Outcomes for single antiplatelet, dual antiplatelet, or oral anticoagulation after Amulet: Insights from EMERGE LAA post-approval study

Abstract

Background: Outcomes associated with different antithrombotic strategies after Amulet left atrial appendage occlusion (LAAO) are not well described.

Objective: This analysis compared outcomes from patients discharged on dual antiplatelet therapy (DAPT) versus single antiplatelet therapy (SAPT) or oral anticoagulation (OAC) following Amulet implant in the EMERGE LAA post-approval study.

Methods: Patients with a successful Amulet implant and discharged from the hospital between August 14, 2021 and December 15, 2023 and entered into the National Cardiovascular Data Registry (NCDR) LAAO Registry were included. A safety endpoint of all-cause death, stroke, major bleeding, or systemic embolism and effectiveness endpoint of ischemic stroke, systemic embolism, or cardiovascular death were assessed through 6 months as well as major adverse events.

Results: A total of 11,445 patients were included in this analysis with 9355 discharged on DAPT (81.7 %), 606 on SAPT (5.3 %), and 1484 on OAC (13.0 %). Patients in the SAPT group had more comorbid conditions and were at the greatest bleeding risk pre-Amulet implant. At 45-days, clinically relevant closure (≤3 mm peri-device leak) was achieved in >95 % of all patients. At 6 months, the safety endpoint rates were 8.8 %, 7.0 %, and 7.0 % in the DAPT, SAPT, and OAC groups, respectively (p = 0.045) and effectiveness endpoint rates were 2.1 %, 1.6 %, and 1.7 % in the DAPT, SAPT, and OAC groups, respectively (p = 0.511). Despite higher baseline bleeding risk, the SAPT group had numerically lower bleeding rates than the DAPT group through 6 months (DAPT 4.8 % vs. SAPT 3.9 %; HR 1.23 [0.78, 1.95]) with no difference in device-related thrombus rates (DAPT 0.8 % vs. 0.8 % SAPT; HR 0.91 [0.33, 2.50]). However, after adjusting for differences in baseline characteristics, no significant differences (p > 0.05) were noted for any clinical events between the three medication groups at 45 days or 6 months.

Conclusion: In the present cohort of patients treated with Amulet LAAO there were high rates of LAA complete closure, and SAPT emerged as a viable alternative to the current DAPT regimen potentially reducing the risk of bleeding complications in patients at high risk without compromising effectiveness.

Keywords: Amulet; Antithrombotic medication; Atrial fibrillation; LAAO Registry; Left atrial appendage.