Full Length ArticleAcceleration of blood flow as an indicator of improved hemodynamics after indirect bypass surgery in Moyamoya disease

•Mean velocity (MV) and resistance index (RI) were used as ultrasonography markers.•MV was increased in the STA main trunk and branches at 3 months after EDAS.•RI was decreased at 14 days after EDAS.•MV and RI time-courses differed in subgroups of patients divided by EDAS outcome.

Objective: The ultrasonography findings in the superficial temporal artery (STA) in Moyamoya disease patients treated with indirect bypass remain unclear. We evaluated the time-related changes in ultrasonography findings of the STA main trunk and branches in patients with Moyamoya disease who underwent encephalo-duro-arterio-synangiosis (EDAS).Patients and methodsPatients (n = 21, 30 sides) with Moyamoya disease who underwent EDAS at Fukuoka University Hospital were prospectively registered between 2008 and 2015. EDAS using the frontal and parietal branches of the STA was adopted in an indirect bypass procedure. Mean velocity (MV) and resistance index (RI) were used as ultrasonography markers, and their changes over time in the STA main trunk and branches were assessed.ResultsThere was a significant increase in MV in both the STA main trunk (p = 0.001) and branches (frontal: p = 0.005, parietal: p = 0.003) at 3 months after EDAS, whereas there was a decrease in RI at 14 days after EDAS (main trunk: p < 0.001, frontal: p < 0.001, parietal: p = 0.014). In subgroup analysis of patients divided by EDAS outcome, compared with before EDAS, there were significant differences at 3 months after EDAS in MV (responders: main trunk: p = 0.002, frontal: p = 0.001, parietal: p = 0.001; non-responders: main trunk: p = 0.093, frontal: p = 0.24, parietal: p = 0.96) and RI (responders: main trunk: p < 0.001, frontal: p < 0.001, parietal: p = 0.006; non-responders: main trunk: p = 0.17, frontal: p = 0.12, parietal: p = 0.17).ConclusionsMeasurement of MV may be useful for predicting outcome at 3 months after EDAS.