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.

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.

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.

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.

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.