Utility of the stroke-thrombolytic predictive instrument.

OBJECTIVE The goal of this study was to evaluate the utility of the stroke thrombolytic predictive instrument (s-TPI) in predicting clinical outcome in patients with acute ischaemic stroke treated with intravenous tissue plasminogen activator (t-PA). METHODS The study assessed the external validity of the s-TPI in 301 consecutive stroke patients treated with intravenous t-PA. Clinical outcome was measured with the modified Rankin scale (mRs) at 3 months. The study used the s-TPI to calculate probabilities of a good outcome (mRs 0-1) and a poor outcome (mRs 5-6). We compared these probabilities with the observed outcome using receiver-operator characteristics (ROC) curves and calibration curves. Subgroup analyses for different onset-to-treatment time windows were performed. RESULTS According to the s-TPI, the mean predicted probability of a good and a poor outcome in the validation cohort were 0.45 and 0.17. The area under the ROC curves were 0.80 (4.5-hour time window), 0.82 (3-hour time window) and 0.77 (3-4.5 hours time window) for predicting good outcome, and 0.78 (4.5 hours), 0.80 (3 hours) and 0.74 (3-4.5 hours) for predicting poor outcome. Calibration curves revealed a slight overestimation of probabilities of a good outcome and underestimation of probabilities of a poor outcome. CONCLUSIONS The s-TPI appears to be reasonably valid for predicting outcome after t-PA treatment in daily practice, although a slight overestimation of a good and underestimation of a poor outcome was observed.