Serum S100β release after coronary artery bypass grafting: roller versus centrifugal pump

Background. Microemboli generated during cardiopulmonary bypass (CPB) are implicated in the cerebral injury seen after coronary artery bypass grafting. Centrifugal pumps generate fewer microemboli than roller pumps. Increased S100β levels have been reported after coronary artery bypass grafting, with levels greater than 1 ng/mL resulting in poorer neuropsychologic outcome. This study investigated the potential neurologic benefits of centrifugal pumps, by using S100β as a marker for cerebral injury. Methods. Thirty-two patients who had coronary artery bypass grafting were randomly assigned to two groups. Serial blood samples (preoperative, end of bypass, 30 minutes, and 2 and 24 hours after cardiopulmonary bypass) were taken and the serum analyzed for S100β using a new immunoluminometric assay. Results. Both groups were matched for age, number of grafts, and cardiopulmonary bypass and cross-clamp times. Postoperative serum S100β levels were significantly higher in both groups than preoperative levels. Peak S100β levels did not correlate with cardiopulmonary bypass time; however, 24-hour S100β levels correlated with intubation time r = 0.40, p = 0.04). There was no significant difference in S100β levels between the groups at any of the time points. Conclusions. S100β levels increased after coronary artery bypass grafting. Centrifugal pumps do not significantly decrease S100β release. Persistently increased S100β levels are associated with longer intubation times.