The iScore Predicts Clinical Response to Tissue Plasminogen Activator in Korean Stroke Patients

Abstract

Background: Despite substantial differences in clinical features between Asian and Western stroke patients, there are no published prognostic tools validated in an Asiatic population for thrombolytic therapy. We assessed the ability of the iScore to predict the clinical response after intravenous thrombolysis with tissue plasminogen activator (tPA) in a Korean stroke population. Methods: We applied the iScore to eligible participants in the nationwide multicenter stroke registry in Korea. Main outcome measures were poor functional outcome defined as having a modified Rankin Scale score 3-6 and death at 3 months. Symptomatic intracranial hemorrhage (sICH) was evaluated as a safety outcome. C statistic was calculated to assess performance of iScore. Results: Among 4760 patients with an acute ischemic stroke, 622 (13.1%) received tPA, 548 patients had complete information for the analysis. C statistics for poor functional outcome and death at 3 months were .813 (95% confidence interval [CI]: .778-.848) and .820 (95% CI: .769-.872), respectively. Overall, there was a high correlation between observed and expected outcome for poor functional outcome (Pearson correlation coefficient, r = .982) and for death at 3 months (r = .950) at the risk score level. An iScore of 180 or more was associated with a more than 2 times risk of poor functional outcome and about 6 times risk of death at 3 months. There was an interaction between the iScore and tPAfor a poor functional outcome (P value for the interaction, .001). We found a gradient effect in the incident risk of sICH with the iScore. Conclusion: The iScore reliably predicts stroke outcomes after tPA in Asiatic population.