# Effect of Carotid Stenosis Severity on Patterns of Brain Activity in Patients after Cardiac Surgery
## 2 Materials and Methods  
### Subjects  
This study was a prospective, observational cohort investigation. From a cohort of patients who underwent on-pump coronary surgery in the clinic of the Research Institute for Complex Issues of Cardiovascular Diseases, a sample of 140 subjects was selected. All of the patients met the study criteria and signed an informed consent form. The isolated CABG group consisted of 86 patients, 29 of whom had unilateral CA stenoses of less than 50%. The CABG+CEA group were divided into two groups: the group of left-sided CEA+CABG (n = 30) and the group of right-sided CEA+CABG (n = 24) (see Figure 1). Figure 1: Overview of the study design. The inclusion criteria were as follows: Aged between 45 and 74 years and elective isolated on-pump CABG or combined CABG and CEA. Only right-handed subjects were included in the study to avoid any influence on cognitive status and EEG data regarding the factor of laterality. The exclusion criteria were the presence of pathological changes in the central nervous system, as indicated by the results of multi-layered spiral computed tomography; depressive symptoms, as identified by the Beck Depression Inventory (BDI-II) (sum scores \(\geq\) 8); dementia, as indicated by the Mini-Mental State Examination (MMSE) (sum scores \(\leq\) 24) and Frontal Assessment Battery (FAB) (sum scores \(\leq\) 11); life-threatening arrhythmias; functional class IV heart failure, according to the New York Heart Association (FC NYHA IV) guidelines; chronic obstructive pulmonary disease; malignant pathology; diseases of the central nervous system; brain injury. Patients receiving anxiolytic therapy were also excluded from the study. All patients underwent standardized physical, neurological, and instrumental examinations. The examiners were blind to the cognitive status of the patients. The severity of the coronary lesions was assessed using the findings of coronary angiography (Innova 3100; GE Medical Systems, Carrollton, TX, USA). Carotid artery ultrasound and echocardiography with estimation of the left ventricular ejection fraction (LVEF) were performed with the Vivid 7 ultrasound machine (GE Medical Systems). The patients received baseline and symptomatic therapy before and after surgery, consistent with the general principles of treatment for the patients with CAD, chronic heart failure, and hypertension (National Recommendations, 2020) (see Table 1). All surgical interventions in patients of the isolated CABG and CABG+CEA groups with the use of cardiopulmonary bypass, normothermia and 25-30% hemodilitution were \begin{table}
\begin{tabular}{l c} \hline \hline
**Variable** & **Value** \\ \hline Age, years, Me (Q25; Q75) & 59 (56; 64) \\ \hline Mini-mental state, scores, & \\ Me (Q25; Q75) & 27 (26; 28) \\ Frontal assessment battery, scores, Me (Q25; Q75) & 16 (15; 17) \\ BDI-II, scores, Me (Q25; Q75) & 3 (2; 4) \\ \hline Educational attainment, years, n (\%) & 101 (72) \\
8–10 & 39 (28) \\ \(\geq\)15 & \\ \hline Functional class of angina, n (\%) & \\ I-II & 94 (67) \\ III & 46 (33) \\ \hline Functional class NYHA, n (\%) & 109 (78) \\ I-II & 31 (22) \\ History of myocardial infarction, n (\%) & 104 (74) \\ Fraction of left ventricle ejection, \%, Me (Q25; Q75) & 58 (54; 62) \\ Type 2 of diabetes mellitus, n (\%) & 48 (34) \\ \hline Carotid arteries stenoses, n (\%) & 29 (21) \\ One-sided \(\leq\)50\% & 29 (21) \\ One-sided 70–99\% & 7 (5) \\ Two-sided \(\geq\)50\% & 47 (34) \\ \hline History of stroke, n (\%) & 15 (11) \\ Cardiopulmonary bypass time, min, Me (Q25; Q75) & 90 (83; 97) \\ Aorta cross-clamping time, min, Me (Q25; Q75) & 68 (56; 50) \\ \hline Medication, n (\%) & 124 (89\%) \\ ACEi & 94 (67\%) \\ Station & 137 (98\%) \\ Beta-blockers & 135 (96\%) \\ Antiplatelet drugs & 59 (42\%) \\ CCB & 23 (16\%) \\ \hline ACLi, angiotensin-converting enzyme inhibitor; CCB, calcium channel blockers, NYHA, heart failure by the New York Heart Association. & \\ \hline \hline \end{tabular}
\end{table}