Serum S-100β protein predicts brain injury after hypothermic circulatory arrest in pigs

Abstract

Objective - Serum S-100β protein is suggested to be a neurobiochemical marker of brain injury after cardiac and aortic arch surgery. The aim of the present study was to investigate the predictive value of S-100β protein with respect to histopathological analysis of the brain after a prolonged period of hypothermic circulatory arrest (HCA). Methods - Eighteen pigs (21 to 31 kg) underwent a 75 min period of HCA at 20°C. Serum concentrations of S-100β were assayed in mixed venous blood before and 2, 4, 7 and 20 h after HCA. A semiquantitative post-mortem histopathological analysis scoring all main regions of the brain was carried out in every animal. Results - All animals were stable during and after cardiopulmonary bypass (CPB) and survived at least to the first postoperative day. Ten of the 18 animals survived 7 days after surgery and were electively sacrificed. Animals with severe histopathological injury showed higher serum S-100β protein levels at every time point after HCA. The strongest correlation between the total histopathologic score and serum S-100β levels was found at 7 h after HCA (τ =0.422 and p=0.023). Conclusion - Serum S-100β protein levels correlate with histopathological injury after a prolonged period of HCA in pigs. This finding supports the results of previous studies suggesting the potential accuracy of S-100β in the prediction of brain injury after cardiac surgery.