence of bleeding events that required hospital admission was 1.52 and 1.42%, respectively (P=0.69). In the majority of patients with bleeding events, INR values were <3.0. Mortality rate did not differ between the study groups. Conclusion Data demonstrate that low-dose INR self-management does not increase the risk of thrombo-embolic events compared with conventional dose INR self -management. Even in patients with low INR target range, the risk of bleeding events is still higher than the risk of thrombo-embolism.