Effect of revascularization surgery on cerebral hemodynamics in adult moyamoya disease

Objective: Few studies have reported local hemodynamic changes after revascularization surgery. This study aimed to identify regional hemodynamic changes after combined revascularization surgery for moyamoya disease using single -photon emission computed tomography with N-isopropyl-p-123I-iodoamphetamine. Methods: A total of 46 adults with moyamoya disease who underwent combined revascularization surgery from August 2009 to July 2021 at our facility were enrolled. The combined bypass procedure comprised a single direct bypass to the motor area and encephalo-duro-arterio-myo-synangiosis. The preoperative and postoperative cerebral blood flow (CBF) and cerebral vascular reserve (CVR) in the genu; precentral, central, parietal, angular, temporal, and posterior regions; splenium; hippocampus; and cerebellum were measured. To modify the examination variability, the cerebral -to -cerebellar activity ratio (CCR) was calculated by dividing the counts in the region by those in the cerebellum (CBF-CCR and CVR-CCR). Results: Postoperatively, asymptomatic cerebral infarction occurred in three (6.5%) patients. The CBF-CCR and CVR-CCR improved in the precentral, parietal, and temporal regions and in the overall middle cerebral artery (MCA) territory. Sub -analysis of anterior cerebral artery (ACA) and posterior cerebral artery (PCA) territory hemodynamics revealed that patients with normal preoperative hemodynamics showed no changes in the CBFCCR and CVR-CCR postoperatively, whereas patients with preoperative perfusion impairment exhibited improved CVR-CCR in the ACA territory (0.13-0.3, p=0.019) and CBF-CCR in the PCA territory (0.93-0.96, p=0.0039). Conclusion: Combined revascularization surgery with single bypass to the motor area improved hemodynamics in the primary targeted MCA territory and in the ACA and PCA territories among patients with preoperative hemodynamic impairment.