The stroke-thrombolytic predictive instrument - A predictive instrument for intravenous thrombolysis in acute ischemic stroke

Background and Purpose - Many patients with ischemic stroke eligible for recombinant tissue plasminogen activator (rt-PA) are not treated in part because of the risks and benefits perceived by treating physicians. Therefore, we aimed to develop a Stroke-Thrombolytic Predictive Instrument (TPI) to aid physicians considering thrombolysis for stroke. Methods - Using data from 5 major randomized clinical trials (n = 2184) testing rt-PA in the 0- to 6-hour window, we developed logistic regression equations using clinical variables as potential predictors of a good outcome ( modified Rankin Scale score <= 1) and of a catastrophic outcome (modified Rankin Scale score >= 5), with and without rt-PA. The models were internally validated using bootstrap re-sampling. Results - To predict good outcome, in addition to rt-PA treatment, 7 variables significantly affected prognosis and/or the treatment-effect of rt-PA: age, diabetes, stroke severity, sex, previous stroke, systolic blood pressure, and time from symptom onset. To predict catastrophic outcome, only age, stroke severity, and serum glucose were significant; rt-PA treatment was not. For patients treated within 3 hours, the median predicted probability of a good outcome with rt-PA was 42.9% (interquartile range [IQR] = 18.6% to 64.7%) versus 25.3% (IQR = 9.8% to 46.2%) without rt-PA; the median predicted absolute benefit was 12.5% (IQR = 5.1% to 21.0%). The median probability for a catastrophic outcome, with or without, rt-PA was 15.2% (IQR = 8.0% to 31.2%). The area under the receiver-operator characteristic curve was 0.788 for the model predicting good outcome and 0.775 for the model predicting bad outcome. Conclusions - The Stroke-TPI predicts good and bad functional outcomes with and without thrombolysis. Incorporated into a usable tool, it may assist in decision-making.