Predictive value of S-100β and neuron-specific enolase serum levels for adverse neurologic outcome after cardiac surgery

Objectives: The aim of this study was to evaluate the time course of S-100 beta and neuron-specific enolase serum levels after cardiac surgery and their clinical relevance in predicting postoperative adverse neurologic outcomes; the 2 proteins are only released in peripheral blood in association with nervous system lesions. Methods: We neurologically assessed 190 consecutive patients undergoing elective cardiac operations for coronary artery bypass (n = 147), valve replacement (n = 29), or both (n = 14), before as well as after the operation. Postoperative outcome was classified as type I (uncomplicated), type II (confusion, agitation, disorientation, or epileptic seizures), or type III (stroke, stupor, or coma). Levels of S-100 beta and neuron-specific enolase were evaluated in venous blood samples drawn preoperatively and then daily in the first 5 postoperative days. Results: Levels of S-100 beta and neuron-specific enolase differed significantly among the 3 groups (type III > type II > type I) throughout the postoperative period and had a diagnostic specificity and specificity of 89% and 79%, respectively, in identifying patients, with type III outcome. S-100 beta (but not neuron-specific enolase) levels were identified as significant independent predictors for type II and III outcomes (odds ratio 16.2, P <.0004). The same was true for duration of cardiopulmonary bypass (odds ratio 1.02, P <.006). Conclusions: Serum levels of S-100 beta are reliable markers for adverse neurologic outcomes after cardiac surgery.