Neurobehavioral outcome prediction after cardiac surgery - Role of neurobiochemical markers of damage to neuronal and glial brain tissue

Background and Purpose-The goal of the present study was to;investigate the predictive value of neurobiochemical markers of brain damage (protein S-10 0B and neuron-specific;enolase [NSE]) with respect to the short- and long-t erm neuropsychological outcomes after cardiac surgery with cardiopulmonary bypass (CPB). Methods-We investigated 74 patients who underwent elective CABG or Valve re placement surgery and who showed no severe neurological deficits after surg ery. Patients were investigated;with a standardized neurological examinatio n and a comprehensive neuropsychological and neuropsychiatric assessment 1 to 2 days before surgery, 3 and 8 days after surgery, and 6 months later. S erial venous blood samples were taken preoperatively and 1, 6, 20, and 30 h ours after skin closure. Protein S-100B and NSE were analyzed with immunolu minometric assays. Results-Patients with severe postoperative neuropsychological disorders sho wed a significantly higher and longer release of neurobiochemical markers o f brain damage. Patients who presented with a delirium according to DSM-III -R criteria 3 days after surgery had significantly higher postoperative S-1 00B serum concentrations. Multivariate analysis (based on postoperative NSE and S-100B concentrations and age of:patients, type of operation, length o f cross-clamp and perfusion time, and intraoperative and postoperative oxyg enation) identified NSE and S-100B concentrations 6 to 30 hours after skin closure as the only variables that contributed significantly to a predictiv e model of the neuropsychological outcome. NSE, but not S-100B, release was significantly higher in patients undergoing valve replacement surgery. Conclusions-Postoperative serum concentrations and kinetics of S-100B:and N SE have a high predictive value with respect to the early neuropsychologica l and neuropsychiatric outcome after cardiac surgery. The analysis of NSE a nd S-100B release might allow insight into the underlying pathophysiology o f brain dysfunction, thus providing a valuable tool to monitor and evaluate measures to improve cardiac surgery with CPB.