Abstract Body (Do not enter title and authors here): Introduction
The Amulet IDE trial is a prospective, global, clinical trial with 1:1 randomization comparing the AMPLATZER™ Amulet™ Left Atrial Appendage (LAA) Occluder (Abbott) to the Watchman™ 2.5 LAA device (Boston Scientific) in patients with non-valvular atrial fibrillation. This is the first report of the 5-year results from the trial.

Methods
Patients enrolled were at a high risk of stroke or systemic embolism (SE) defined as CHA₂DS₂-VASc score of ≥3. Clinical follow-up occurred at discharge, 45 days, 3, 6, 9, 12, and 18 months and annually through 5 years. An independent echocardiographic core laboratory was used to analyze cardiac images and adverse events were adjudicated by an independent clinical events committee.

Results
A total of 1,878 patients at 108 sites were randomized and 1,833 underwent an implant attempt (n=917 Amulet occluder and n=916 Watchman device) which were used in this analysis (Figure 1). The final 5-year follow-up visit rate was over 80% in both device groups (89.2%; N=595 in Amulet occluder and 83.3%; N=545 in Watchman device). Baseline characteristics were well-matched between the two device groups (75.1 years, 40.0% female, CHA₂DS₂-VASc: 4.6 and HAS-BLED: 3.3). At 5 years, 94.0% of patients were free of OAC in Amulet occluder patients compared to 90.9% in Watchman device patients (p=0.009). Five-year clinical outcomes were similar between the Amulet and Watchman device including the composite of ischemic stroke or SE (7.4% vs. 7.1%; p=0.851), composite of stroke, SE, or cardiovascular (CV) death (20.3% vs. 20.7%; p=0.666), major bleeding (20.1% vs. 20.0%; p=0.882), CV death (14.3% vs. 15.4%; p=0.429), and all-cause death (28.7% vs. 31.1%; p=0.217). Annualized ischemic stroke rates at 5 years were low and similar for Amulet (1.6%/year) and Watchman (1.6%/year) devices resulting in a 78% and 79% reduction in the risk of stroke based on the CHA₂DS₂-VASc scores. Strokes in patients with the Amulet occluder tended to be less severe (n=38 non-disabling, n=11 disabling, n=11 fatal, n=12 unknown) than strokes in patients with the Watchman device (n=19 non-disabling, n=22 disabling, n=17 fatal, n=10 unknown).

Conclusions
The 5-year outcomes from the largest randomized LAAO clinical trial demonstrated the long-term safety and effectiveness of the Amulet occluder and Watchman device. The dual-seal Amulet occluder reduces atrial fibrillation-related thromboembolic events while eliminating the need for long-term OAC.