Biomarkers of cerebral injury in cardiac surgery

The present study aims to reveal the changing patterns of cerebral biomarkers and the underlying predictive factors as a consequence of cardiac surgery. Literature retrieval of articles on S100 and S100B of recent 20 years were made in the MEDLINE database, Highwire Press and Google search. Quantitative data of S100 and S100B along with neuron-specific enolase were carefully screened, collected and statistically analyzed. The biomarkers appeared earlier and lasted longer in the cerebrospinal fluid than in the serum. All three biomarkers exhibited a similar kinetic trend in the bloodstream, reaching a peak value at the end of cardiopulmonary bypass (CPB). In adults, serum biomarkers may recover to normal earlier than in pediatrics undergoing a cardiac surgery. The patients undergoing off-pump surgery had the minimal elevations of cerebral biomarkers comparing to all other cardiac surgeries under CPB, low core temperature and/or hypothermic circulatory arrest. In patients with pre- or postoperative neurological disorders, the biomarkers in the serum elevated even before operation and persisted longer time than those without neurological disorders. The serum concentrations of the biomarkers showed direct correlation with CPB duration and core temperature. Cardiac operations may lead to cerebral damage and blood-brain barrier changes, as a consequence of CPB and low core temperature. The cerebral biomarkers including S100, S100B and neuron-specific enolase may precisely reflect the cerebral damages in cardiac surgery. Attention has to be paid to the attenuations of cerebral damage by modifying the surgical conditions of CPB and core temperature.