One-Year Outcomes After Amulet or Watchman Device for Percutaneous Left Atrial Appendage Closure: A Prespecified Analysis of the SWISS-APERO Randomized Clinical Trial

Abstract

P ercutaneous left atrial appendage (LAA) closure (LAAC) prevents thromboembolisms in patients with atrial fibrillation. However, residual LAA patency after LAAC has been associated with higher thromboembolic risk, especially when detected remotely after the procedure. 1 Residual leaks are typically assessed by transesophageal echocardiography or cardiac computed tomography angiography (CCTA), and the latter imaging modality provides a comprehensive operator-independent assessment and higher sensitivity compared with transesophageal echocardiography. 2 The SWISS-APERO trial (Comparison of Amulet Versus Watchman/FLX Device in Patients Undergoing Left Atrial Appendage Closure; URL: https://clinicaltrials.gov; Unique identifier: NCT03399851) is the first random-ized comparison between Watchman FLX (Boston Scientific) and Amplatzer Amulet (Abbott), which are the 2 most frequently used devices for LAAC worldwide. 3,4 Patients with nonvalvular atrial fibrillation and clinically indicated LAAC were eligible if they provided written informed consent and had a CHA 2 DS 2-VASc score of ≥2 and either HAS-BLED score of ≥3 or presence of high-bleeding-risk features. 3 The key exclusion criteria included the presence of LAA thrombus or LAA morphology not suitable for both study devices at trans-esophageal echocardiography. All patients randomized to Watchman before October 2019 received Watchman 2.5; Watchman FLX was used exclusively thereafter. Postimplantation treatment was left to discretion of the treating physician. At 13 months (395±30 days), patients underwent an onsite clinical visit and CCTA. The CCTA images and clinical events were centrally and blindly assessed. LAA was defined as patent appendage (PA) if LAA density was ≥100 Hounsfield unit or ≥25% of that of the left atrium. 3,4 In patients with PA, the presence of visible leaks was adjudicated as intradevice leak, peridevice leak, or mixed leak if contrast medium was visible along the entire length or part of the length of the device or as PAs with no visible leak if none of the above was detected. Device-related thrombus was defined as homogeneous hypoattenu-ated thickening on the atrial surface of the device and centrally adjudicated as definitive or possible device-related thrombus. 3 The trial was an investigator-initiated trial, partially supported by a research grant from Abbott (St. Jude Medical/Abbott, North Plymouth, MN). The trial protocol was approved by the institutional review boards, and all patients provided informed consent before enrollment. The imaging end points were analyzed with the χ 2 test, and risk ratios (RRs) with 95% CIs are reported. The clinical end points were analyzed with Cox proportional hazards model, and hazard ratios with 95% CIs are reported. Data were analyzed according to the intention-to-treat