Is postoperative cognitive decline after cardiac surgery associated with plasma beta amyloid 1–42 levels?

Background Postoperative cognitive decline following cardiac surgery is one of the frequently reported complications affecting postoperative outcome, characterized by impairment of memory or concentration. The aetiology is considered multifactorial and the research conducted so far has presented contradictory results. The proposed mechanisms to explain the cognitive decline associated with cardiac surgery include the neurotoxic accumulation of β-amyloid (Aβ) proteins similar to Alzheimer's disease. The comparison of coronary artery bypass grafting procedures concerning postoperative cognitive decline and plasmatic Aβ1-42 concentrations has not yet been conducted. Methods The research was designed as a controlled clinical study of patients with coronary artery disease undergoing surgical myocardial revascularization with or without the use of a cardiopulmonary bypass machine. All patients completed a battery of neuropsychological tests and plasmatic Aβ1-42 concentrations were collected. Results The neuropsychological test results postoperatively were significantly worse in the cardiopulmonary bypass group and the patients had larger shifts in the Aβ1-42 preoperative and postoperative values than the group in which off-pump coronary artery bypass was performed. Conclusions The conducted research confirmed the earlier suspected association of plasmatic Aβ1-42 concentration to postoperative cognitive decline and the results further showed that there were less changes and lower concentrations in the off-pump coronary artery bypass group, which correlated to less neurocognitive decline. There is a lot of clinical contribution acquired by this research, not only in everyday decision making and using amyloid proteins as biomarkers, but also in the development and application of non-pharmacological and pharmacological neuroprotective strategies.

The Neutrophil to Lymphocyte Ratio and Serum Albumin as Predictors of Acute Kidney Injury After Coronary Artery Bypass Grafting

Postoperative acute kidney injury (AKI) is a highly prevalent and serious complication after cardiac surgery. The aim of this study is to identify the predictors of AKI and the cut-off values after isolated off-pump coronary artery bypass grafting (OPCAB). A total of 329 adult patients, who underwent isolated OPCAB between December 2008 and February 2021, were retrospectively analyzed. The patients were divided into three groups: non-AKI, early AKI and late AKI groups. The early AKI group or the late AKI group were defined as ‘having AKI that occurred before or after 48 hours postoperatively’, respectively. Multivariate logistic regression analysis was performed to identify the predictors of AKI. Receiver operating characteristic (ROC) curve analysis was used to evaluate the cutoff value, the sensitivity, and the specificity of the predictors. On the multivariate analysis, the emergency surgery, the preoperative serum albumin, and the postoperative day 1 neutrophil to lymphocyte ratio (NL ratio) were identified as the independent predictors of AKI. However, neither albumin nor the NL ratio predicted late AKI. The present study showed the preoperative albumin and the postoperative day 1 NL ratio were the robust and independent predictors of postoperative early AKI in isolated OPCAB.

Microcirculatory Response to Blood vs. Crystalloid Cardioplegia During Coronary Artery Bypass Grafting With Cardiopulmonary Bypass

Background: Blood cardioplegia attenuates cardiopulmonary bypass (CPB)-induced systemic inflammatory response in patients undergoing cardiac surgery, which may favorably influence the microvascular system in this cohort. The aim of this study was to investigate whether blood cardioplegia would offer advantages over crystalloid cardioplegia in the preservation of microcirculation in patients undergoing coronary artery bypass grafting (CABG) with CPB.Methods: In this prospective observational cohort study, 20 patients who received crystalloid (n = 10) or blood cardioplegia (n = 10) were analyzed. The microcirculatory measurements were obtained sublingually using incident dark-field imaging at five time points ranging from the induction of anesthesia (T0) to discontinuation of CPB (T5).Results: In the both crystalloid [crystalloid cardioplegia group (CCG)] and blood cardioplegia [blood cardioplegia group (BCG)] groups, perfused vessel density (PVD), total vessel density (TVD), and proportion of perfused vessels (PPV) were reduced after the beginning of CPB. The observed reduction in microcirculatory parameters during CPB was only restored in patients who received blood cardioplegia and increased to baseline levels as demonstrated by the percentage changes from T0 to T5 (%Δ)T0−T5 in all the functional microcirculatory parameters [%ΔTVDT0−T5(CCG): −10.86 ± 2.323 vs. %ΔTVDT0−T5(BCG): 0.0804 ± 1.107, p < 0.001; %ΔPVDT0−T5(CCG): −12.91 ± 2.884 vs. %ΔPVDT0−T5(BCG): 1.528 ± 1.144, p < 0.001; %ΔPPVT0−T5(CCG): −2.345 ± 1.049 vs. %ΔPPVT0−T5(BCG): 1.482 ± 0.576, p < 0.01].Conclusion: Blood cardioplegia ameliorates CPB-induced microcirculatory alterations better than crystalloid cardioplegia in patients undergoing CABG, which may reflect attenuation of the systemic inflammatory response. Future investigations are needed to identify the underlying mechanisms of the beneficial effects of blood cardioplegia on microcirculation.

The Effect of Paracetamol on the Patient-Controlled Pain After Coronary Artery Bypass Surgery: A Randomized Clinical Trial Study

Background: Pain is one of the patients' common problems, and usual morbidity after coronary artery bypass graft (CABG). This study aimed to assess the effect of Paracetamol and fentanyl in reducing post-CABG pain. Methods: This double-blind randomized clinical trial was conducted on 160 patients undergoing elective CABG (80 in group F (Fentanyl) and 80 in group P (Paracetamol)), at the cardiac surgery department of hospitals affiliated with Zahedan University of Medical Sciences. In group F, 50μg of Fentanyl (intravenous (IV)) was injected followed by a solution of 10 μg/cc at a rate of 4 cc/hr. For patients in group P, 15 mg/kg of Paracetamol (IV) was administered followed by a solution of 25 μg/cc at a rate of 4 cc/hr. Patients have been infused with the named drugs within the first 24 hours after the operation. Pain severity was assessed by the visual pain score (VAS) tool at baseline, and two, four, eight, twelve, and twenty-four hours after the surgery. Results: The mean of pain score in 12 (P-value=0.002) and 24 (P-value<0.0001) hours after surgery in group P was significantly less than that of group F. The mean heart rate in patients receiving Paracetamol was significantly (P-value = 0.005) less than that of patients receiving Fentanyl for 4 hours after surgery. The mean of increasing creatinine postoperatively in two groups was significant. The mean of increasing AST and ALT postoperatively in group P was significant with no case of liver function impairment. Conclusion: It seems Paracetamol is a good choice for reducing post-CABG pain with no significant complication, although further and more comprehensive research is needed.

Glycemic Control in Coronary Artery Bypass Graft Surgery: A Different Perspective

Background: Hyperglycemia during coronary artery bypass graft surgery (CABG) strongly predicts intra- and post-operative adverse consequences. Objectives: This study aimed to evaluate the quality of glycemic management during CABG in an academic center regarding peripheral blood and coronary sinus values. Methods: This prospective descriptive study encompassed 55 eligible patients undergoing on-pump CABG surgery in 2020. Peripheral blood glucose (BG) was measured four times, before anesthesia induction (T0), before cardiopulmonary bypass pump (CPB) (T1), during CPB (T2), at the end of CPB (T3), and at the end of surgery (T4). The surgeon also took a sample of the coronary sinus BG. Results: The BG variations from T0 to T4 were statistically significant (P < 0.0001). The higher values detected in the ASA class III compared to ASA classes II were statistically significant at T1 (P = 0.01) and T2 (P = 0.025): patients with the higher BMI showed the higher levels of BG. In this regard, the differences were significant at T0 (P = 0.0001), T2 (P = 0.004), and T3 (P = 0.015). Regarding coronary sinus, the mean BG was 222.18 ± 75.74 mg/dL. It was also observed that the ASA class III (P = 0.001), longer duration of CPB (P = 0.021), higher IV fluid volume administrated during surgery (P = 0.023), higher BMI (P = 0.0001), and less urine volume at the end of surgery (P = 0.049) were significantly associated with the higher BG of the coronary sinus. Conclusions: The existing glycemic management protocols on the CABG patients were acceptable in our hospital. However, the BG level of the coronary sinus was higher than the peripheral one.