The usefulness of the Kurashiki Prehospital Stroke Scale in identifying thrombolytic candidates in acute ischemic stroke

Purpose: The severity of a stroke cannot be described by widely used prehospital stroke scales. We investigated the usefulness of the Kurashiki Prehospital Stroke Scale (KPSS) for assessing the severity of stroke, compared to the National Institutes of Health Stroke Scale (NIHSS), in candidate patients for intravenous or intraarterial thrombolysis who arrived at the hospital within 6 hours of symptom onset. Materials and Methods: We retrospectively analyzed a prospective registry database of consecutive patients included in the Emergency Stroke Therapy program. In the emergency department, the KPSS was assessed by emergency medical technicians. A cutoff KPSS score was estimated for candidates of thrombolysis by comparing KPSS and NIHSS scores, as well as for patients who actually received thrombolytic therapy. Clinical outcomes were compared between patients around the estimated cut-off. The independent predictors of outcomes were determined using multivariate logistic regression analysis. Results: Excellent correlations were demonstrated between KPSS and NIHSS within 6 hours (R=0.869) and 3 hours (R=0.879) of hospital admission. The optimal threshold value was a score of 3 on the KPSS in patients within 3 hours and 6 hours by Youden's methods. Significant associations with a KPSS score ≥3 were revealed for actual intravenous administration of tissue plasminogen activator (IV-tPA) usage [odds ratio (OR) 125.598; 95% confidence interval (CI) 16.443-959.368, p<0.0001] and actual IV-tPA or intra-arterial urokinase (IA-UK) usage (OR 58.733; 95% CI 17.272-199.721, p<0.0001). Conclusion: The KPSS is an effective prehospital stroke scale for identifying candidates for IV-tPA and IA-UK, as indicated by excellent correlation with the NIHSS, in the assessment of stroke severity in acute ischemic stroke.