Outcomes of Bypass Surgery in Adult Moyamoya Disease by Onset Type

Abstract

Importance: Moyamoya disease (MMD) is a rare chronic cerebrovascular disease, and the outcomes of bypass management in adult patients remain controversial. Objective: To categorize adult MMD based on asymptomatic, ischemic, and hemorrhagic onset and compare the outcomes (death, hemorrhagic stroke [HS], and ischemic stroke [IS]) of bypass surgery (direct or indirect) with those of conservative management. Design, Setting, and Participants: This retrospective, nationwide, population-based longitudinal cohort study used Korean National Health Insurance Research data to identify adults (aged ≥15 years) with MMD who were diagnosed between January 1, 2008, and December 31, 2020, and followed up until December 31, 2021 (median follow-up, 5.74 [IQR, 2.95-9.42] years). A total of 19700 participants (3194 with hemorrhagic, 517 with ischemic, and 15989 with asymptomatic MMD) were included. Data were analyzed from January 2 to April 1, 2023. Exposures: Bypass surgery and conservative management. Main Outcomes and Measures: Death constituted the primary outcome; secondary outcomes consisted of HS or IS. Kaplan-Meier survival curve and Cox proportional hazards regression analysis were applied. The propensity score-matching and stratified analyses were performed to control covariate effects. Results: A total of 19700 patients (mean [SD] age, 45.43 [14.98] years; 12766 [64.8%] female) were included. Compared with conservative management, bypass was associated with a reduced risk of death (adjusted hazard ratio [AHR], 0.50 [95% CI, 0.41-0.61]; P