Long-Term Neurophysiological Outcomes in Patients Undergoing Coronary Artery Bypass Grafting

Abstract

Introduction This study aims to evaluate late postoperative neurophysiological outcomes in patients after coronary artery bypass grafting (CABG). Methods Forty-five male patients with stable coronary artery disease aged 45-69 years underwent extended neuropsychological assessment using the software Status PF and electroencephalographical examination 3-5 days before CABG and 5-7 years after CABG. Postoperative decline in cognitive functions was determined by a 20% decrease in the cognitive indicator compared to that at baseline on 20% of the tests included in the Status PF battery. Statistical analysis was performed using the software STATISTICA 10.0. Multiple regression was used to identify demographic, clinical, and electroencephalographical variables associated with adverse cognitive outcomes. Results Cognitive decline was observed in 54% of the patients in the long-term postoperative period. Five to seven years after CABG, all patients have shown an increase in the theta rhythm power compared to the preoperative values, which is most pronounced in the frontal and temporal areas of the right hemisphere ( P =0.04), along with a decrease in the alpha rhythm in the posterior areas of the cortex ( P =0.005). Multiple regression has reported that the main predictors of cognitive impairment are slower mean alpha frequency, decreased theta-2 rhythm with eyes closed in the right temporal area, and increased theta-2 rhythm with eyes open in the left temporal area (F(5.39)=8.81; P <0.00007; adjusted R-squared=0.57). Conclusion Our findings indicate that 54% of the patients suffer from postoperative cognitive decline associated with increased theta and decreased alpha rhythms 5-7 years after CABG.

Intraoperative hyperoxygenation may negatively affect postoperative cognitive functions in coronary artery bypass graft operations: A randomized controlled study

“…14 A neurophysiological study showed that 5-7 years after CABG, 54% of patients experienced postoperative cognitive decline associated with increased theta and decreased alpha rhythms on EEG. 15 A study about longitudinal cognitive performance of patients with CABG showed a two-stage course with early improvement followed by later decline. Long-term cognitive deficit was predicted by early cognitive decline, but not by ischemic brain lesions on magnetic resonance imaging.…”

“…Cerebral perfusion and oxygenation abnormalities that may develop during the perioperative period are significant factors in developing neurological complications 14 . A neurophysiological study showed that 5–7 years after CABG, 54% of patients experienced postoperative cognitive decline associated with increased theta and decreased alpha rhythms on EEG 15 . A study about longitudinal cognitive performance of patients with CABG showed a two‐stage course with early improvement followed by later decline.…”

Cognitive functions and patterns of brain activity in patients after simultaneous coronary and carotid artery revascularization

“…Artifact-free EEG fragments were divided into 2s epochs and underwent Fourier transformations. For each subject, EEG power values were averaged within the theta1 (4–6 Hz) range, taking into account the results of previous studies indicating the diagnostic significance of low-frequency rhythm changes in the detection of postoperative ischemic brain injury (Tarasova et al, 2019 , 2021 ). The next step was the clustering of data recorded in 56 leads into five electrode zones symmetrically in the left and right hemispheres: frontal (F) (Fp1/2, AF3/4, F1/2, Fp3/4, Fp5/6, F7/8), central (C) (FC1/2, FC3/4, FC5/6, C1/2, C3/4, and C5/6), temporal (T) (FT7/8, T7/8, and TP7/8), parietal (P) (CP1/2, CP3/4, CP5/6, P1/2, P3/4, P5/6, P7/8), and occipital (O) (PO3/4, PO5/6, PO7/8, O1/2).…”

“…Electroencephalography (EEG) may be a promising method for obtaining data on specific changes in the brain electrical activity in cardiac surgery patients due to high temporal and moderate spatial resolution. The study of spontaneous electrical activity in the brain in various pathological conditions revealed that neuronal oscillatory systems are widely involved and that such changes are the earliest evidence of subsequent impairment of cognitive functions (Bonanni et al, 2015 ; Engels et al, 2016 ; Tarasova et al, 2021 ). The brain's electrical activity is affected by temperature management during cardiopulmonary bypass, the depth of anesthesia, metabolic disorders, in particular hypo- or hyperglycemia, and impaired cerebral autoregulation (Howard et al, 2012 ; Sutter et al, 2013 ).…”

“…The brain's electrical activity is affected by temperature management during cardiopulmonary bypass, the depth of anesthesia, metabolic disorders, in particular hypo- or hyperglycemia, and impaired cerebral autoregulation (Howard et al, 2012 ; Sutter et al, 2013 ). A number of studies have demonstrated a high diagnostic value of EEG parameters in patients undergoing CABG (Tarasova et al, 2021 ; Trubnikova et al, 2021 ). EEG theta band activity is one of the most sensitive indicators associated with perioperative brain injury.…”