Impact of RNF213 founder polymorphism (p.R4810K) on the postoperative development of indirect pial synangiosis after direct/indirect combined revascularization surgery for adult Moyamoya disease.

Direct superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis combined with indirect pial synangiosis provides favorable surgical collaterals for Moyamoya disease (MMD), especially in adults; however, factors leading to the development of each direct and indirect collateral are not well documented.We aimed to investigate the association between RNF213 founder polymorphism (p.R4810K) and each direct and indirect collateral development. By qualitative and quantitative evaluations of direct and indirect surgical collaterals using time-of-flight MR angiography, postoperative development of each type of bypass was evaluated independently into two categories. Multivariate logistic regression analysis was performed to study the contributing factors for the development of each surgical collateral. Excellent development of postoperative direct and indirect bypass was observed in 65 hemispheres (70%) by qualitative evaluation, which was confirmed by quantitative evaluation. Multivariate logistic regression analysis of excellent indirect bypass development revealed a significant positive correlation with the p.R4810K (odds ratio, OR4.0; 95%-confidence interval, CI 1.2-16), advanced MR angiographic stage (OR9.5; 95%CI 1.7-73), and preoperative middle meningeal artery caliber (OR6.8; 95%CI 1.8-35), but a significant negative correlation was found with the excellent direct bypass development (OR0.17; 95%CI 0.03-0.75). No significant correlation was observed between excellent direct bypass development and the p.R4810K (OR0.95; 95%CI 0.37-2.4).In conclusion, excellent development of indirect collaterals after STA-MCA anastomosis combined with indirect pial synangiosis occurs more frequently in adult MMD with the RNF213 founder polymorphism, suggesting a role of the p.R4810K variant for marked in-growth of indirect collaterals and the utility of preoperative genetic analysis.