Abstract W P107: Predictors of Outcome in Patients With Acute M2 Occlusion

Abstract

Background: Limited information is available regarding the outcomes after distal middle cerebral artery stroke. To gain a better understanding, the aim of our study was to assess for factors associated with outcome following M2 middle cerebral artery occlusion infarcts. Methods: We retrospectively reviewed admission computed tomography (CT)-angiography (CTA) of consecutive acute ischemic stroke patients admitted to a single academic center from January 2010 to August 2012. Only patients with isolated M2 occlusion (defined as an occlusion distal to the bifurcation and proximal to further division) were included. We assessed for factors associated with a good 90-day outcome (modified Rankin Scale [mRS] score ≤2). Factors associated with an mRS ≤2 in univariable analyses (p<0.05) were entered into multivariable logistic regression analysis. Admission National Institutes of Health Stroke Scale (aNIHSS), age, and infarct volume were also entered as dichotomized variables. Receiver operating characteristic (ROC) curves were plotted to determine the optimal aNIHSS score, infarct volume, and age cut points predicting an mRS ≤2. Optimal thresholds were determined by maximizing Youden’s index. Results: 90 patients with isolated M2 occlusions were included in final analyses. Of these, 69% had a 90-day mRS ≤2. Age ≤80 years (OR 0.37, 95%-CI 0.003-0.416, p=0.008), aNIHSS ≤10 (OR 0.05, 95%-CI 0.009-0.36, p=0.002), and infarct volume <27 ml (OR 0.009, 95%-CI 0.001-0.15, p=0.001) were independent predictors of a good 90-day outcome. Entering age, aNIHSS, and infarct volume as continuous variables did not meaningfully change these results. Notably, 20% patients (64% of those with a poor outcome) had died by 90-days. We then repeated all analyses for predictors of 90-day mortality. This analysis indicated that age ≤80 years (OR 4.7, 95%-CI 1.25-18, p=0.02) and infarct volume <26 ml (OR 7.3, 95%-CI 1.4-38.5, p<0.001) were independently associated with 90-day mortality. Conclusion: The majority of patients with isolated M2 occlusion strokes have a good 90-day outcome, which is predicted by younger age, lower aNIHSS, and smaller infarct size. Further investigations are required to identify specific factors predicting death in this patient population.