Clinical features, treatment and long-term outcomes of hemorrhagic moyamoya disease in children: an extensive follow-up study

BACKGROUND: Paediatric hemorrhagic moyamoya disease (hMMD) is rare, with unclear clinical features and long-term outcomes owing to limited data. We comprehensively evaluated the clinical characteristics, prognosis and optimal treatment strategies for pediatric hMMD. METHODS: We screened paediatric patients with hMMD hospitalised between November 2003 and December 2024. Clinical features, treatments and long-term outcomes were retrospectively analysed. Multivariate logistic regression was used to evaluate risk factors for rebleeding and poor prognosis. RESULTS: During the first decade, hemorrhagic events were rare. However, in the second decade, females experienced hemorrhage at age 13-15 years and males at 10-12 years. Over 1103 patient-years, 96 hemorrhagic events occurred. Before encephaloduroarteriosynangiosis (EDAS), seven rehemorrhage instances occurred among 94 patients over 93.2 patient-years of observation. A modified Rankin Scale score ≥3 on admission independently predicted rehemorrhage (p=0.040; OR 5.280; 95% CI 1.083 to 25.739), while early EDAS (within 3 months of the first hemorrhage) significantly reduced this risk (p=0.043; OR 0.107; 95% CI 0.012 to 0.933). EDAS patients had lower rehemorrhage rates compared with their natural history. Anterior choroidal artery dilation and early-onset and delayed-onset posterior cerebral artery involvement increased postoperative complication risk. Early EDAS reduced postoperative complications (p=0.028; OR 0.219; 95% CI 0.057 to 0.845). CONCLUSION: Although rare, paediatric hMMD carries a high rebleeding rate. The second decade of life may represent the peak period for bleeding in paediatric patients with MMD, necessitating close monitoring. Early EDAS reduces rebleeding and postoperative complications in hMMD. Compared with the natural course, EDAS safely reduces paediatric rehemorrhage.