S100β after coronary artery surgery: release pattern, source of contamination, and relation to neuropsychological outcome

Abstract

Background. S100β has been suggested as a marker of brain damage after cardiac operation. The aim of this study was to characterize the early S100β release in detail and relate it to neuropsychological outcome.Methods. Three groups of patients were investigated. All patients underwent coronary artery bypass surgery (CABG) with extracorporeal circulation. In group A, 110 patients had sampling of S100β for the first 10 postoperative hours and also underwent neuropsychological testing. In group B, 14 patients were examined for the effect of autotransfusion on S100β levels. Eight patients in group C had their intraoperative bleeding processed with a cell-saving device.Results. Group A had a heterogeneous release pattern with several rapid elevations in S100β concentration. In group B, high concentrations of S100β were found in the autotransfusion blood (range 0.2 to 210 μg/L) with a concurrent elevation of serum S100β levels after transfusion of shed blood. In group C, high levels of S100β were found in the blood from the surgical field (12.0 ± 6.0 μg/L) and decreased (1.1 ± 0.64 μg/L) after wash. Group C had significantly lower S100β values at the end of cardiopulmonary bypass compared to group A (0.53 ± 0.35 μg/L versus 2.40 ± 1.5 μg/L). S100β values were corrected for extracerebral contamination with a kinetic model. With this correction, an association was found between adverse neuropsychological outcome and S100β release in group A (r = 0.39, p < 0.02).Conclusions. A significant amount of S100β is found both in the blood from the surgical field and in the shed mediastinal blood postoperatively. Infusion of this blood will result in infusion of S100β into the blood and interfere in the interpretation of early systemic S100β values.