In patients undergoing transcatheter aortic-valve replacement, defects in high-molecular-weight von Willebrand factor multimers and the closure time with adenosine diphosphate (a measure of hemostasis) were closely correlated with postprocedural aortic regurgitation. Postprocedural aortic regurgitation, usually due to paravalvular leak, occurs in 10 to 20% of patients with aortic stenosis who undergo transcatheter aortic-valve replacement (TAVR). 1 – 3 Patients with aortic regurgitation that is more than mild after TAVR have poorer outcomes than those without aortic regurgitation, including increased rates of rehospitalization, death from cardiac causes, and death from any cause at 1 year. 4 Ideally, aortic regurgitation after TAVR should be detected at the time of the procedure, because correction maneuvers can be undertaken immediately. However, despite the combined use of angiography, echocardiography, and hemodynamic evaluation, it is very difficult to identify and . . .