Electrical Activity Changes and Neurovascular Unit Markers in the Brains of Patients after Cardiac Surgery: Effects of Multi-Task Cognitive Training.

BACKGROUND: There is growing interest in finding methods to enhance cognitive function and comprehend the neurophysiological mechanisms that underlie these improvements. It is assumed that non-pharmacological interventions have better results in cognitive recovery. The aim of this study was to assess the effect of multi-task cognitive training (MTT) on electroencephalographic (EEG) changes and markers of the neurovascular unit in patients undergoing coronary artery bypass grafting (CABG). METHODS: This prospective cohort study involved 62 CABG patients aged 45-75 years, 30 of whom underwent a 5-7-day MTT course. The groups of patients were comparable with respect to baseline clinical and anamnestic characteristics. An EEG study was performed before surgery and 11-12 days after CABG. Markers of the neurovascular unit (S100ß, NSE, and BDNF) were examined at three time points: before surgery, within the first 24 h after surgery, and 11-12 days after CABG. RESULTS: Patients without training demonstrated higher relative theta power changes compared to the MTT patients. The course of MTT was associated with low plasma S100ß concentration but high BDNF levels at the end of the training course. CONCLUSIONS: The theta activity changes and the markers of the neurovascular unit (S100ß, BDNF) indicated that the severity of brain damage in cardiac surgery patients after a short course of MTT was slightly reduced. Electrical brain activity indicators and vascular markers can be informative for monitoring the process of cognitive rehabilitation in cardiac surgery patients.

A Comparison of Two Multi-Tasking Approaches to Cognitive Training in Cardiac Surgery Patients.

BACKGROUND: The multi-tasking approach may be promising for cognitive rehabilitation in cardiac surgery patients due to a significant effect on attentional and executive functions. This study aimed to compare the neuropsychological changes in patients who have undergone two variants of multi-tasking training and a control group in the early postoperative period of coronary artery bypass grafting (CABG). METHODS: One hundred and ten CABG patients were divided into three groups: cognitive training (CT) I (a postural balance task with mental arithmetic, verbal fluency, and divergent tasks) (n = 30), CT II (a simple visual-motor reaction with mental arithmetic, verbal fluency, and divergent tasks) (n = 40), and control (n = 40). RESULTS: Two or more cognitive indicators improved in 93.3% of CT I patients, in 72.5% of CT II patients, and in 62.5% of control patients; CT I patients differed from CT II and control (p = 0.04 and p = 0.008, respectively). The improving short-term memory and attention was found more frequently in the CT I group as compared to control (56.7% vs. 15%; p = 0.0005). The cognitive improvement of all domains (psychomotor and executive functions, attention, and short-term memory) was also revealed in CT I patients more frequently than CT II (46.7% vs. 20%; p = 0.02) and control (46.7% vs. 5%; p = 0.0005). CONCLUSIONS: The CT I multi-tasking training was more effective at improving the cognitive performance in cardiac surgery patients as compared to CT II training and standard post-surgery management. The findings of this study will be helpful for future studies involving multi-tasking training.

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

Background: On-pump coronary artery bypass grafting (CABG) is associated with a high risk of neurological complications in patients with severe carotid stenosis. Moreover, early postoperative cognitive dysfunction (POCD) incidence remains high in patients undergoing simultaneous coronary and carotid surgery. Recent studies have shown that even moderate carotid stenosis (≥50%) is associated with postoperative cognitive decline after CABG. Data on brain health in the postoperative period of simultaneous coronary and carotid surgery are limited. Objectives: This study aimed to analyze early postoperative changes in the cognitive function and patterns of brain electrical activity in patients after simultaneous coronary and carotid artery revascularization. Materials and methods: Between January 2017 and December 2020, consecutive patients were assigned to on-pump CABG with or without carotid endarterectomy (CEA) according to clinical indications. An extended neuropsychological and electroencephalographic (EEG) assessment was performed before surgery and at 7-10 days after CABG or CABG + CEA. Results: A total of 100 patients were included [median age 59 (55; 65), 95% men, MMSE 27 (26; 28)], and among these, 46 underwent CEA. POCD was diagnosed in 29 (63.0%) patients with CABG + CEA and in 32 (59.0%) patients with isolated CABG. All patients presented with a postoperative theta power increase. However, patients with CABG + right-sided CEA demonstrated the most pronounced theta power increase compared to patients with isolated CABG. Conclusion: The findings of our study show that patients with CABG + CEA and isolated CABG have comparable POCD incidence; however, patients with CABG + right-sided CEA presented with lower brain activity.

Beneficial Effects of a Short Course of Physical Prehabilitation on Neurophysiological Functioning and Neurovascular Biomarkers in Patients Undergoing Coronary Artery Bypass Grafting.

This study aimed to evaluate the effects of a short course of physical prehabilitation on neurophysiological functioning and markers of the neurovascular unit in patients undergoing coronary artery bypass grafting (CABG). We performed a prospective randomized study involving 97 male CABG patients aged 45-70 years, 47 of whom underwent a 5-7-day preoperative course of aerobic physical training (PhT). Both groups of patients were comparable with respect to baseline clinical and anamnestic characteristics. An extended neuropsychological and electroencephalographic (EEG) study was performed before surgery and at 7-10 days after CABG. Markers of the neurovascular unit [S100ß, neuron-specific enolase (NSE), and brain-derived neurotrophic factor (BDNF)] were examined as metabolic correlations of early postoperative cognitive dysfunction (POCD) at three time points: before surgery, within the first 24 h after surgery, and 7-10 days after CABG. POCD developed in 58% of patients who underwent preoperative PhT, and in 79.5% of patients who did not undergo training, 7-10 days after CABG. Patients without prehabilitation demonstrated a higher percentage of theta1 power increase in the relative change values as compared to the PhT patients (p = 0.015). The short preoperative course of PhT was associated with low plasma S100ß concentration, but high BDNF levels in the postoperative period. Patients who underwent a short preoperative course of PhT had better cognitive and electrical cortical activity indicators. Markers of the neurovascular unit indicated lower perioperative brain injury after CABG in those who underwent training. A short course of PhT before CABG can decrease the brain's susceptibility to ischemia and reduce the severity of cognitive impairments in cardiac surgery patients. Electrical brain activity indicators and neurovascular markers, such as S100ß and BDNF, can be informative for the effectiveness of cardiac rehabilitation programs.

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.

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

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.

EEG and Clinical Factors Associated with Mild Cognitive Impairment in Coronary Artery Disease Patients.

BACKGROUND: Although an impaired cognitive status in patients with coronary artery disease (CAD) is not rare, the neurophysiological and clinical indicators of mild cognitive impairment (MCI) have been insufficiently investigated so far. METHODS: EEG and neuropsychological testing as well as clinical examination were performed on 122 patients with CAD, who were divided into two groups, those with MCI (n = 60; mean age 57.4 ± 5.81 years) and those without MCI (n = 62; mean age 57.0 ± 5.04 years). Binary logistic regression was used to identify the relationship between EEG and clinical variables and the probability of MCI. RESULTS: Higher theta/alpha ratios, theta1 rhythm power with closed eyes in the frontal and occipital areas of the left hemisphere, and alpha2 rhythm power with eyes open in the frontal areas of the right hemisphere were associated with an increased risk for MCI in CAD patients. A low educational level, type 2 diabetes mellitus, and severe coronary lesions according to the SYNTAX Score (≥23 points) increased the risk for MCI as well. CONCLUSIONS: The findings of our study show that a theta activity increase in frontal and occipital sites, as well as high theta/alpha ratios, may be considered as the earliest EEG markers of vascular cognitive disorders.

Does preoperative mild cognitive impairment predict postoperative cognitive dysfunction after on-pump coronary bypass surgery?

BACKGROUND: Mild cognitive impairment (MCI) may contribute to the development of postoperative cognitive dysfunction (POCD) after coronary artery bypass grafting (CABG). OBJECTIVE: The aim of this study was to investigate the incidence of early and long-term POCD after CABG in coronary heart disease patients with and without preoperative MCI. METHODS: The study enrolled two groups of males with coronary heart disease: 51 without MCI (mean age 56.0 ± 6.42 years) and 50 with MCI (mean age 56.4 ± 5.55 years). Baseline clinical characteristics as well as durations of cardiopulmonary bypass and aortic cross-clamping were similar between the two groups. MCI was defined as a Mini-Mental State Examination score of less than 28. All patients underwent detailed neuropsychological examinations (12 tests) before and 7-10 days and 1 year after surgery. The incidence of early and long-term POCD was estimated on the basis of criteria defined as a 20% decline on 20% of the tests. RESULTS: Early POCD was diagnosed in 72% of cases in patients with MCI and in 79% of those without MCI (p = 0.5; odds ratio [OR] = 0.68; 95% confidence interval [CI] 0.2-2.2). Long-term POCD was diagnosed in 72% of MCI patients and in 70% of non-MCI patients (p = 0.8); OR = 1.08 (95% CI 0.4-2.9). CONCLUSIONS: Our results show that the presence of MCI is not the leading cause of either early or long-term POCD in patients undergoing CABG. Further research should focus on the contribution of important clinical factors, including progression of atherosclerosis and adherence, to post-CABG POCD.

SYNTAX score effect on electroencephalography power dynamics in patients undergoing on-pump coronary artery bypass grafting.

BACKGROUND: The severity of angiographically assessed coronary artery disease may be the factor that influences the degree of brain damage during on-pump surgery. Modern technology such as computed electroencephalography (EEG) that is used to detect signs of brain damage could also be used to determine the advantages and disadvantages of various surgical myocardial revascularization methods in certain categories of patients. The present study investigated EEG power dynamics for 1 postoperative month in patients undergoing on-pump coronary artery bypass grafting (CABG) who were divided into two groups: those with moderate coronary lesions (SYNTAX score ≤ 22, n = 12) and those with severe coronary lesions (SYNTAX score ≥ 23, n = 18). RESULTS: At 7-10 days after CABG, all patients showed theta type 1 rhythm power higher than that seen preoperatively, possibly indicating that brain damage occurred during bypass. At 1 month after CABG, the theta type 1 rhythm power had decreased to the baseline level in patients with SYNTAX scores of ≤22, whereas it had increased in patients with SYNTAX scores ≥23. CONCLUSIONS: SYNTAX scores ≥ 23 are associated with EEG markers of perioperative brain damage during CABG. Careful preoperative assessment, preparation, and more effective intraoperative brain protection are essential for this category of coronary heart disease (CHD) patients.

The Influence of Low and Moderate Carotid Stenosis on Neurophysiologic Status of Patients Undergoing on-pump Coronary Artery Bypass Grafting.

BACKGROUND: Significant (>70%) extracranial stenosis of the internal carotid artery (ICA) is a known risk factor for brain damage in patients with coronary heart disease (CHD) undergoing coronary artery bypass grafting (CABG). There is no clear evidence of the low and moderate ICA stenoses influence on the neurophysiologic status of patients after CABG. This work was aimed at studying the influence ICA stenoses (<50%) on the dynamics of neurophysiologic status in patients undergone CABG. METHODS: We examined neurophysiologic functions and electroencephalograph in CHD patients (N = 45) aged from 45 to 70 years. All patients were divided into two groups: with ICA stenosis (n = 20) and without one (n = 25). RESULTS: It was established that the group ICA stenosis had a negative dynamics of neurophysiologic status 6 months follow-up after CABG compared with patients without stenosis. CONCLUSION: Our results suggest that the presence of low and moderate ICA stenosis is one of the factors affecting the neurophysiologic status of CHD patients. It has been assumed that the patients with ≤50% ICA stenoses constitute a high-risk group for cerebral complications after on-pump CABG.