The PROTECT AF trial was a randomized controlled trial comparing percutaneous left atrial appendage closure using the WATCHMAN device versus long-term warfarin therapy for stroke prevention in patients with non-valvular atrial fibrillation. The trial found that the device was non-inferior to warfarin for preventing all strokes and deaths, and superior for preventing hemorrhagic strokes. The device was associated with early safety events such as pericardial effusions that decreased over time, and most patients were able to stop warfarin within 45 days of the procedure. The trial demonstrated that the WATCHMAN device offers a safe and effective alternative to long-term warfarin therapy in appropriate patients