Abstract DP135: Stroke After Left Atrial Appendage Occlusion: Comparative Outcomes of Amulet and Watchman Devices

Background: A Left atrial appendage occlusion (LAAO) or closure device is used in patients with atrial fibrillation who are poor candidates for anticoagulation and require cardioembolic stroke prophylaxis. Despite the widespread appeal, ischemic stroke may still occur, either due to a device-related thrombus (DRT) or a Peri-device leak (PDL). Hence, our study aims to examine clinical challenges when stroke occurs after LAAO and compare the outcomes between the Amulet and Watchman devices. Methods: We reviewed the Amulet Investigational Device Exempt (IDE) trial, along with seven meta-analyses and 12 multicenter registries (totalling 20 peer-reviewed articles) that reported stroke, PDL, DRT, and long-term anticoagulation after LAAO placement. We also used AI for assistance in helping us frame our thoughts more coherently. Results: In the Amulet IDE trial, for stroke and systemic embolization within 18 months, we found that the Amulet device (2.8%) was comparable to the Watchman device (2.8%) (HR 1.00, 95% CI {0.60–1.68}, p=0.99). Complete closure at the 45-day mark was higher with the Amulet device (98.9%) compared to the Watchman device (96.8%), with p=0.02. However, procedure-related complications, namely pericardial effusion, were higher with the Amulet device (4.5% vs 2.5%, p=0.04). DRT occurred in 3.4% of Amulet and 4.8% of Watchman patients; interestingly, however, it appeared earlier in the Amulet group and later in the Watchman cohort (p=0.03). In various meta-analyses, PDL occurred in approximately 26% of patients (about 1 in 4) when examined with transesophageal echocardiography. Additionally, these patients had twice the risk of suffering a thromboembolic event (RR 2.1, 95% CI {1.6–2.8}, p<0.001). Even small peri-device leaks (0–5 mm) carried a significant risk of thromboembolic events (HR 1.8, 95% CI {1.3–2.5}). At 5 years, patients who received the Amulet device had higher rates of anticoagulation discontinuation (94%) compared to those who received the Watchman device (90.9%), with OR 1.45 (95% CI {1.10–1.91}, p=0.01). Conclusion: Patients receiving the Amulet device had several benefits, including lower rates of DRT and higher rates of discontinuation of long-term anticoagulation therapy. Despite increased procedural complications, the preferred device in patients with a high risk of recurrent cerebrovascular events was the Amulet.