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™ Amulet™ occluder (Abbott) with the Watchman™ 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.