Predictive Value of the Hemorrhage After Thrombolysis Score for Tissue Plasminogen Activator-Related Intracranial Hemorrhage: Emergency Department Cohort Study.

BACKGROUND: Intravenous tissue plasminogen activator (tPA) improves outcomes in acute ischemic stroke but carries a risk of intracranial hemorrhage, particularly parenchymal hematoma (PH), which is associated with poor prognosis. Early risk stratification remains clinically important. OBJECTIVE: To evaluate the diagnostic performance of the Hemorrhage After Thrombolysis (HAT) score in predicting PH following intravenous tPA in the emergency department. METHODS: This secondary analysis included a single-center retrospective cohort conducted between October 2023 and February 2025. Adult patients with acute ischemic stroke treated with intravenous tPA within 4.5 h were included. Baseline clinical, laboratory, and imaging data were collected. The primary outcome was PH on 24-h cranial computed tomography. Diagnostic performance was assessed using receiver operating characteristic analysis, with the optimal cutoff determined by the Youden index. RESULTS: A total of 120 patients were included (mean age 70.2 ± 13 years; 57.5% male). PH developed in 11 patients (9.17%). HAT scores were significantly higher in the PH group (p < 0.001). The HAT score showed good discriminative performance for PH (area under the curve [AUC]: 0.871), with an optimal cutoff of 1 (sensitivity 82.6%, specificity 90.9%). For overall hemorrhagic transformation, performance was also good (AUC: 0.786). PH was associated with increased mortality and morbidity. CONCLUSION: The HAT score demonstrates good diagnostic performance for predicting PH after thrombolysis. It may serve as a practical tool for risk stratification and post-treatment monitoring in the emergency department.