Abstract Number: Esoc2026a2258 Characterizing the Evolution of Hemorrhagic Transformation After Mechanical Thrombectomy

Abstract Background and aims Hemorrhagic transformation (HT) is a significant complication following mechanical thrombectomy (MT). This study aims to characterize the dynamic evolution of HT from the immediate post-procedural period to 24 hours and to identify predictors of its emergence and progression. Methods We included patients from the French MISO and Spanish FURIAS cohort who received MT and achieved mTICI 2B-3 recanalization. HT was evaluated by expert neurologists according to ECASS criteria at two timepoints: early post-MT susceptibility-weighted imaging and 24h computed tomography (final HT). Multivariate models were used to identify independent predictors. Results 150 patients were included (53% women, median age 75 68–82). Early post-MT HT was detected in 26.7% of patients (HI1 10%, HI2 6.7%, PH1 6.7%, PH2 3.3%). By 24 hours, prevalence rose to 39.3% (HI1 11.3%, HI2 12.7%, PH1 8.0%, PH2 7.3%). Among patients without early HT, the incidence of de novo HT at 24 hours was 17.3% while 37.5% of patients with early HT showed further progression. Independent predictors associated with both early and final HT were: admission glycemia (OR 5.32 95% CI 1.53-19.19 and 3.69 1.23-12.11), baseline ischemic core volume (OR 5.75 1.89-19.84 and 7.56 2.39-28.05), and duration of ischemia (OR 1.13 1.06-1.21 and 1.1 1.04-1.18), respectively. Conclusions HT often manifests immediately following MT. Admission glucose, ischemic core volume, and time to recanalization are critical predictors that can identify patients at higher risk for both early emergence and subsequent hemorrhagic progression. Conflict of interest Nothing to disclose Figure 1 - belongs to Results