Direct Versus Indirect Bypass in Early-Stage Moyamoya (Suzuki I-III): A Propensity Score-Weighted Study

Area of Science:

• Neurosurgery
• Vascular Neurology
• Medical Imaging

Background:

• Moyamoya angiopathy (MMA) treatment lacks stage-specific surgical strategy evidence.
• Existing studies often combine different Suzuki grades, obscuring technique-specific outcomes.

Purpose of the Study:

• To compare direct revascularization (DR) versus indirect revascularization (IR) in adults with stage-restricted MMA (Suzuki grades I-III).
• To evaluate the impact of surgical strategy on perioperative and follow-up stroke rates and functional outcomes.

Main Methods:

• Retrospective multicenter cohort study of 208 hemispheres (104 DR, 104 IR) in adults with MMA (Suzuki I-III).
• Propensity score weighting (PSW) using Covariate Balancing Propensity Scores (CBPS) to adjust for baseline differences.
• Outcomes analyzed included symptomatic stroke, perioperative stroke, complications, discharge scores (NIHSS/mRS), length of stay, and follow-up stroke. Stroke-free survival was compared using Kaplan-Meier analysis.

Main Results:

• Unadjusted analyses revealed no significant differences between DR and IR in perioperative stroke (10.5% vs. 8.6%), symptomatic perioperative stroke, complications, discharge scores, or length of stay.
• Follow-up stroke rates (8.6% vs. 5.8%) and stroke-free survival (log-rank p=.40) did not differ significantly between the groups.
• PSW analysis confirmed no significant differences in clinical outcomes between DR and IR for stage-restricted MMA.

Conclusions:

• In adults with early-stage Moyamoya angiopathy (Suzuki I-III), direct revascularization and indirect revascularization demonstrate comparable clinical outcomes.
• Surgical technique selection for MMA should be individualized, considering patient anatomy, hemodynamics, and institutional expertise.
• Further prospective, stage-stratified studies are needed to standardize endpoints and confirm these findings.