Serum S100β after complex aortic surgery: The effects of hypothermic circulatory arrest

Backgound Neuropsychological morbidity has persistently clouded the success of corrective cardiac surgery. Hypothermic total circulatory arrest (TCA) may expose patients to a greater cerebral insult than that of cardiopulmonary bypass (CPB) alone. This study characterises serum S100β, present in high concentrations in astroglial cells, levels in patients undergoing aortic surgery with or without TCA, using S100β as a marker for cerebral injury. Methods 26 patients underwent aortic surgery with or without TCA. Serial blood samples were taken and the resultant serum stored for batch analysis. S100β was measured, in duplicate, using a radioimmunometric assay. Results There were significant elevations in serum S100β concentrations in all patients compared to preoperative levels, reaching peak levels at skin closure. S100β rises were greater in the TCA group at all time points and persisted for longer. Significant correlations between TCA time and S10β concentrations were present at 5 hours (r = 0.59, p = 0.035) and 24 hours (r = 0.66, p = 0.015) postoperatively. Conclusions (i) S100β elevations were significantly higher in patients who had TCA. (ii) TCA time correlates with S100β levels 5 hours and 24 hours after surgery. (iii) This study raises the suspicion that greater cerebral injury occurs in patients undergoing TCA than without.