Reperfusion Is a Stronger Predictor of Good Clinical Outcome than Recanalization in Ischemic Stroke

Purpose: To assess the predictive value of reperfusion indices, recanalization, and important baseline clinical and radiologic scores for good clinical outcome prediction. Materials and Methods: The study was approved by the local research ethics board. Written consent was obtained from all participants or their caregivers. Baseline computed tomography (CT) perfusion less than 4.5 hours after stroke symptoms, follow-up CT perfusion at 24 hours or less, and 5-7-day magnetic resonance images were obtained for 114 patients. Baseline imaging was assessed blinded to outcome. Recanalization status was determined at follow-up CT angiography. Reperfusion index was calculated on baseline and on follow-up at-risk tissue volume. Kruskal-Wallis, Mann-Whitney rank sum, and Spearman correlation were used for group comparisons and correlation studies. Univariate and multivariate logistic regression tested the association of clinical and imaging parameters with good outcome. Models with and without recanalization and reperfusion were compared by using Akaike information criterion. Results: Reperfusion indices were significantly higher in patients with recanalization than in those without (P < .001). Despite significance of recanalization at univariate analysis, only reperfusion, age, and National Institutes of Health Stroke Scale score were significant after multivariate analysis (P < .01). Time to maximum reperfusion index had the highest accuracy (area under the receiver operating characteristic curve, 0.70) for good outcome, and reperfusion was defined as time to maximum volume of 59% or greater. Patients with reperfusion but no recanalization had significantly lower total infarct volume (P = .001) and infarct growth (P = .004) and had higher salvaged penumbra (P = .009) volumes than patients without reperfusion and recanalization. A final model with reperfusion but not recanalization was the most prognostic model of good clinical outcome. Conclusion: Reperfusion showed stronger association with good clinical outcome than did recanalization. (C) RSNA, 2013