Chronic Kidney Disease and Cognitive Dysfunction after Cardiac Surgery

Postoperative cognitive dysfunction in clinical practice

Ischemic heart disease is a significant cause of mortality and morbidity in Western populations. Consistent with this, coronary artery bypass graft (CABG) surgery remains one of the most frequently performed major surgeries. Improved survival rates mean that our research focus now extends beyond surgical technique to include quality of postoperative outcome. Postoperative cognitive dysfunction (POCD) has emerged as one of the most challenging and hotly debated issues, with increasing impetus to answer the unresolved question: does fixing the heart come at a cost to the brain? CABG surgery is associated with neurological events including stroke in 1.6%1 and delirium in 5.8%2 of patients. Beyond these severe and marked alterations to neurological function, there has been a widely held belief that CABG surgery is associated with POCD, which may presage a decline toward dementia. Research has been influenced by the 1995 Consensus Statement3 into the study of POCD in patients undergoing CABG surgery. Although the methods of investigation set forth by the Consensus Statement achieved widespread acknowledgment, its specific recommendations have not always been followed.4 Despite significant methodological issues, it seems that the balance of interpretation has historically been in favor of CABG surgery as a cause of significant POCD. More recently, however, a review of a series of publications from a well-controlled longitudinal cohort study conducted at Johns Hopkins5 and a meta-analysis6 suggested that cognition is in fact stable or may even show some improvement after CABG surgery in the majority of patients, at least within the first year (Figures 1 and 2). There is little doubt that POCD affects some patients in the short term, but the pathophysiological mechanisms underlying this and the influence on longer-term cognitive function remain uncertain. For research to progress, we require a paradigmatic shift in our focus from …

In this issue of Circulation , Djaiani and associates report that the processing of shed blood with a cell saver resulted in a significant reduction in postoperative neurocognitive dysfunction after coronary artery bypass surgery (CABG) in elderly patients.1 The authors further implied that this significant improvement in neurocognition was a result of less lipid embolization in those patients in whom a cell saver was used. The study was a randomized double-blinded trial that compared the use of a cell saver with cardiotomy suction (defined as control). Cardiotomy suction is a standard component of cardiopulmonary bypass (CPB), in which shed blood in the mediastinum is suctioned to a venous reservoir, where it is collected and then periodically reinfused through the arterial circuit to the patient. This technique was not used in patients in the cell saver group, but rather shed blood was suctioned via the cell saver system and processed, and red blood cells alone were infused to the patient through a similar arterial circuit. A standard 32-μm filter was used in the arterial pressure line in both groups. Article p 1888 Elderly patients who underwent CABG were chosen because it has been documented that these individuals are at increased risk to develop neurological dysfunction after cardiac surgery. The study was powered (n=209) to see a 50% reduction in cognitive dysfunction with additional patients added (for a total of 226 patients) to compensate for potential drop out, which turned out to be similar in both groups. The primary end point of neurocognitive evaluation was based on a battery of standardized and validated tests used to assess neuropsychological outcome. Evaluation was done at baseline and on follow-up at 6 weeks. In addition to neurocognitive decline, Figure 1 in Djaiani et al also demonstrates improvement in the battery of 12 tests documenting …

Central Nervous System Dysfunction after Noncardiac Surgery and Anesthesia in the Elderly

ObjectiveThis study aims to compare the effects of sevoflurane (SEV) and propofol (PRO) on postoperative cognitive dysfunction (POCD) in patients undergoing cardiac surgery (CS) under cardiopulmonary bypass (CPB), with a focus on evaluating the efficacy of these anesthetic agents in preventing POCD.MethodsA total of 113 patients undergoing CS with CPB were grouped into two: PRO group (n = 58) and SEV group (n = 55). Baseline data, anesthesia effects (CPB duration, anesthesia time, respiratory recovery time, and anesthesia recovery time), Montreal Cognitive Assessment (MoCA) scores, POCD incidence, neurological function markers (NSE, S-100β, MMP9), and serum inflammatory markers (IL-6, IL-8, TNF-α) were analyzed. The study was conducted between March 2018 and May 2021.ResultsThe PRO group showed significantly shorter anesthesia time (P < 0.05), respiratory recovery time (P < 0.05), and anesthesia recovery time (P < 0.05) compared to the SEV group. The postoperative MoCA score in the PRO group reduced markedly compared with the baseline, but still higher than that in the SEV group (P < 0.05). The incidence of POCD was significantly lower in the PRO group (5.17% vs. 27.27%, P = 0.001). The levels of NSE, S-100β, MMP9, IL-6, IL-8, and TNF-α were significantly elevated compared to baseline values, but still lower than those in the SEV group (P < 0.05 for all comparisons).ConclusionPRO is more effective than SEV in preventing POCD in patients undergoing CS with CPB. It provides superior anesthetic effects and offers better protection against neuronal damage and serum inflammation compared to SEV.Clinical trial numberNot applicable.

To investigate the incidence rate and the risk factors for postoperative cognitive dysfunction (POCD) in patients underwent coronary artery bypass grafting surgery. A total of 147 patients underwent elective coronary artery bypass grafting (CABG) surgery between January to July 2013 were included in this study. POCD was diagnosed using a neuropsychological test battery. All enrolled patients were interviewed on the day before surgery, the seventh day and 3 months after surgery, respectively, by the same researcher, and were divided into two groups based on the results: the POCD group and the non-POCD group. The information, including age, sex, body mass index, educational status, comorbidities, history of smoking and drinking, ASA grade, left ventricular ejection fraction, operation method, duration of operations, regional cerebral oxygen saturation, the lowest haemoglobin concentrations and the haemoglobin concentration decline rate during the operation, tracheal catheter retention time, postoperative pain on visual analogue scales (VAS) and systemic inflammatory response syndrome score (SIRS score), were recorded based on a schedule of survey. Multivariate logistic regression was used to analyze the risk factors for POCD. A total of 101 patients finished this study. On 7 days and 3 months after surgery, 38 and 21 cases showed POCD, with an incidence rate at 37.6% and 20.8%, respectively. Interestingly, there was no significant difference in incidence of POCD between CABG and OPCABG group on both 7 days and 3 months after surgery (P>0.05). The logistic stepwise regression analysis indicated that the risk factors for POCD included advanced age (OR=1.177, 95%CI 1.071-1.292, P=0.001), the haemoglobin concentration decline rate (OR=1.334, 95%CI 1.152-1.545, P<0.05) and SIRS score (OR=2.815, 95%CI 1.014-7.818, P=0.047). The incidence rate of POCD was 37.6% and 20.8% on 7 days and 3 months after surgery respectively. Advanced age, the haemoglobin concentration decline rate and SIRS score are independent risk factors for POCD in patients underwent coronary artery bypass grafting surgery.

This study aims to investigate the clinical application value of the central venous-arterial carbon dioxide partial pressure difference (Pv-aCO2) in postoperative cognitive dysfunction(POCD) in patients with acute aortic dissection. A retrospective analysis was conducted on the general data of 236 patients. Blood gas samples were collected from the arterial and venous lines at various time points during the surgery, including before and after the initiation of cardiopulmonary bypass (CPB), immediately after CPB initiation, before and after deep hypothermic circulatory arrest, 30min after rewarming, and 5min before weaning from CPB. The partial PV-aCO2 was calculated. Based on the average PV-aCO2 value, patients were divided into an observation group (PV-aCO2 > 6 mmHg, n = 112) and a control group (PV-aCO2 < 6 mmHg, n = 124). The perioperative data and Mini-Mental State Examination (MMSE) scores were compared between the two groups to assess the incidence and severity of POCD. Additionally, the expression levels of peripheral serum S100β in the two groups were compared 6h postoperatively. The incidence of POCD was higher in the observation group compared to the control group, while MMSE scores and serum S100β levels were lower in the observation group. Additionally, the observation group patients with POCD had lower MMSE scores and serum S100β levels compared to the control group patients. In addition, logistic regression analysis revealed that advanced age, serum S100β levels, female gender, CPB time, unilateral brain perfusion time, hyperlipidemia, diabetes, and smoking history were all independent risk factors for postoperative POCD (all P < 0.05). Pv-aCO2 can effectively reflect the intraoperative cerebral metabolic level in patients with acute aortic dissection and can serve as an intraoperative warning indicator for cognitive dysfunction. Its clinical recommendation for use is warranted.

Postoperative cognitive dysfunction (POCD) is a prevalent complication of the central nervous system in elderly patients following cardiac surgery. This review aims to provide an overview of the etiology, risk factors, diagnostic assessment, and rehabilitation strategies for cognitive dysfunction occurring after cardiac surgery. The pathogenesis of POCD after cardiac surgery includes cerebral microembolism, neuroinflammation, and cryptogenic strokes. Risk factors are associated with advanced age, diminished preoperative cognitive status, and anesthesia. Cognitive function screening tools used for pre- and postoperative assessments can detect changes in patients' cognitive levels in a timely manner. The timely provision of appropriate rehabilitation methods, including cognitive function training, exercise training, transcranial direct current stimulation, and perioperative acupuncture, is crucial, with emerging technologies such as virtual reality playing an increasingly significant role. In conclusion, POCD is a common postoperative complication in elderly cardiac surgery patients, with age and reduced preoperative cognitive function being the primary risk factors. A comprehensive rehabilitation strategy can more effectively address postoperative cognitive dysfunction in patients.

Coronary artery bypass surgery, performed with or without cardiopulmonary bypass, is frequently followed by postoperative cognitive decline. Near-infrared spectroscopy is commonly used to assess cerebral tissue oxygenation, especially during cardiac surgery. Recent studies have suggested an association between cerebral desaturation and postoperative cognitive dysfunction. We therefore studied cerebral oxygen desaturation, defined as area under the cerebral oxygenation curve < 40% of > 10 min.%, with respect to cognitive performance at 4 days (early) and 3 months (late) postoperatively, compared with baseline, using a computerised cognitive test battery. We included 60 patients, of mean (SD) age 62.8 (9.4) years, scheduled for elective coronary artery bypass grafting, who were randomly allocated to surgery with or without cardiopulmonary bypass. Cerebral desaturation occurred in only three patients and there was no difference in cerebral oxygenation between the two groups at any time. Among patients who received cardiopulmonary bypass, 18 (62%) had early cognitive decline, compared with 16 (53%) in the group without cardiopulmonary bypass (p = 0.50). Three months after surgery, 11 patients (39%) in the cardiopulmonary bypass group displayed cognitive dysfunction, compared with four (14%) in the non-cardiopulmonary bypass group (p = 0.03). The use of cardiopulmonary bypass was identified as an independent risk factor for the development of late cognitive dysfunction (OR 6.4 (95% CI 1.2-33.0) p = 0.027. In conclusion, although cerebral oxygen desaturation was rare in our population, postoperative cognitive decline was common in both groups, suggesting that factors other than hypoxic neuronal injury are responsible.

Central nervous system complications continue to be major causes of morbidity and mortality after cardiac surgery. The purpose of this study was to identify the risk factors for postoperative cognitive dysfunction after coronary artery bypass graft (CABG) surgery. Eighty-eight patients scheduled for elective CABG were studied. After the induction of anesthesia, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb for the continuous monitoring of jugular venous oxygen hemoglobin saturation (SjvO(2)). The hemodynamic parameters and arterial and jugular venous blood gases were measured during cardiopulmonary bypass (CPB). All patients underwent a battery of neurological and neuropsychological tests one day before the operation and at 6 months after the operation. The incidence of a cognitive decline at 6 months was 24/88 (27.3%). Greater age (P = 0.04), the presence of renal failure (P < 0.001), and diabetes mellitus (P < 0.001) were more frequent in the patients with postoperative cognitive dysfunction at 6 months after the operation than in patients without cognitive dysfunction. Age (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0-1.7; P = 0.04), diabetes mellitus (OR, 1.8; 95% CI, 1.2-2.4; P < 0.01), and presence of renal failure (OR, 2.8; 95% CI, 2.4-4.3; P < 0.01) were associated with cognitive impairment at 6 months postoperatively. However, there was no relationship between the presence of atherosclerosis in the ascending aorta and postoperative cognitive dysfunction after CABG surgery. A greater age, diabetes mellitus, and renal failure were found to be risk factors for development of cognitive impairment at 6 months after CABG with CPB.

Background and Aims:Advancing age is associated with poor physiological reserve to combat stressors of surgery and anaesthesia, which is termed frailty, and it leads to postoperative complications. Frailty has been found to have a strong association with postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) in cardiac surgeries. This study aims to determine the association of frailty with POD and POCD in patients undergoing non-cardiac surgeries.Methods:A prospective observational, cohort study was done at a tertiary-level hospital on 130 patients aged 55 years and above undergoing surgery under general anaesthesia. Preoperative frailty was classified using a 5-factor modified frailty index (5mFI) and sarcopenia [hand grip strength (HGS)]. POD and POCD were assessed with the revised Delirium Rating Scale (DRS) and Addenbrooke’s Cognitive Examination-III at 24 h, 72 h and 30 days after surgery. Association between 5mFI and HGS with postoperative POD and POCD were calculated using linear regression model.Results:Of 117 patients analysed, 58% were identified as frail (5mFI score ≥0.2), exhibiting 2.9 times higher risk of POD [odds ratio (OR) 2.933, 95% confidence interval (CI): 1.001, 8.600, P = 0.050] and 5.8 times higher risk of POCD (OR: 5.380, 95% CI: 1.718, 16.685, P = 0.004) compared to non-frail counterparts. The correlation between 5mFI and postoperative revised DRS-98 scores was statistically significant (P < 0.001), indicating a moderate positive association. However, sarcopenic patients displayed higher but statistically insignificant incidence rates of POD (OR: 1.967, 95% CI: 0.771, 5.014, P = 0.157) and POCD (OR: 1.070, 95% CI: 0.442, 2.589, P = 0.880) than non-sarcopenic patients. Patients with 5mFI scores >0.4 showed a notably increased risk of adverse events within 30 days post-surgery.Conclusions:Our study proves the hypothesis that frailty, apart from age, contributes to POD and POCD. Using 5mFI as a predictor in pre-anaesthetic checkups can help identify vulnerable patients early and implement necessary interventions to decrease the burden of cognitive decline.

Study objectiveThis meta-analysis aimed to assess whether continuous intravenous administration of DEX during surgery can be part of the measures to prevent the onset of postoperative delirium and postoperative cognitive dysfunction in elderly individuals following regional anesthesia.MethodsWe searched the databases of PubMed, Embase, the Cochrane Library and China National Knowledge Infrastructure (by June 1, 2023) for all available randomized controlled trials assessing whether intravenous application of dexmedetomidine can help with postoperative delirium and postoperative cognitive dysfunction in the elderly with regional anesthesia. Subsequently, we carried out statistical analysis and graphing using Review Manager software (RevMan version 5.4.1) and STATA software (Version 12.0).Main resultsWithin the scope of this meta-analysis, a total of 18 randomized controlled trials were included. Among them, 10 trials aimed to assess the incidence of postoperative delirium as the primary outcome, while the primary focus of the other 8 trials was on the incidence of postoperative cognitive dysfunction. The collective evidence from these 10 studies consistently supports a positive relationship between the intravenous administration of dexmedetomidine and a decreased risk of postoperative delirium (RR: 0.48; 95%CI: 0.37 to 0.63, p < 0.00001, I2 = 0%). The 8 literature articles and experiments evaluating postoperative cognitive dysfunction showed that continuous intravenous infusion of dexmedetomidine during the entire surgical procedure exhibited a positive preventive effect on cognitive dysfunction among the elderly population with no obvious heterogeneity (RR: 0.35; 95%CI: 0.25 to 0.49,p < 0.00001, I2 = 0%).ConclusionAdministering dexmedetomidine intravenously during surgery can potentially play a significant role in preventing postoperative delirium and postoperative cognitive dysfunction in patients older than 60 years with regional anesthesia according to this meta-analysis.

Objective To evaluate the effect of dexmedetomidine (DEX) on inflammatory responses in patients performed cardiac surgery with cardiopulmonary bypass (CPB) at perioperative period, and explore the influencing factors of postoperative cognitive dysfunction (POCD) in these patients. Methods Eighty patients scheduled for cardiac surgery with CPB at hospital from July 2013 to June 2014 were randomized into control group and DEX group (n=40). Before induction of anesthesia, DEX was administered to the patients from DEX group with a loading dose of 1 μg/kg followed by maintenance dose of 0.5 μg/(kg·h), while the same dose of normal saline was administered to patients from control group. Before incision (T0), 30 min after beginning of CBP (T1), 30 min after end of CBP (T2), end of surgery (T3), 24 h after end of surgery (T4) and 72 h after end of surgery (T5), venous blood samples from jugular bulb catheters were drawn, and serum concentrations of tumor necrosis factor α (TNF-α), interleukin (IL)-6 and IL-10 were determined. One d before operation, 3rd, 7th, 90th and 180th day after operation, the cognitive functions of patients were tested with mini-mental state examination (MMSE), digit span subtest (DSpan), digit symbol subtest (DSy) and trail making test (TMT). The DSpan contained digit span forward subtest (DSpan-F) and digit span reverse subtest (DSpan-R). Results The serum concentrations of TNF-α, IL-6 and IL-10 in two groups at T1, T2 and T3 were significantly higher than those at T0 (P<0.05); the serum concentrations of TNF-α and IL-6 in DEX group were significantly lower than those in control group (P<0.05), while that of IL-10 in DEX group was significantly higher than that in control group (P<0.05). In the control group, all results excepted for TMT on the 3rd d after operation, MMSE and DSpan-R results on the 7th d after operation, and DSpan-R results on the 90th d after operation were significantly lower than those results one d before operation (P<0.05); in the DEX group, MMSE and DSpan-R results on the 3rd d after operation were significantly lower than those results one d before operation (P<0.05); MMSE and DSpan-R results on the 3rd and 7th d after operation, and DSpan-R results on the 90th d after operation in the DEX group were significantly higher than those in the control group (P<0.05); TMT on the 3rd d after operation in the DEX group was significantly lower than that in the control group (P<0.05). The incidence rate of POCD in the DEX group on the 3rd and 7th d after operation (23.5% and 14.7%) was significantly lower than that in the control group (46.9% and 37.5%, P<0.05). Conclusion DEX with a loading dose of 1 μg/kg followed by maintenance dose of 0.5 μg/(kg·h) can reduce the early incidence of POCD in cardiac surgery with cardiopulmonary bypass, but can not reduce the late incidence. Key words: Dexmedetomidine; Cardiopulmonary bypass; Cardiac surgery; Neuroinflammation; Postoperative cognitive dysfunction

To determine the relevance of surgery and other causative factors to the incidence of postoperative cognitive dysfunction (POCD) in patients with severe systemic disease. This observational study included 107 noncardiac surgical patients and 26 nonsurgical control subjects, all of whom had an American Society of Anesthesiologists physical classification status of 3. Cognitive assessment was performed preoperatively and 7 days postoperatively, or with a 7-day interval for the control group. POCD was calculated as a combined Z-score. Mini Mental State Examination (MMSE) was used to exclude patients with pre-existing cognitive deficit (MMSE score ≤ 23). Surgical and other factors including duration of surgery/anaesthesia and length of stay in the intensive care unit (ICU) were recorded. After 7 days, POCD was found in 40/107 (37.4%) surgical patients compared with 4/26 (15.4%) nonsurgical controls. Preoperative MMSE score, duration of surgery/anaesthesia, and length of stay in the ICU and hospital were associated with POCD. Logistic regression analysis revealed that preoperative MMSE score was an independent predictor of POCD. Lower baseline MMSE score was the only independent predictor for POCD in patients with severe systemic disease.

HighlightsThe effectiveness of cognitive rehabilitation in reducing the incidence of early postoperative cognitive dysfunction in patients who have undergone coronary artery bypass grafting has been demonstrated for the first time by optimizing neurodynamics and memory parameters. AbstractAim. To study the effectiveness of cognitive training (CT) using a combination of simple visual-motor reactions with a set of arithmetic and verbal tasks to reduce the frequency of early postoperative cognitive dysfunction (POCD) in patients who underwent coronary artery bypass grafting (CABG), and to evaluate the dynamics of the neurovascular unit markers (NVU).Methods. The prospective randomized study included 81 patients: group with CT (n = 43) and the comparison group without CT (n = 38). All patients underwent general clinical, laboratory and instrumental examinations as well as extended neuropsychological examination and determination of concentrations in the plasma of peripheral blood of NVU markers.Results. Patients who underwent CT with a combination of vision-motor task and cognitive components in the early post-operative period of CABG showed better psychomotor and executive functions (faster reaction time, a smaller number of errors and missed signals), as well as attention (more processed symbols in the 4th minute of Burdon’s test) compared to patients without training. The patients with CT also had a decrease in the concentration of S100β protein in peripheral blood at 11–12 days after CABG and a tendency towards higher the concentration of BDNF. The comparison group had an increase in the concentration of S100β protein at 1st day after surgery and maintained an elevated level until 11–12 days after CABG.Conclusion. Thus, the cognitive rehabilitation as the combinations of simple visual-motor reactions with a set of arithmetic and verbal tasks in the early postoperative period of CABG contributed to a decrease in the incidence of early POCD and the maintenance of the cognitive status of patients to a greater extent due to the optimization of the activity of the neurodynamic and short-term memory domains. The decrease in the concentration of S100β protein in the peripheral blood at 11–12 days after CABG and the tendency towards higher concentration of BDNF, observed in patients with CT in comparison to patients without CT, may indicate NVU reorganization.