Evaluation of serum S100B as a surrogate marker for long-term outcome and infarct volume in acute middle cerebral artery infarction

Background: An easily accessible and valid surrogate marker for interventional stroke trials is needed. Objective: To investigate the usefulness of various S100B serum measures to predict long-term outcome and infarct volume in patients with acute stroke. Design: Inception cohort study. Setting: Tertiary care university hospital Patients: Thirty-nine patients (mean +/- SD age, 69.1 +/- 11.5 years) with acute nonlacunar middle cerebral artery infarction presenting less than 6 hours after symptom onset. Main Outcome Measures: Functional outcome 6 months after stroke (modified Rankin scale score) and final infarct volume on day 7 by means of standardized volumetry of brain images. Serum S100B level was determined at hospital admission and 24, 48, 72, 96, 120, and 144 hours after symptom onset. Results: Single S100B measures obtained 48 and 72 hours after stroke onset demonstrated the highest Spearman rank correlations with modified Rankin scale scores (rho = 0.68 and rho = 0.67, respectively; P <.001) and infarct volume (rho=0.95 and rho=0.94, respectively; P <.001). A 48-hour S100B value of 0.37 mu g/L or less revealed a sensitivity of 0.87 and a specificity of 0.78 in predicting an independent functional outcome. In a multivariate model, S100B emerged as an outcome predictor that was independent of age, sex, stroke severity, etiology, lesion side, and risk factors.