Atrial Appendage Aneurysms: Natural History and Outcomes

Background: Left (LAAA) and right atrial appendage aneurysms (RAAA) are rare entities, and their natural history, management, and long-term outcomes are not well studied. Methods: This retrospective review includes all patients from 2000 to 2021 with atrial appendage aneurysms at our institution identified using an electronic search tool. LAAA and RAAA were confirmed using multimodality imaging and intraoperative findings. Results: We identified 13 (87%) patients with LAAA and 2 (13%) with RAAA. At diagnosis, 11 (73%) were female, mean age was 51.4 ± 18.8 years, and ejection fraction 56.5 ± 13.1%. Three (20%) patients had congenital heart disease including 2 (13%) with atrioventricular septal defects and 1 (7%) with congenitally corrected transposition. LAAA/RAAA was diagnosed due to new-onset atrial fibrillation (AF) in 6 (40%) patients and embolic stroke in 2 (13%). Ten patients had preexisting AF diagnosed 2.9 ± 1.4 years earlier at a mean age of 50.2 ± 15.5 years. Thrombus within the aneurysm was identified in 2 (15%) LAAA patients. All patients were on anticoagulation and follow-up of the cohort from diagnosis was 7.1 ± 6.2 years. Eleven (73%) patients were surgically managed with 7 (64%) lesions excised, 1 (9%) stapled, and 3 (27%) ligated. Postoperative complications occurred in 2 (18%) patients with 1 (7%) developing tricuspid regurgitation and another with pericardial effusion and tamponade. Conclusions: Atrial appendage aneurysm is a rare disease and nearly half of patients present with AF. Surgical treatment with concomitant AF ablation is a reasonable and safe management option.