The Relationship between s100β and Cerebral Oximetry Trend in Patients Undergoing CABG with Cardiopulmonary Bypass

Background: Coronary artery bypass grafting (CABG) is among the most common cardiac surgery procedures carried out on heart pump. However, there are always risks for potential neurologic and neurocognitive insults in CABG. One of the biomarker of central nervous system (CNS) is s100β that shows damage. Cerebral oximetry using near-infrared spectroscopy (NIRS) developed for CNS monitoring especially in cardiac surgery. This study was designed to find the relationship between serum levels of s100β and cerebral oximetry in CABG patients.Materials and Methods: In an observational study, 44 adult patients (40-75 years) entered the study for elective CABG. Serum levels of s100β were assessed at two times during cardiopulmonary bypass (CPB); i.e. just after aortic clamping and immediately after aortic declamping; while the results were compared with right and left cerebral oximetry readings NIRS. It was measured at baseline, during start of cardiopulmonary bypass (CPB), during aortic clamping, and finally at off-clamping the aorta. Repeated Measures ANCOVA (analysis of covariance), multiple linear regression models and Spearman correlation coefficient with scatter plot were used for data analysis. P value less than 0.05 considered significant.Results: There was no linear correlation between s100β and NIRS according to correlation coefficients. The only positive linear relationship between s100β and right NIRS was observed among patients whose s100β was more than 10 (spearman correlation coefficient= 0.792; P value=0.006).Conclusion: This study failed to demonstrate a relationship between on-CPB NIRS numbers and serum s100β in adult patients undergoing CABG during the bypass interval; further studies are suggested to evaluate potential predictive value of NIRS in brain ischemia related to CABG.