ABSTRACT NUMBER: ESOC2026A397 BLOOD-BRAIN BARRIER DISRUPTION BEFORE INTER-HOSPITAL TRANSFER FOR THROMBECTOMY PREDICTS HEMORRHAGIC TRANSFORMATION

Abstract Background and aims In acute stroke with large vessel occlusion (AIS-LVO), preventive strategies to mitigate hemorrhagic transformation (HT) following endovascular therapy (EVT) are needed. Inter-hospital transfer for EVT offers a unique therapeutic window during which preventive treatments could be administered, allowing sufficient exposure before EVT. We aimed to determine whether blood-brain barrier (BBB) disruption assessed prior to transfer is associated with 24-hour HT. Methods Multicenter retrospective study including AIS-LVO patients transferred from primary to comprehensive stroke centers for EVT assessment, with baseline MR-perfusion imaging performed before transfer. BBB disruption was quantified as the percentage signal change due to gadolinium leakage on perfusion source images. Mean permeability derangement (MPD) was defined as the average of voxels within the ischemic core exhibiting permeability values greater than a prespecified threshold. The primary outcome was any HT on 24-hour follow-up imaging. Results A total of 289 patients were included (median age 74 years, NIHSS 13, core volume 17 mL). HT occurred in 129 patients (45%), including HI1-2 in 24% and PH1-2 in 20%. Median MPD was higher in patients with HT than in those without (5.1% vs 3.0%; p<0.001). In multivariable analysis, elevated MPD was independently associated with HT after adjustment for core volume, glucose, occlusion site, and onset-to-imaging time (aOR 1.21; 95%CI 1.10-1.33; p<0.001). Similar associations were observed for parenchymal hematoma as a secondary outcome. Conclusions BBB disruption on pre-transfer perfusion MRI is strongly associated with 24-hour HT in AIS-LVO patients. Targeted interventions aimed at stabilizing the BBB during transfer warrant investigation in clinical trials. Conflict of interest All authors : nothing to disclose Figure 1 - belongs to Conclusions