ABSTRACT NUMBER: ESOC2026A1563 EARLY MEAN ARTERIAL PRESSURE AFTER SYMPTOM ONSET AND HEMORRHAGIC TRANSFORMATION AFTER INTRAVENOUS THROMBOLYSIS

Abstract Background and aims Hemorrhagic transformation (HT) remains a major complication after intravenous thrombolysis (IVT). The prognostic relevance of the earliest blood pressure measured after symptom onset, particularly mean arterial pressure (MAP), is insufficiently defined. Methods We analyzed consecutive IVT-treated ischemic stroke patients at the Special Hospital for Cerebrovascular Diseases “Sveti Sava” during 2024–2025. Blood pressure exposure was defined as the first recorded systolic and diastolic value after symptom onset. Outcomes were assessed on follow-up imaging: any HT (HI, sICH, or SAH vs none) and symptomatic intracerebral hemorrhage (sICH; ECASS III). Patients without follow-up CT were excluded. Multivariable logistic regression evaluated associations of MAP and, secondarily, SBP (per 10 mmHg increase) with outcomes, adjusting for age, admission NIHSS, and onset-to-needle time (OTN; wake-up strokes: midpoint-of-sleep-to-needle). Sensitivity analysis excluded OTN. Results Among 430 IVT-treated patients, 2 were excluded due to missing follow-up CT. Complete-case multivariable models included 353 patients; HT occurred in 15.9% and sICH in 4.2%. Higher MAP was independently associated with any HT (OR 1.25 per 10 mmHg; 95% CI 1.07–1.46; p=0.006) but not with sICH (OR 1.13; 95% CI 0.86–1.48; p=0.376). SBP showed a weaker association with any HT (OR 1.12 per 10 mmHg; 95% CI 1.02–1.22; p=0.018) and no association with sICH. In sensitivity analysis excluding OTN (N=392), the association between MAP and any HT remained robust (OR 1.29; 95% CI 1.11–1.51; p<0.001). Conclusions Elevated MAP measured immediately after symptom onset is associated with increased risk of hemorrhagic transformation after IVT, while no clear association with sICH was observed. Conflict of interest All authors nothing to disclose