The changes of brain electric activity in patients with different severity of coronary atherosclerosis one-year after coronary artery bypass grafting

Aim. To examine the brain electrical activity changes with the quantitative electroencephalogram (qEEG) indicators (the spectral power) in patients at 1 year after on-pump coronary artery bypass grafting (CABG) depending on the severity of the coronary lesions. Methods. 65 patients were included in the study. Before performing CABG, they were divided into two groups depending on the severity of coronary artery disease according to the SYNTAX score: patients with mild coronary artery lesions – SYNTAX ≤22, (n = 28) and patients with severe coronary lesions – SYNTAX ≥ 23, (n = 37). EEG studies were performed in the preoperative period (at days 3–5 before GABG) and 1 year after surgery. Variance analysis with repeated comparisons (ANOVA) was used to compare pre-and postoperative EEG spectral power indicators in five clusters of the right and left hemispheres. Results. Patients with SYNTAX ≥23 had higher theta rhythm power values as compared with patients with SYNTAX ≤22 (p = 0.018) at 1 year after CABG, whereas these groups were comparable before the surgery. In addition, patients with severe lesions of the coronary arteries (SYNTAX ≥23) demonstrated an increase of theta rhythm power at 1 year after surgery in comparison to preoperative values (p = 0.017), this effect was not detected in patients with SYNTAX ≤22. Conclusion .One year after CABG, patients with severe coronary lesions (SYNTAX ≥23), demonstrated qEEG changes that resembled cortical dysfunction, showing significance of severity of coronary atherosclerosis, assessed by the SYNTAX score, as an integral indicator, indirectly characterizing neurophysiological status of patients.