ACUTE KIDNEY INJURY AFTER OPEN-HEART SURGERY PROCEDURES

Perioperative Evaluation of Arterial and Venous Whole Blood in the Lamb (Ovis aries) Fontan Model

Whole blood analysis can evaluate numerous parameters, including pH, pCO₂, pO₂, HCO₃ - , base excess, glucose, electrolytes, lactate, blood urea nitrogen, creatinine, bilirubin, and hemoglobin. This valuable tool enables clinicians to make more informed decisions about patient care. However, the current body of literature describing perioperative whole blood analysis in Dorset sheep (Ovis aries) is small, so clinicians lack adequate information to guide their decision-making when evaluating test results. We evaluated arterial and venous whole blood pH, bicarbonate, pCO₂, lactate, creatinine, and blood urea nitrogen before and for the first 24 hours after surgery in 2 cohorts of male and female Ovis arie s undergoing one of 2 major cardiovascular procedures, a Single-Stage Fontan or an inferior vena cava to pulmonary artery extracardiac conduit implantation (IP-ECC). The cohort undergoing a Single-Stage Fontan, which is the more complex procedure, exhibited greater deviation from baseline measurements than did the cohort undergoing the IP-ECC for lactate, bicarbonate, and creatinine. The cohort undergoing the IP-ECC showed no significant deviation from baseline for any parameters, potentially indicating a better safety margin than expected when compared with the Single-Stage Fontan. Together, these results indicate the clinical value of arterial and venous whole blood measurements in perioperative management of sheep and can provide a reference for clinicians managing sheep after significant cardiovascular procedures.

Acute kidney injury interacts with VKORC1 genotype on initiative warfarin dose among heart surgery recipients: a real-world research

Patients who receive heart valve surgery need anticoagulation prophylaxis to reduce the risk of thrombosis. Warfarin often is a choice but its dosage varies due to gene and clinical factors. We aim to study, among them, if there is an interaction between acute kidney injury and two gene polymorphisms from this study. We extracted data of heart valve surgery recipients from the electronic health record (EHR) system of a medical center. The primary outcome is about the average daily dose of warfarin, measured as an additive interaction effect (INTadd) between acute kidney injury (AKI) and warfarin-related gene polymorphisms. The confounders, including age, sex, body surface area (BSA), comorbidities (i.e., atrial fibrillation [AF], hypertension [HTN], congestive heart failure [CHF]), serum albumin level, warfarin-relevant gene polymorphism (i.e., CYP2C9, VKORC1), prosthetic valve type (i.e., metal, bio), and warfarin history were controlled via a multivariate-linear regression model. The study included 200 patients, among whom 108 (54.00%) are female. Further, the mean age is 54.45 years, 31 (15.50%) have CHF, and 40 (20.00%) patients were prescribed concomitant amiodarone, which potentially overlays with the warfarin prophylaxis period. During the follow-up, AKI occurred in 30 (15.00%) patients. VKORC1 mutation (1639G>A) occurred in 25 (12.50%) patients and CYPC29 *2 or *3 mutations presented in 20 patients (10.00%). We found a significant additive interaction effect between AKI and VKORC1 (- 1.17, 95% CI - 1.82 to - 0.53, p = 0.0004). This result suggests it is probable that there is an interaction between acute kidney injury and the VKORC1 polymorphism for the warfarin dose during the initial period of anticoagulation prophylaxis.

Cardiac damage following renal ischemia reperfusion injury increased with excessive consumption of high fat diet but enhanced the cardiac resistance to reperfusion stress in rat

Renal ischemia-reperfusion (IR) injury inflicts remote cardiac dysfunction. Studies on rats fed with a high-fat diet (HD) showed contradictory results: some demonstrated increased sensitivity of the heart and kidney to IR injury, while others reported resistance. In this study, we examined cardiac dysfunction and compromised cardiac tolerance associated with renal IR in HD and standard diet (SD) fed rats. Male Wistar rats fed with HD or SD diet for 16 weeks were subjected to either renal sham or IR protocol (bilateral clamping for 45 min and reperfusion for 24 h). The hearts isolated from these rats were further subjected to normal perfusion or IR procedure to study cardiac response. Renal IR surgery negatively affected cardiac function with substantial changes in the cardiac tissues, like mitochondrial dysfunction, elevated oxidative stress, and inflammation. HD-fed rat hearts exhibited hypertrophy at the end of 16 weeks, and the consequential impact on the heart was higher in the animals underwent renal IR surgery than with sham surgery. However, the IR induction in the isolated heart from renal sham or renal IR operation showed significant tissue injury resistance and better physiological recovery in HD-fed rats. However, in SD-fed rats, only hearts from renal IR-operated rats showed resistance to cardiac IR, whereas hearts from renal sham-operated rats were more susceptible to IR damage. The augmented IR resistance in the heart with prior renal surgery was due to preserved mitochondrial bioenergetics function, reduced oxidative stress, and activation of the PI3K/AKT signaling axis.

Molecular hydrogen: prospective treatment strategy of kidney damage after cardiac surgery

Cardiac surgery-associated acute kidney injury is a common post-operative complication, mostly due to increasing oxidative stress. Recently, molecular hydrogen (H2 gas) has also been applied to cardiac surgery due to its ability to reduce oxidative stress. We evaluated the potential effect of H2 application on the kidney in an in vivo model of simulated heart transplantation. Pigs underwent cardiac surgery within 3 h while connected to extracorporeal circulation (ECC) and subsequent 60 min of spontaneous reperfusion of the heart. We used two experimental groups: T-pigs after transplantation and TH-pigs after transplantation treated with 4% H2 mixed with air during inhalation of anesthesia and throughout oxygenation of blood in ECC. The levels of creatinine, urea and phosphorus were measured in plasma. Renal tissue samples were analyzed by Western blot method for protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2), Kelch-like ECH-associated protein 1 (Keap-1), and superoxide dismutase (SOD1). After cardiac surgery, selected plasma biomarkers were elevated. However, H2 therapy was followed by the normalization of all these parameters. Our results suggest activation of Nrf2/Keap1 pathway as well as increased SOD1 protein expression in the group treated with H2. The administration of H2 had a protective effect on the kidneys of pigs after cardiac surgery, especially in terms of normalization of plasma biomarkers to control levels.

Efficacy of N-acetylcysteine in Preventing Acute Kidney Injury and Major Adverse Cardiac Events After Cardiac Surgery: A Meta-Analysis and Trial Sequential Analysis

Background

The effect of N-acetylcysteine (NAC), an antioxidant, on preventing acute kidney injury (AKI) and major adverse cardiac events (MACE) remains controversial. Therefore, we conducted this meta-analysis and trial sequential analysis to evaluate its efficacy on cardiac surgery-related adverse events.

Methods

PubMed, Embase, and Cochrane Library were searched for relevant studies from inception to June 2021. We selected randomized controlled trials comparing NAC with controls in patients undergoing cardiac surgery.

Results

Twenty-five studies including 2,444 patients met the inclusion criteria. The pooled results showed that there was no significant difference in the incidence of AKI between the NAC and control groups [relative risk (RR) = 0.91, 95% confidence interval (CI) = 0.77, 1.08, P = 0.28], but the trial sequential analysis (TSA) could not confirm this result. No difference was observed in the need for renal replacement therapy (RRT), all-cause mortality, MACE, length of stay in the intensive care unit (ICU), and length of stay in the hospital. Results of subgroup analysis results showed that intravenous infusion instead of oral NAC could significantly reduce the incidence of AKI and arrhythmia (RR = 0.84, 95% CI = 0.71, 0.99, P = 0.03, I² = 3% and RR = 0.74, 95% CI = 0.61, 0.91, P = 0.004, I² = 48%, respectively).

Conclusion

Intravenous administration of NAC can reduce the incidence of AKI and arrhythmia in patients after cardiac surgery, but cannot reduce all-cause mortality, AMI, cardiac insufficiency, and the number of patients using RRT. Oral NAC has no significant effect on the outcomes of patients after cardiac surgery.

Association Between the Presence of Pulmonary Hypertension Before Cardiovascular Surgery and the Nephroprotective Effect of Carperitide: A Retrospective Cohort Study

Introduction

We hypothesized that the nephroprotective and diuretic effects of carperitide are effective in patients with pulmonary hypertension. We examined the presence of preoperative pulmonary hypertension and the effects of carperitide.

Methods

In this retrospective cohort study, we included patients aged 20 years or older who received carperitide during cardiovascular surgery and were admitted to the postoperative intensive care unit. We used hospital data from March 2019 to September 2021. The outcomes were the incidence of acute kidney injury, the number of patients using renal replacement therapy in the intensive care unit, urine volume in the first 24 hours after surgery, and the difference in serum creatinine concentrations between before and after surgery. After adjusting for confounding factors by multivariate analysis, we compared the difference in outcomes with and without preoperative pulmonary hypertension (systolic pulmonary artery pressure ≥36 mmHg).

Results

The study included 244 patients, with 72 (29.5%) in the pulmonary hypertension group and 172 (70.5%) in the control group. Acute kidney injury occurred in eight (11.1%) patients in the pulmonary hypertension group and in 18 (10.5%) patients in the control group, with no significant difference by logistic regression analysis (odds ratio 1.40, 95% confidence interval 0.54-3.62, p=0.49). Additionally, the use of renal replacement therapy, urine volume at 24 hours postoperatively, and the difference in serum creatinine concentrations were not different between the two groups.

Conclusions

Our results suggest that the effect of carperitide during cardiovascular surgery is not affected by the presence or absence of pulmonary hypertension.

Analysis of Risk Factors for Perioperative Acute Kidney Injury and Management Strategies

Acute kidney injury (AKI) is a serious clinical syndrome, and one of the common comorbidities in the perioperative period. AKI can lead to complications in surgical patients and is receiving increasing attention in clinical workup. In recent years, the analysis of perioperative risk factors has become more in-depth and detailed. In this review, the definition, diagnosis, and pathophysiological characteristics of perioperative AKI are reviewed, and the main risk factors for perioperative AKI are analyzed, including advanced age, gender, certain underlying diseases, impaired clinical status such as preoperative creatinine levels, and drugs that may impair renal function such as non-steroidal anti-inflammatory drugs (NASIDs), ACEI/ARB, and some antibiotics. Injectable contrast agents, some anesthetic drugs, specific surgical interventions, anemia, blood transfusions, hyperglycemia, and malnutrition are also highlighted. We also propose potential preventive and curative measures, including the inclusion of renal risk confirmation in the preoperative assessment, minimization of intraoperative renal toxin exposure, intraoperative management and hemodynamic optimization, remote ischemic preadaptation, glycemic control, and nutritional support. Among the management measures, we emphasize the need for careful perioperative clinical examination, timely detection and management of AKI complications, administration of dexmedetomidine for renal protection, and renal replacement therapy. We aim that this review can further increase clinicians' attention to perioperative AKI, early assessment and intervention to try to reduce the risk of AKI.