Abstract Number: Esoc2026a1904 Possible Predictors for Hemorrhagic Transformation in Middle Cerebral Artery Stroke Patients Treated With Mechanical Thrombectomy Within and Beyond 6 Hours: A Two-Center Clinical Study

Abstract Background and aims Hemorrhagic Transformation (HT) is a complication after mechanical thrombectomy (MT). We evaluated possible predictors for HT in MCA stroke patients treated within and beyond 6 hours. Methods We retrospectively included 817 MCA stroke patients treated with MT in two centers (603 within 6 hours, 214 beyond 6 hours). Outcomes were HT and symptomatic HT (sHT) at 24 hours. Multivariable logistic regression was performed separately by treatment window. Functional outcome at 3 months was assessed with mRS. Results HT occurred in 110/498(22.1%) patients treated within 6 hours and 54/230(23.5%) beyond 6 hours. Within 6 hours, patients with HT had higher admission glycemia (median 123 vs 114 mg/dL, p=0.002), higher NLR (median 5.5 vs 4.0, p0.001), and higher baseline NIHSS (p0.001). NLR was independently associated with ICH (OR 1.12, 95% CI 1.05–1.19, p0.001). Beyond 6 hours, HT was associated with smoking habit (83.5% vs 67.9%), ischemic heart disease (20.3% vs 10.4%), and higher baseline NIHSS (p0.05). Beyond 6 hours, NLR remained independently associated in multivariable analysis (OR 1.09, 95% CI 1.01–1.18, p=0.030). Higher NLR correlated with worse 3-month mRS in the overall cohort (ρ=0.18, p0.001), within 6 hours (ρ=0.15, p=0.002), and beyond 6 hours (ρ=0.25, p=0.018). sHT was rare beyond 6 hours (4 events). Within 6 hours (24 sHT), poor collateral status was associated with sICH (11.5% vs 4.6%, p=0.017). Conclusions In MCA stroke patients treated with MT, NLR is independently associated with HT in both treatment windows, while sHT is mainly associated with collateral status 6 hours. Conflict of interest Maria Rosaria Bagnato: nothing to disclose