Neuron loss after coronary artery bypass detected by SPECT estimation of benzodiazepine receptors.
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.
Rasmussen
Lars S
LS
Department of Anaesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Denmark. lsr@rh.dk
Sperling
Bjørn
B
Abildstrøm
Hanne H
HH
Moller
Jakob T
JT
D000368:Aged; D001925:Brain Damage, Chronic / Q000000981:diagnostic imaging*; D002470:Cell Survival / Q000502:physiology*; D002540:Cerebral Cortex / Q000000981:diagnostic imaging; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000000981:diagnostic imaging; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011963:Receptors, GABA-A / Q000032:analysis*; D015899:Tomography, Emission-Computed, Single-Photon
D011963:Receptors, GABA-A