ABSTRACT
BACKGROUND: Cerebral dysfunction is common after cardiac surgery and probably related to embolic phenomena, but the etiological mechanisms have not been elucidated. The aim of this study was to assess whether a possible neuron loss could be detected by single photon emission computer tomography (SPECT) estimation of benzodiazepine receptor density. In addition, we correlated the findings with neuropsychological test results. METHODS: We included 15 elderly patients undergoing coronary artery bypass surgery. Neuropsychological testing was performed before surgery and postoperatively at discharge from hospital and after 3 months using a neuropsychological test battery. SPECT was performed before surgery and after 3 months using the iomazenil bolus/infusion technique, and the benzodiazepine receptor density was calculated for the frontal, parietal, temporal, and occipital cortex. RESULTS: Cognitive dysfunction was found in 46.7% at discharge from hospital and in 6.7% after 3 months. A significant decrease in the estimated density of neurons was found in the frontal cortex, but no significant correlation was found between cognitive dysfunction and SPECT findings. CONCLUSIONS: Neuron loss was detectable in the frontal cortex, but the decrease did not correlate with neuropsychological test results.
