An Update on Postoperative Cognitive Dysfunction Following Cardiac Surgery

Protecting the Brain While Healing Hearts: The Protective Role of Cognitive Reserve in Cardiac Surgery

OBJECTIVE

One of the most significant complications following coronary artery bypass grafting (CABG) is postoperative cognitive decline (POCD). CABG patients frequently experience considerable postoperative cognitive dysfunction (POCD), including decline in attention, orientation, memory, judgment, and social functioning.

DESIGN

These negative effects may potentially be resolved by a protective factor, cognitive reserve (CR) that has been considered to function as a buffer against the consequences of neuropathology.

SETTING

We explored the frequency of POCD and CR in coronary artery disease patients undergoing CABG. We hypothesized that high levels of CR would protect against POCD after cardiac surgery.

PARTICIPANTS

We assessed 101 patients before surgery, and 4 months after cardiopulmonary bypass surgery with the use of extracorporeal circulation.

MEASUREMENTS

Measures of cognitive functions, CR, anxiety, and depression were included in the assessment.

RESULTS

Each patient was placed in the high (n = 50) or low CR (n = 51) group, based on median split. Chi-square tests effect showed that patients with low CR were more likely to a great extend to demonstrate postsurgical cognitive decline in attention, memory, visuospatial perception and executive functions than patients with high CR upon postsurgery neuropsychological assessment.

CONCLUSIONS

Our results suggest that CR can forecast neuropsychological outcomes of cardiac surgery, recognizing the patients with low CR and help them to participate to interventions programs that could slow cognitive aging or reduce the risk of dementia and enhance their overall postsurgical functional outcome.

Communication Regarding the Myocardial Ischemia/Reperfusion and Cognitive Impairment: A Narrative Literature Review

Coronary artery disease is a prevalent ischemic disease that results in insufficient blood supply to the heart muscle due to narrowing or occlusion of the coronary arteries. Various reperfusion strategies, including pharmacological thrombolysis and percutaneous coronary intervention, have been developed to enhance blood flow restoration. However, these interventions can lead to myocardial ischemia/reperfusion injury (MI/RI), which can cause unpredictable complications. Recent research has highlighted a compelling association between MI/RI and cognitive function, revealing pathophysiological mechanisms that may explain altered brain cognition. Manifestations in the brain following MI/RI exhibit pathological features resembling those observed in Alzheimer's disease (AD), implying a potential link between MI/RI and the development of AD. The pro-inflammatory state following MI/RI may induce neuroinflammation via systemic inflammation, while impaired cardiac function can result in cerebral under-perfusion. This review delves into the role of extracellular vesicles in transporting deleterious substances from the heart to the brain during conditions of MI/RI, potentially contributing to impaired cognition. Addressing the cognitive consequence of MI/RI, the review also emphasizes potential neuroprotective interventions and pharmacological treatments within the MI/RI model. In conclusion, the review underscores the significant impact of MI/RI on cognitive function, summarizes potential mechanisms of cardio-cerebral communication in the context of MI/RI, and offers ideas and insights for the prevention and treatment of cognitive dysfunction following MI/RI.

Post-Operative Delirium and Cognitive Dysfunction in Aged Patients Undergoing Cardiac Surgery: A Randomized Comparison between Two Blood Oxygenators

In elderly patients undergoing cardiac surgery, extracorporeal circulation affects the incidence of post-operative delirium and cognitive impairment with an impact on quality of life and mortality. In this study, a new oxygenator system (RemoweLL 2) was tested against a conventional system to assess its efficacy in reducing the onset of postoperative delirium and cognitive dysfunction and the levels of serum inflammatory markers. A total of 154 patients (>65 y.o.) undergoing cardiopulmonary bypass (CPB) were enrolled and randomly assigned to oxygenator RemoweLL 2 (n = 81) or to gold standard device Inspire (n = 73) between September 2019 and March 2022. The aims of the study were to assess the incidence of delirium and the cognitive decline by neuropsychiatric tests and the MoCa test intra-hospital and at 6 months after CPB. Inflammation biomarkers in both groups were also evaluated. Before the CPB, the experimental groups were comparable for all variables. After CPB, the incidence of severe post-operative delirium showed a better trend (p = 0.093) in patients assigned to RemoweLL 2 (16.0%) versus Inspire (26.0%). Differences in enolase levels (p = 0.049), white blood cells (p = 0.006), and neutrophils (p = 0.003) in favor of RemoweLL 2 were also found. The use of novel and better construction technologies in CPB oxygenator devices results in measurable better neurocognitive and neurological outcomes in the elderly population undergoing CPB.

Mechanism of the Mongolian medicine Eerdun Wurile basic formula in improving postoperative cognitive dysfunction by inhibiting apoptosis through the SIRT1/p53 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The Mongolian medicine Eerdun Wurile is a commonly used Mongolian in folk medicine used to treat cerebral nervous system diseases such as cerebral hemorrhage, cerebral thrombosis, nerve injury and cognitive function, cardiovascular diseases such as hypertension and coronary heart disease. Eerdun wurile may effect anti-postoperative cognitive function.

AIM OF THE STUDY

To investigate the molecular mechanism of the Mongolian medicine Eerdun Wurile Basic Formula (EWB) in improving postoperative cognitive dysfunction (POCD) based on Network pharmacology, and to confirm involvement of the SIRT1/p53 signal pathway, one of the key signal pathways, by using the POCD mouse model.

MATERIAL AND METHODS

Obtain compounds and disease-related targets through TCMSP, TCMID, PubChem, PharmMapper platforms, GeneCards, and OMIM databases, and screen intersection genes; Use Cytoscape software to build a "drug-ingredient-disease-target" network, and the STRING platform for protein interaction analysis.; R software was used to analyze the function of gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment.; AutoDock Vina software for active components and core targets to Perform molecular docking. The POCD mouse model was prepared by intracerebroventricular injection of lipopolysaccharide (LPS), and the morphological changes of hippocampal tissue were observed by hematoxylin-eosin (HE) staining, Western blot, immunofluorescence and TUNEL were used to verify the results of network pharmacological enrichment analysis.

RESULTS

There were 110 potential targets for improving POCD by EWB, 117 items were enriched by GO, and 113 pathways were enriched by KEGG, among which the SIRT1/p53 signaling pathway was related to the occurrence of POCD. Quercetin, kaempferol, vestitol, β-sitosterol and 7-methoxy-2-methyl isoflavone in EWB can form stable conformations with low binding energy with core target proteins IL-6, CASP3, VEGFA, EGFR and ESR1. Animal experiments showed that compared with the POCD model group, the EWB group could significantly improve the apoptosis in the hippocampus of the mice, and significantly down-regulate the expression of Acetyl-p53 protein (P < 0.05).

CONCLUSION

EWB can improve POCD with the characteristics of multi-component, multi-target, and multi-pathway synergistic effects. Studies have confirmed that EWB can improve the occurrence of POCD by regulating the expression of genes related to the SIRT1/p53 signal pathway, which provides a new target and basis for the treatment of POCD.

Utility of cerebral oximetry in balloon mitral valvotomy and its correlation with post-procedure neurological complications: A pragmatic prospective observational study

Background and Aims

Neurological complications (NCs) are significantly associated with reduced regional cerebral saturation (rSO₂) in patients undergoing cardiac surgeries, as assessed with cerebral oximetry (COx). However, limited evidence is available in patients undergoing balloon mitral valvotomy (BMV). Thus, we evaluated the utility of COx in patients undergoing BMV, the incidence of BMV-related NCs and the association of >20% reduction in rSO₂ with NCs.

Methods

This pragmatic, prospective, observational study was performed after ethical approval, over November 2018 to August 2020, in the cardiology catherization laboratory of a tertiary care hospital. The study involved 100 adult patients undergoing BMV for symptomatic mitral stenosis. The patients were evaluated at initial presentation, pre-BMV, post-BMV and 3 months after the BMV.

Results

The incidence of NCs was 7%, including transient ischaemic attack (n = 3), slurred speech (n = 2) and hemiparesis (n = 2). A significantly greater proportion of patients with NCs had a > 20% decrease in the rSO₂ (P value = 0.020). At >20% cut-off, the COx had a sensitivity and specificity of 57.1% and 80%, respectively, in the prediction of NCs. Female sex (P value = 0.039), history of cerebrovascular episodes (P value < 0.001) and number of balloon attempts (P value < 0.001) were significantly associated with NCs. Patients with and without NCs had a significantly greater post-BMV mean % change in rSO₂ than pre-BMV (both right and left sides), but the magnitude of mean % change was greater in those with NCs.

Conclusions

COx alone has low sensitivity and specificity in the prediction of NCs and cannot reliably predict the development of post-BMV NCs.

The impact of postoperative cognitive training on health-related quality of life and cognitive failures in daily living after heart valve surgery: A randomized clinical trial

BACKGROUND

Heart surgery is a risk factor for objectively and subjectively assessable postoperative cognitive decline (POCD), which is relevant for everyday life. The aim of this study was to investigate whether early postoperative cognitive training has an impact on health-related quality of life and cognitive failures in daily living after cardiac surgery.

METHODS

The study was a two-arm, randomized, controlled, outcome-blinded trial involving older patients undergoing elective heart valve surgery with extracorporeal circulation (ECC). Recruitment took place at the Departments of Cardiac Surgery of the Kerckhoff Clinic in Bad Nauheim (Germany) and the University Hospital in Giessen (Germany). The patients were randomized (1:1 ratio) to either a paper-and-pencil-based cognitive training group or a control group. We applied the Short Form Health Survey (SF-36) and the Cognitive Failures Questionnaire (CFQ) prior to surgery and 3 months after the cognitive training. Data were analyzed in a per-protocol fashion.

RESULTS

Three months after discharge from rehabilitation, the training group (n = 31) showed improvement in health-related quality of life compared to the control group (n = 29), especially in role limitations due to emotional problems (U = -2.649, p = .008, η²  = 0.121), energy and fatigue (F[2.55] = 5.72, p = .020, η²  = 0.062), social functioning (U = -2.137, p = .033, η²  = 0.076), the average of all SF-36 factors (U = -2.374, p = .018, η²  = 0.094), health change from the past year to the present time (U = -2.378, p = .017, η²  = 0.094), and the mental component summary (U = -2.470, p = .013, η²  = 0.102).

CONCLUSION

As our cognitive training has shown beneficial effects, this intervention could be a promising method to enhance health-related quality of life after cardiac surgery.

Volatile Anaesthesia versus Total Intravenous Anaesthesia for Cardiac Surgery—A Narrative Review

Recent research has contested the previously accepted paradigm that volatile anaesthetics improve outcomes in cardiac surgery patients when compared to intravenous anaesthesia. In this review we summarise the mechanisms of myocardial ischaemia/reperfusion injury and cardioprotection in cardiac surgery. In addition, we make a comprehensive analysis of evidence comparing outcomes in patients undergoing cardiac surgery under volatile or intravenous anaesthesia, in terms of mortality and morbidity (cardiac, neurological, renal, pulmonary).