Roost E, Weber A, Alberio L, et al. - A proof-of-principle study was performed to evaluate the anti-Xa inhibitor rivaroxaban as an antithrombotic treatment in patients with recent mechanical aortic valve replacement. In a prospective cohort study, low-risk individuals selected for elective mechanical aortic valve replacement were treated with rivaroxaban 20 mg once daily (OD), started on day 3 postoperatively and given for 6 months. They enrolled ten individuals (median age, 48; range 39 to 60). Six patients indicated aortic valve stenosis, aortic root aneurysm with severe aortic valve regurgitation in 3 patients, and mixed stenosis/regurgitation in 1 patient. They did not observe any thromboembolic or bleeding events and death of any individual. In a pilot study, rivaroxaban 20 mg OD was safe and effective in 10 low-risk individuals with a mechanical aortic heart valve. In individuals with mechanical heart valves, the outcomes warrant larger studies examining the application of anti-Xa inhibitors.