Improving the predictive accuracy of recanalization on stroke outcome in patients treated with tissue plasminogen activator

Background and Purpose-Although early recanalization is a powerful predictor of stroke outcome after thrombolysis, some stroke patients remain disabled despite tissue plasminogen activator (tPA)-induced recanalization. Therefore, we sought to investigate whether the predictive accuracy of early recanalization on stroke outcome is improved when combined with clinical and radiological information. Methods-We evaluated 177 patients with nonlacunar strokes in the middle cerebral artery (MCA) treated with intravenous tPA who were followed up during 3 months. Transcranial Doppler monitoring of recanalization was conducted during the first hours after tPA administration. The relative contribution of clinical, transcranial Doppler, and radiological information on stroke outcome was evaluated. We used logistic regression to derive a predictive model for good outcome (modified Rankin Scale score less than or equal to2) after thrombolysis. Results-Median National Institutes of Health Stroke Scale (NIHSS) score before tPA was 16. At 3 months, 87 patients (49.2%) became functionally independent (modified Rankin Scale score less than or equal to2). In a logistic regression model, degree of recanalization within 300 minutes (P<0.001), proximal MCA occlusion (P<0.001), baseline NIHSS score (P=0.0013), systolic blood pressure (P=0.0116), and early ischemic changes on CT (P=0.0253) independently predicted outcome at 3 months. A 5-item score was developed on the basis of the factors significantly associated with stroke outcome in the logistic regression (total score range, 0 to 7). The likelihood of good outcome at 3 months was 0.82 (95% CI, 0.72 to 0.92) in patients who scored 0 to 2, 0.51 (95% CI, 0.36 to 0.66) in those who scored 3 to 4, and 0.15 (95% CI, 0.05 to 0.25) in those who scored 5 to 7 points. Conclusions-The combination of clinical, radiological, and hemodynamic information predicts with a high accuracy long-term stroke outcome during or shortly after intravenous tPA administration.