Current guidelines have no recommendations on the utilization of novel oral anticoagulants, such as dabigatran, for the prevention of thromboembolic events in patients with mechanical heart valves. However, recent studies on the use of dabigatran in patients with atrial fibrillation and animal studies have suggested a new potential role for dabigatran in patients with mechanical heart valves. The study by Eikelboom et al. investigates this important clinical question in a prospective, randomized controlled Phase II clinical trial. The authors randomly assigned 252 patients from 39 centers in ten countries to receive dabigatran or warfarin in a 2:1 ratio. The objective of the study was to validate a dosing regimen for use of dabigatran in patients with mechanical heart valves. The trial was prematurely terminated after a recommendation by the data and safety monitoring board. The composite of stroke, systemic embolism, myocardial infarction and death was 8% in the dabigatran group and 2% in the warfarin group (hazard ratio: 3.37; 95% CI: 0.76–14.95; p = 0.11). There were significantly higher bleeding rates of any type in the dabigatran group (27%) compared with the warfarin group (12%; hazard ratio: 2.45; 95% CI: 1.23–4.86; p = 0.01). These results demonstrated a higher risk and no additional benefits in using dabigatran compared with warfarin in patients with mechanical heart valves.