Amulet or Watchman Device for Percutaneous Left Atrial Appendage Closure: Primary Results of the SWISS-APERO Randomized Clinical Trial

Abstract

Background: No study has so far compared Amulet with the new Watchman FLX in terms of residual left atrial appendage (LAA) patency or clinical outcomes in patients undergoing percutaneous LAA closure (LAAC). Methods: In the investigator-initiated SWISS APERO trial, patients undergoing LAAC were randomized (1:1) open-label to receive Amulet or Watchman 2.5 or FLX (Watchman) across 8 European centres. The primary endpoint was the composite of justified crossover to a non-randomized device during LAAC procedure or residual LAA patency detected by cardiac computed tomography angiography (CCTA) at 45 days. The secondary endpoints included procedural complications, device related thrombus (DRT), peridevice leak (PDL) at transesophageal echocardiography (TEE) and clinical outcomes at 45 days. Results: Between June 2018, and May 2021, 221 patients were randomly assigned to Amulet (111 [50.2%]) or Watchman (110 [49.8%]), of whom 25 (22.7%) patients included before October 2019 received Watchman 2.5, and 85 (77.3%) patients received Watchman FLX. The primary endpoint was assessable in 205 (92.8%) patients and occurred in 71 (67.6%) Amulet and 70 (70.0%) Watchman patients respectively (risk ratio [RR] 0.97 [95% CI 0.80- 1.16]; P=0.713). A single justified cross-over occurred in an Amulet patient who fulfilled LAA patency criteria at 45-day CCTA. Major procedure related complications occurred more frequently in the Amulet group (9.0% vs. 2.7%; P=0.047), owing to more frequent bleeding (7.2% vs.1.8%). At 45 days, the PDL rate at TEE was higher with Watchman than Amulet (27.5% vs. 13.7%, p=0.020), albeit none was major (i.e. > 5 mm), whereas DRT was detected in 1 (0.9%) patient with Amulet and 3 (3.0%) patients with Watchman at CCTA and in 2 (2.1%) and 5 (5.5%) patients at TEE, respectively. Clinical outcomes at 45 days did not differ between the groups. Conclusions: Amulet was not associated with lower rate of the composite of crossover or residual LAA patency compared with Watchman at 45-day CCTA. Amulet, was however associated with lower PDL rates at TEE, higher procedural complications and similar clinical outcomes at 45 days compared with Watchman. The clinical relevance of CCTA-detected LAA patency requires further investigation. Clinical Trial Registration: URL https://clinicaltrials.gov Unique Identifier NCT03399851

A newly designed disk-lobe occluder with isogenous barbs for left atrial appendage closure: Initial multicenter experience

“…In the Amulet IDE trial, the rate of major procedurerelated complications with the Amulet device was nearly twice higher than that with the Watchman 2.5 device (4.5% vs. 2.5%) (15). In the SWISS-APERO trial, the incidence of major procedure related complications in the Amulet group was higher than that in the Watchman 2.5/Watchman FLX (9.0% vs. 2.7%) (16). Thus, the LAAC procedure with dual-seal device seems less safe than that with singleseal device.…”

“…Clinically relevant PEF is one of the most severe complications after LAAC. The rate of clinically relevant PEF of LAAC in the perioperative period with ACP and Amulet was 3.5-3.8%, 2.7-4.0%, respectively (5,(14)(15)(16)19). In the multicenter experience with ACP, the incidence of clinically relevant PEF was relatively low (1.4%), yet two patients died of PEF (20).…”

Periprocedural Pericardial Effusion Complicating Transcatheter Left Atrial Appendage Occlusion: A Report From the NCDR LAAO Registry

“…Large postmarket registries will be essential to confirm the apparently reduced rate of in-hospital PE observed in a recent study with that device. 6 Further studies are also required to determine whether the higher rate of PE with the Amulet device 5,8 persists with increased operator experience and to compare the rates of PE between the Amulet and the current-generation Watchman FLX. Even with improvements in device safety, PE will still occur to some extent with transcatheter LAAO and will remain one of the most important potential complications of the procedure.…”

Amplatzer Amulet™ left atrial appendage occluder: A step‐by‐step guide to device implantation

“…Pericardial effusion rates in the first 30 days post LAAO with Amulet were balanced by lower DRT rates despite a dual antiplatelet therapy (DAPT)‐only postimplant regimen in the majority of subjects. Direct comparisons of Watchman FLX to Amulet as regards complete LAA closure by computed tomography angiography (CTA) versus transesophageal echocardiography (TEE) support a comparable occlusion rate 9,10 …”

“…Direct comparisons of Watchman FLX to Amulet as regards complete LAA closure by computed tomography angiography (CTA) versus transesophageal echocardiography (TEE) support a comparable occlusion rate. 9,10 Achieving a complete seal with Amulet is dependent both on the coaxial deployment of a stable and modestly compressed "lobe" inserted into the LAA neck, followed by placement of the sealing disc with circumferential contact to the left atrial wall ideally from the tip of the left pulmonary vein-LAA (LPV-LAA) ridge to the edge of the mitral valve annulus (see Figure 1). The lobe should be anchored with 2/3 of the lobe height below the axis of the left circumflex coronary artery.…”