Abstract WMP43: Long-term Mortality in Moyamoya Patients According to Presentation Type and Bypass Surgery in South Korea

Abstract

Background: Survival outcomes in moyamoya patients according to initial presentation type and bypass surgery have not been clearly revealed. Methods: We investigated mortality in moyamoya disease (MMD) patients using Korean National Health Insurance database from 2006 to 2015 allowing wash-out period of previous 4 years. MMD type was classified into ischemic, hemorrhagic, and asymptomatic MMD. Bypass surgery group included the patients who underwent bypass surgery within 1 year after MMD diagnosis. Survival analysis was performed according to initial presentation type and bypass surgery using Kaplan-Meier method and Cox proportional hazard model. Results: The total number of patients with newly diagnosed MMD was 12146 with a female-to-male ratio of 1.81, of which ischemic type was identified in 3671 (30.2%), hemorrhagic type was in 2449 (20.2%), and asymptomatic type was in 6026 (49.6%) patients, respectively. There were 3942 (32.5%) patients in bypass surgery group and 8204 (67.5%) patients in non-bypass group. The 5- and 10-year survival rates in ischemic, hemorrhagic, and asymptomatic type were 92.5% and 88.9%, 85.3% and 76.3%, and 96.3% and 94.3%, respectively (Log-rank test; P<0.001, P<0.001). After adjusting age, sex, and presentation type, bypass surgery demonstrated HRs of 0.597 (95% CI 0.486-0.733, P<0.001) and 0.595 (95% CI 0.429-0.719, P<0.001) for 5- and 10-year mortality, respectively. Conclusion: This study showed that MMD patients had different survival courses according to initial presentation type. Adult MMD patients with hemorrhagic presentation had the worst survival outcome. Bypass surgery group survived longer than non-bypass group did in MMD patients in real-world setting.