Background: S100 protein has been suggested to be a serum marker for cerebral complications after cardiac operation and extracorporeal circulation. The aim of this study was to characterize the S100 release pattern after extracorporeal circulation in 515 consecutive patients undergoing coronary artery bypass grafting.
Methods: Clinical variables and outcome were prospectively registered. The cerebral outcome was determined by clinical examination. S100 was measured at the end of extracorporeal circulation, and after 5, 15, and 48 hours.
Results: After operation, 13 patients had stroke, 12 had delayed awakening, and 17 had encephalopathy. Early S100 release, immediately after extracorporeal circulation, was associated with age and perfusion time, but not with cerebral outcome. However, S100 release after 5 to 48 hours was associated with cerebral complications and risk factors for such outcome. Patients with stroke had higher S100 levels after 15 to 48 hours. A subset of patients with renal failure had overall higher S100 levels at 5 hours.
Conclusions: Early and late S100 release indicate different mechanisms for release and emphasizes the potential power of this new biochemical marker for cerebral damage.