ABSTRACT NUMBER: ESOC2026A948 PROGNOSTIC UTILITY OF VENOUS OUTFLOW PARAMETERS IN PREDICTING FUTILE RECANALIZATION IN ACUTE ISCHEMIC STROKE PATIENTS UNDERGOING ENDOVASCULAR THERAPY

Abstract Background and aims Endovascular therapy(EVT) is the standard of care for acute ischemic stroke(AIS) with large-vessel occlusion(LVO).Despite successful reperfusion, 54% of patients experience futile recanalization(FR), resulting in large infarcts and severe disability. Cerebral blood flow operates as a circuit, and venous filling time reflects collateral efficiency. We hypothesized that venous outflow patterns on initial imaging could predict FR risk.and aimed to evaluated the prognostic value of venous outflow parameters in AIS patients undergoing EVT. Methods We retrospectively analyzed consecutive patients with proximal MCA occlusion who achieved successful thrombectomy(TICI 2b–3) between January 2021 and December 2023. Data were extracted from an ongoing prospective stroke registry.Venous outflow was assessed anatomically using the Collateral-Venous-Outflow-Score(COVES) from CTA and functionally using CTP venous Time-to-Peak(TTP) attenuation for the internal cerebral and Labbé veins.Outcomes included final infarct volume, hemorrhagic transformation, mortality, and 90-day NIHSS and mRS. Results Of 232 EVT-treated AIS patients, 107 met inclusion criteria (age 72.4; 55.1% female). Exclusions were due to posterior circulation strokes, distal occlusions, inadequate or missing imaging, transfers, and failed thrombectomies. Baseline characteristics were similar across venous outflow groups. Multivariable models adjusted for age, sex, NIHSS, and ASPECTS identified COVES(p=0.002), NIHSS(p=0.01), and ASPECTS(p=0.01) as independent predictors of small infarct volume(<20 mL), explaining 34% of variance. No significant associations were found for CTP-derived measures. Conclusions Anatomical venous outflow on CTA independently predicts infarct size in AIS patients undergoing EVT. Routine venous assessment may improve patient selection and outcomes in the large-core thrombectomy era. Conflict of interest Nothing to disclose Figure 1 - belongs to Methods Table 1 - belongs to Results Figure 2 - belongs to Conclusions