Presence of Collaterals from the Contralateral Hemisphere on Preoperative Angiogram Predicts Failure of Encephalo-Duro-Arterio-Synangiosis (EDAS) in Adult Patients with Moyamoya Disease

BACKGROUND AND PURPOSE: Moyamoya disease (MMD) is characterized by chronic progressive stenosis of intracranial vessels and subsequent formation of abnormal collateral vessel networks. Indirect revascularization techniques, such as encephalo-duro-arterio-synangiosis (EDAS), promote angiogenesis to restore perfusion but have variable success rates. This study aimed to identify clinical and radiographic predictors of successful collateral vessel in-growth after EDAS, emphasizing the role of contralateral interhemispheric collaterals. MATERIALS AND METHODS: We conducted a single-center retrospective analysis of cerebral hemispheres from adult patients with MMD who underwent EDAS. We assessed demographic characteristics, clinical presentation, procedural details, and clinical and radiographic outcomes. Angiographic outcomes were assessed using the Orbital Grading system. Univariate analysis was performed to identify factors associated with favorable postoperative collateral development. Consequently, preoperative contralateral interhemispheric collateralization was quantitatively evaluated through pixel density analysis on digital subtraction angiography, comparing the Moyamoya-affected hemisphere with the contralateral hemisphere. RESULTS: Sixty-one MMD hemispheres of 43 adult patients were included in the study. Median times to last clinical and angiographic follow-up were 29.9 months and 13.6 months, respectively. Higher Suzuki stages (V and VI; P =