A novel clinical and imaging based score for predicting outcome prior to endovascular treatment of acute ischemic stroke.

Abstract

Outcome after stroke intervention remains disappointing, with only 30-50% of patients having a good outcome at 90 days. We sought to identify important outcome prognosticators. All consecutive patients that presented with an acute anterior circulation ischemic stroke, with adequate CT perfusion imaging, and that underwent emergency endovascular treatment at two centers between January 1, 2009 and November 2011, were retrospectively reviewed. Investigators estimated the percentage of the total ischemic tissue that had decreased cerebral blood volume (CBV) compared with the total area with elevated time to peak (the penumbra). Multivariate regression analyses were performed to identify variables with prognostic significance and a scoring system was created. 163 patients underwent endovascular treatment for acute ischemic stroke. Outcome data were available in 147 patients (90.2%). A good outcome (modified Rankin Scale score 0-2) occurred in 64 patients (43.5%). Age, National Institutes of Health Stroke Scale (NIHSS) score and per cent decreased CBV scores were the only variables that predicted prognosis on multivariate analyses. A score was created (NAV score-NIHSS, age, volume) that awards points based on these three factors: 2 points for an NIHSS score of ≥ 15, 1 point for age ≥ 70 years, and 1 point for decreased CBV of ≥ 50%. The NAV score was strongly correlated with overall outcome (p<0.01): scores of 0, 1, 2, 3, and 4 were associated with 84%, 50%, 36%, 25%, and 8% chance of a good outcome at 90 days. We introduced a simple three factor scoring system to help predict outcome in patients deemed candidates for intra-arterial acute ischemic stroke intervention.