Association Between Tissue No-Reflow and Prognosis After successful Recanalization in Endovascular Treatment of Intracranial Atherosclerotic Occlusion: A Post Hoc Subgroup Analysis of the ANGEL-REBOOT Trial

BACKGROUND: No-reflow after successful endovascular treatment (EVT) predicts poor outcomes in acute ischemic stroke (AIS) due to intracranial atherosclerotic stenosis (ICAS), but its optimal evaluation and prognostic value remain unclear. This study assessed computed tomography perfusion (CTP)-defined no-reflow for predicting outcomes in ICAS-related large vessel occlusion (ICAS-LVO). METHODS: This retrospective post hoc analysis included patients from the prospective ANGEL-REBOOT trial with anterior circulation ICAS-LVO, successful eTICI 2b/3 recanalization, and postoperative 24-hour CTP. No-reflow was defined as persistent hypoperfusion (Tmax >4s or >6s) after recanalization. Outcomes included 90-day modified Rankin Scale (mRS) score (poor outcome ≥3) and 24-hour National Institutes of Health Stroke Scale (NIHSS) score. RESULTS: In this exploratory post-hoc analysis, the optimal cohort derived cutoff value for Tmax > 4s hypoperfusion volume was 95.8 mL. Among 64 patients, Tmax >4s hypoperfusion volume ≥95.8 mL best predicted poor 90-day outcome (area under the curve [AUC] 0.75). Larger Tmax >4s volumes correlated with worse 90-day mRS scores (P=0.04) and higher 24-hour NIHSS scores (P=0.006). Tmax >6s (cutoff 9.9 mL, AUC 0.690) only predicted higher 24-hour NIHSS score (P=0.001) but not 90-day outcomes (P=0.12). CONCLUSIONS: Postoperative 24-hour CTP Tmax > 4 s hypoperfusion volume showed a trend toward better prediction of 90-day poor functional outcomes compared with Tmax > 6 s in recanalized ICAS-LVO patients.