Comparison of Amplatzer Amulet and Watchman Device in Patients Undergoing Left Atrial Appendage Closure. (SWISS-APERO)

Non-valvular Atrial fibrillation (NVAF) is the most common cardiac arrhythmia and a major cause of morbidity and mortality because of cardioembolic stroke. Oral anticoagulation (OAC) with vitamin K antagonists (VKA) or Non-vitamin K antagonist anticoagulant (NOAC) is the most effective prophylaxis for stroke in NVAF. However (N)OAC therapy is associated with a significant bleeding liability and long-term (N)OAC therapy in patients with NVAF and concomitant high bleeding risk poses safety issues in a sizable and growing population in clinical practice. Thus, a new and emerging therapeutic option in this high-risk patient population is the left atrial appendage closure (LAAC). There are many available systems approved for percutaneous LAAC. One of the most widely used is the Watchman™ system (Boston Scientific), which was tested in the setting of two randomized control trials (RCT), which demonstrated the safety of the procedure and the non-inferiority in terms of stroke reduction compared to OAC. Another device largely used is the Amplatzer Amulet (St. Jude Medical-Abbott). There is no RCT comparing this device with OAC, but many prospective and retrospective studies had shown the same safety profile and the non-inferiority with the OAC. From the very beginning of the LAAC, a crucial assessment is the degree of LAA occlusion granted by the implanted device. Many imaging modalities have been used to assess LAA occlusion, including transesophageal echocardiography (TEE), fluoroscopy or cardiac computed tomography angiography (CCTA). In the setting of available randomized trials, successful closure was defined with the presence of a regurgitant flow ≤ 5 mm assessed with TEE. In the last years several groups assessed the value of CCTA as non-invasive post-procedural surveillance imaging modality after endovascular LAAC to evaluate atrial-side device thrombus, residual leak (and mechanisms thereof), device position, pericardial effusion and most importantly LAA patency. There are currently no randomized controlled trials assessing the degree of LAA occlusion between Amulet and Watchman.