Intraoperative application of FFR pressure wire and FLOW800 imaging as predictors of postoperative cerebral perfusion abnormalities in Moyamoya disease

Objective To evaluate whether intraoperative fractional flow reserve (FFR) pressure wire measurements combined with FLOW800 imaging analysis effectively predict postoperative cerebral perfusion abnormalities following superficial temporal artery to middle cerebral artery (STA–MCA) bypass surgery in patients with Moyamoya disease (MMD). Methods A retrospective analysis was conducted on 26 patients diagnosed with MMD who underwent STA–MCA bypass at our institution between November 2023 and January 2025. Intraoperative graft pressures were assessed using FFR pressure wires. Concurrently, FLOW800 imaging provided quantitative microcirculatory parameters, including delay time (DT), flow velocity, rise time (RT), and fluorescence intensity. Postoperative cerebral perfusion-related complications were documented. ROC analyses were reported with 95% confidence intervals to evaluate the predictive value of intraoperative parameters. Results Postoperative cerebral perfusion abnormalities occurred in 9 out of 26 patients (34.6%). Among them, 3 patients (11.5%) had diffusion-weighted MRI (DWI)-confirmed acute ischemic lesions (major complications), whereas the remaining 6 patients experienced transient neurological symptoms that completely resolved within 2 weeks to 1 month without radiographic infarction. A higher pressure gradient across the bypass graft (ΔP) and prolonged rise time (RT) in the proximal recipient artery significantly correlated with postoperative perfusion abnormalities ( p < 0.05). A ΔP cutoff >32 mmHg showed a sensitivity of 77.8% and a specificity of 64.7%. The combined predictive capability of ΔP and RT yielded an area under the receiver operating characteristic (ROC) curve (AUC) of 0.82 (95% CI, 0.61–0.99), surpassing the predictive value of either parameter alone (AUC 0.79 for ΔP and 0.79 for RT). Conclusions Intraoperative monitoring with FFR pressure wire combined with FLOW800 imaging may help identify MMD patients at increased risk of early postoperative cerebral perfusion abnormalities after STA–MCA bypass. The integration of ΔP and RT appears to improve predictive accuracy and may support perioperative risk stratification, although larger prospective studies are required before routine decision-making can be recommended.