Abstract 12871: Left Atrial Appendage Occlusion in Patients With Atrial Fibrillation and Hypertrophic Cardiomyopathy

Introduction: Patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF) are at increased stroke risk in comparison to those without HCM. The role of left atrial appendage occlusion (LAAO) in these patients is unclear. Methods: In this retrospective cohort study, we identified patients with HCM and AF using the National Readmission Dataset from 2016-19. Patients were stratified based on LAAO status. The primary efficacy outcome was a composite of any stroke (ischemic and hemorrhagic), TIA, and all-cause mortality. The primary safety outcome was a composite of major bleeding and pericardial complications. Individual components of the primary outcomes were secondary outcomes. Patients were matched using inverse probability of treatment weighting. Cox-proportional hazard regression was applied to calculate hazard ratio (HR) with 95% confidence interval (CI) on matched cohorts. Results: We identified 71,980 patients with HCM and AF. Of these, 1,351 (1.9%) patients underwent LAAO. Those who underwent LAAO were significantly younger than those who did not (67.5±10.1 years vs. 70.0±13.1 years, p<0.001) and were more likely to be male (54.6% vs. 45.4%). LAAO was associated with a lower risk of the primary efficacy outcome (2.5% vs. 5.4%, HR: 0.38; 95% CI: 0.17-0.88; p=0.024) and the primary safety outcome (2.9% vs. 6.8%, HR: 0.39; 95% CI: 0.23-0.66, p=0.001). LAAO associated with reduced major bleeding (1.6% vs. 6.0%, HR 0.34, 95% CI 0.18-0.64, p=0.001), GI bleeding (0.2% vs. 1.3%, HR 0.22; 95% CI: 0.06-0.79, p=0.02), blood transfusions requiring admission (2.10% vs. 4.90%, HR 0.37, 95% CI 0.19-0.73, p=0.004), and admissions for bleeding (0.50% vs. 2.30%, HR 0.20, 95% CI 0.07-0.58, p=0.003). Pericardial complications were similar in both groups. Conclusion: LAAO was associated with a lower risk of stroke and major bleeding in patients with HCM and AF. Future prospective studies on the safety and efficacy of LAAO in concurrent AF and HCM are needed.