Utility of the stroke-thrombolytic predictive instrument

Abstract

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.