Efficacy and Safety of Endovascular Treatment for HIR- and Collateral-Screened Ultra-Long Window Anterior Circulation LVO: A Prospective Cohort Study.

This study investigated the clinical value of combined hypoperfusion intensity ratio (HIR) and collateral evaluation for patient selection and prognostic assessment in endovascular therapy (EVT) among anterior circulation large vessel occlusion (LVO) patients within the 6-24 h extended time window. This prospective cohort analysis enrolled 152 LVO patients treated with EVT between January 2022 and June 2024. HIR was defined as the volume ratio of Tmax >10 s to Tmax >6 s hypoperfusion. Collateral status was assessed using the Tan scale, with scores ≥3 classified as favorable. According to the HIR cutoff (≤0.4) and collateral status, patients were divided into four subgroups: Group A (dual favorable), Group B (favorable HIR/poor collaterals), Group C (poor HIR/favorable collaterals), and Group D (dual unfavorable). All participants received standard EVT and adjunct medical therapy for comparative outcome analysis. Groups A (n = 42), B (n = 38), C (n = 35), and D (n = 37) differed significantly in baseline stroke severity and perfusion parameters, with Group D presenting larger ischemic cores, extensive hypoperfusion, and higher NIHSS scores (P < 0.05). Group A achieved the highest 90-day favorable functional rate (69.0%), alongside minimal infarct progression and superior reperfusion (88.1%) (P < 0.001). Favorable HIR (OR = 3.274, P = 0.002) and collateral status (OR = 3.516, P = 0.001) were independent protective factors. The combined model (AUC = 0.84) exhibited better predictive performance than single-index evaluation. Group A also had lower sICH and 90-day mortality than Group D (P < 0.05). Combined HIR and collateral assessment offers a feasible imaging stratification approach for ultra-long-window LVO patients. Dual favorable imaging features predict favorable post-EVT efficacy and safety, assisting individualized clinical decision-making for delayed EVT candidates.