S100B as a predictor of size and outcome of stroke after cardiac surgery

Background. Stroke after cardiac surgery is a clinical problem with often f atal or disabling outcome. To assess severity and probable outcome in affec ted patients only from clinical and radiological examinations is difficult. The glial-derived protein S100B has been suggested to be a marker of cereb ral ischemia, and increased blood concentrations of S100B have been shown t o correlate with size of lesion and prognosis after stroke. We studied the validity of S100B as a predictor of size of brain lesion and median term ou tcome in a consecutive group of patients suffering from stroke after cardia c surgery. Methods. During a period of 17 months, 20 patients with clinical signs of p ostoperative stroke were investigated with S100B measurement, sampled at 5, 15 and 48 hours after surgery. All. patients were examined with computed t omography or magnetic resonance imaging to confirm the diagnosis, and the s ize of cerebral infarction was estimated from the radiological examinations . The patients were followed up for survival 24 to 39 months after surgery. Results. S100B concentration in blood 48 hours after surgery correlated wit h the size of infarcted brain tissue (r = 0.68, p < 0.001). Nine patients h ad S100B levels exceeding 0.5 <mu>g/L and a 2-year mortality of 78%, wherea s the 11 patients with S100B below 0.5 mug/L had a mortality of 18%. Conclusions. Increased S100B in patients with a stroke following cardiac su rgery correlate with the size of infarcted brain tissue. High S100B levels 48 hours after surgery have a negative predictive value for median term sur vival. (Ann Thorac Surg 2001;71:1433-7) (C) 2001 by The Society of Thoracic Surgeons.