Cognitive decline after coronary artery bypass grafting is recognized and well-documented. The purpose of this study was to evaluate whether the level of cognitive biomarkers after heart surgery correlate with the development of cognitive dysfunction Concentrations of b-amyloid peptide, tau and S100b in the cerebrospinal fluid were assessed before and after coronary artery bypass grafting, utilizing immuno-assays. A drastic rise in the level of S100b was observed 1 week after the surgery, the mark of a severe cerebral injury. The level of b-amyloid peptide significantly decreased, whereas the concentration of tau markedly increased 6 months postoperatively. These findings clearly demonstrate that changes in biomarkers after heart surgery are similar to that seen in Alzheimer's disease, confirming the cognitive decline after cardiac interventions at the molecular level.