Exploring the Impact of Hemoglobin on Cerebral Blood Flow in Arterial Territories and Surgical Outcomes: Potential Implications for Moyamoya Disease Treatment.

Background: Changes in levels of hemoglobin would result in alterations of cerebral blood flow (CBF). However, the impact of hemoglobin on CBF in moyamoya disease (MMD) remains largely unknown. This study sought to determine whether CBF would be influenced by hemoglobin before surgical revascularization and to analyze the relationships between hemoglobin and CBF with clinical outcome after surgery in patients with MMD.

Methods and results: We prospectively enrolled adult patients with MMD undergoing surgical revascularization between June 2020 and December 2022. Preoperative CBF was measured in the territories of anterior, middle, and posterior cerebral arteries (ACA, MCA, and PCA, respectively) using 3-dimensional pseudo-continuous arterial spin labeling magnetic resonance imaging. Clinical outcome at 1 year after surgery was evaluated using the modified Rankin Scale. A total of 60 patients with MMD were included, with 25% (n=15) experiencing unfavorable outcomes. Patients with MMD exhibited lower CBF (ACA: P=0.007; MCA: P<0.001; PCA: P=0.014), compared with healthy controls (n=40). Hemoglobin was negatively and significantly associated with CBF (ACA: β=-0.45, P<0.001; MCA: β=-0.38, P<0.001; PCA: β=-0.54, P<0.001). CBF rather than hemoglobin was significantly related with clinical outcome (ACA: P<0.001; MCA: P<0.001; PCA: P=0.001), and CBF showed high discrimination in predicting clinical outcome (ACA: area under the curve, 0.84; MCA: area under the curve, 0.84; PCA: area under the curve, 0.80).

Conclusions: Our findings demonstrate that hemoglobin significantly influences CBF, and CBF has a high predictive value for clinical outcome in MMD. The optimal hemoglobin level before surgical revascularization should be further investigated.