Different institutions have different strategies for managing both native and prosthetic aortic valves in recipients of left ventricular assist devices (LVADs). Anticoagulation protocols and pump-flow algorithms remain nonstandardized. We describe our institutional experience with thrombotic complications and our evolving approach to this important clinical problem. We report the cases of 4 HeartMate II LVAD recipients in whom, despite an anticoagulative regimen, thrombus formed on the noncoronary cusp of the aortic valve. The management of the closed aortic valve in LVAD-supported patients remains problematic.