Clinical Outcomes of Clipping and Coiling in Elderly Patients with Unruptured Cerebral Aneurysms: a National Cohort Study in Korea

Background: We aimed to analyze outcomes of clipping and coiling in treating unruptured intracranial aneurysms (UIAs) in elderly patients and to identify the age at which perioperative risk increases based on national cohort data in South Korea. Methods: The incidence of perioperative intracranial hemorrhage (ICRH), perioperative cerebral infarction (CI), mortality, and moderate to severe disability data of the patients who underwent coiling or clipping for UIAs were retrieved. Estimated breakpoint (EBP) was calculated to identify the age at which the risk of treatment increases. Results: A total of 38,207 patients were treated for UIAs. Among these, 22,093 (57.8%) patients underwent coiling and 16,114 (42.2%) patients underwent clipping. The incidence of ICRH, requiring a secondary operation, within 3 months in patients >= 65 years that underwent coiling and clipping was 1.13% and 4.81%, respectively, and that of both groups assessed were significantly higher in patients >= 75 years (coiling, P = 0.013, relative risk (RR) 1.81; clipping, P = 0.015) than younger patients. The incidence of CI within 3 months in patients aged >= 65 was 13.90% and 9.19% in the coiling and clipping groups, respectively. The incidence of CI after coiling in patients aged >= 75 years (P < 0.001, RR 1.96) and after clipping in patients aged >= 70 years (P < 0.001, RR 1.76) was significantly higher than that in younger patients. The mortality rates within 1 year in patients with perioperative ICRH or CI were 2.41% and 3.39% for coiling and clipping groups, respectively, in patients >= 65. These rates increased significantly at age 70 in the coiling group and at age 75 for the clipping group (P = 0.012 and P < 0.001, respectively). Conclusion: The risk of treatment increases with age, and this risk increases dramatically in patients aged >= 70 years. Therefore, the treatment decisions in patients aged >= 70 years should be made with utmost care.