Abstract WP22: A Scoring System Based on Age and DWI Volume Predicts Poor Functional Outcome Following Endovascular Treatment for Acute Ischemic Stroke
Background: The Houston IAT (HIAT) score predicts poor outcome following endovascular stroke therapy based on clinical variables (age, serum glucose, and NIHSS score). We aimed to validate the HIAT score in an independent cohort of patients treated with endovascular therapy (DEFUSE 2) and determine if prediction of poor outcome could be improved by including neuroimaging variables in the prediction score.
Methods: Patients enrolled in the DEFUSE 2 study had a clinical diagnosis of acute ischemic stroke and underwent MRI prior to endovascular treatment. Poor functional outcome was defined as a modified Rankin Scale score of 4 to 6 at day 90. The relationship between baseline clinical and neuroimaging variables and poor functional outcome was assessed using univariate and multivariate logistic regression. Statistically significant variables in the multivariate model were used to create a new scoring system. We evaluated the new scoring system and the HIAT score using ROC analysis.
Results: One hundred and ten patients were included in the analysis; forty-two patients had a poor functional outcome. Validation of the HIAT score demonstrated similar ROC properties in the DEFUSE 2 cohort (AUC=0.69) compared to the Houston derivation cohort (AUC=0.73). In DEFUSE 2, age (p=0.001), baseline DWI volume (p=0.09), baseline NIHSS score (p=0.03) and hypertension (p=0.003) were associated with poor functional outcome in univariate analysis. In multivariate analysis, age (p<0.001) and baseline DWI volume (p=0.03) were independent predictors of poor functional outcome. Based on this we developed a new scoring system with a maximum of 3 points awarded for age (0 points, < 55; 1 point, 56-69; 2 points, 70-79; 3 points, ≥ 80) and a maximum of 1 point awarded for baseline DWI volume (0 points, volume ≤ 15 cc; 1 point, volume >15 cc). The percentage of patients with poor functional outcomes increased with the number of points awarded (0% poor outcomes in patients with 0 points, 25% with 1 point, 30% with 2 points, 75% with 3 points, and 89% with 4 points). The AUC for the new scoring system was 0.82.
Conclusion: The new scoring system that incorporates baseline DWI volume and age predicts poor outcome more accurately than a scoring system based on clinical variables alone.
- © 2012 by American Heart Association, Inc.