Outcomes of the roll-in cohort of the Amulet IDE trial of left atrial appendage occlusion

BACKGROUND Left atrial appendage (LAA) occlusion is an alternative therapy to oral anticoagulants to reduce stroke risk in patients with nonvalvular atrial fibrillation (NVAF). The Amulet IDE trial compared the Amplatzer(TM) Amulet(TM) occluder (Abbott) with the Watchman(TM) 2.5 device (Boston Scientific) for LAA occlusion in patients with NVAF. OBJECTIVE The purpose of this study was to describe outcomes of the Amulet IDE trial roll-in cohort. METHODS At US sites up to 3 patients per implanter could be implanted with the Amulet occluder in the roll-in phase. The primary Endpoints in the Amulet IDE trial included safety (composite of procedure-related complications, all-cause death, or major bleeding at 12 months), effectiveness (composite of ischemic stroke or systemic embolism at 18 months), and rate of LAA occlusion at 45 days. RESULTS A total of 201 roll-in patients were enrolled. Device success occurred in 99% of patients, and device closure (residual jet <= 5 mm) was observed in 98.9% of patients at 45 days. The safety endpoint rate was numerically higher (worse) in the roll-in cohort compared to the randomized Amulet occluder cohort (18.4% vs 14.5%). Six patients (3.1%) experienced an ischemic stroke and 0 patients with a systemic embolism within 18 months, which was similar to the primary effectiveness endpoint rate in the randomized Amulet occluder cohort (2.8%). CONCLUSIONS Despite lack of experience of the operators with the Amulet occluder in the roll-in phase, device implant success was high, a high rate of device closure was achieved, and low stroke rates were observed in patients with NVAF.