Acute Kidney Injury and Prognosis After Cardiopulmonary Bypass: A Meta-analysis of Cohort Studies

The Impact of Acute Kidney Injury on Chronic Kidney Disease After Cardiac Surgery: A Systematic Review and Meta-analysis

OBJECTIVES

To evaluate the impact of acute kidney injury on transition to chronic kidney disease (CKD) after cardiac surgery and to determine frequency of incident CKD in these patients.

DESIGN

A systematic review and meta-analysis of observational studies.

SETTING

Electronic databases Medline and Embase were systematically searched from 1974 to February 6, 2023.

PARTICIPANTS

Eligible studies were original observational studies on adult cardiac surgery patients, written in the English language, and with clear kidney disease definitions. Exclusion criteria were studies with previously transplanted populations, populations with preoperative kidney impairment, ventricular assist device procedures, endovascular procedures, a kidney follow-up period of <90 days, and studies not presenting necessary data for effect size calculations.

INTERVENTIONS

Patients developing postoperative acute kidney injury after cardiac surgery were compared with patients who did not develop acute kidney injury.

MEASUREMENTS AND MAIN RESULTS

The search identified 4,329 unique studies, 87 underwent full-text review, and 12 were included for analysis. Mean acute kidney injury occurrence across studies was 16% (minimum-maximum: 8-50), while mean occurrence of CKD was 24% (minimum-maximum: 3-35), with high variability depending on definitions and follow-up time. Acute kidney injury was associated with increased odds of CKD in all individual studies. The pooled odds ratio across studies was 5.67 (95% confidence interval, 3.34-9.64; p < 0.0001).

CONCLUSIONS

Acute kidney injury after cardiac surgery was associated with a more than 5-fold increased odds of developing CKD. New-onset CKD occurred in almost 1 in 4 patients in the years after surgery.

Postoperative Hypotension After Cardiac Surgery Is Associated With Acute Kidney Injury

OBJECTIVES

To describe the incidence of postoperative hypotension in patients undergoing cardiac surgery during the first 12 hours in the intensive care unit (ICU) and any relationship between hypotension and the development of acute kidney injury (AKI).

DESIGN

This was a retrospective, observational cohort study.

SETTING

The study took place in a single-center tertiary teaching hospital in London, UK.

PARTICIPANTS

Adult patients (n = 100) who underwent elective cardiac surgery requiring intraoperative cardiopulmonary bypass between May and November 2021 were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A hypotensive event was defined as mean arterial pressure <65 mmHg lasting at least 1 minute. Invasive blood pressure data was analyzed for the first 12 hours after surgery, and any association between postoperative hypotension and AKI was assessed. A total of 91% of patients experienced hypotension in the first 12 hours postprocedure. On average, patients experienced 9 hypotensive events, with events lasting an average of 5 minutes. A total of 16 patients (16%) developed at least stage 1 AKI. The average duration of hypotension was significantly higher in the AKI group (4.6 min [IQR 3.3, 8.0] v 8.1 min [IQR 5.2, 14.2], p = 0.029). Those suffering AKI had longer ICU and hospital stays.

CONCLUSIONS

This study demonstrated that hypotension in the first 12 hours following cardiac surgery is common and prolonged hypotensive events are associated with developing AKI. This emphasizes the importance of treating hypotension aggressively and highlights a target for further research and intervention.

Intraoperative Glucose and Kidney Injury After On-Pump Cardiac Surgery: A Retrospective Cohort Study

INTRODUCTION

Acute kidney injury (AKI) is a common complication after on-pump cardiac surgery, and previous studies have suggested that blood glucose is associated with postoperative AKI. However, limited evidence is available regarding intraoperative glycemic thresholds in cardiac surgery. The aim of this study was to explore the association between peak intraoperative blood glucose and postoperative AKI, and determine the cut-off values for intraoperative glucose concentration associated with an increased risk of AKI.

METHODS

The study was retrospective and single-centered. Adult patients in West China Hospital of Sichuan University who underwent on-pump cardiac surgery (n = 3375) were included. The primary outcome was the incidence of AKI. Multivariable logistic analysis using restricted cubic spline was performed to explore the association between intraoperative blood glucose and postoperative AKI.

RESULTS

The incidence of AKI in the study population was 18.0% (607 of 3375). Patients who developed AKI had a significantly higher peak intraoperative glucose during the surgery compared to those without AKI. After adjustment for confounders, the incidence of AKI increased with peak intraoperative blood glucose (adjusted odds ratio, 1.08, 95% confidence interval 1.03, 1.12). Furthermore, it was demonstrated that the possibility of AKI was relatively flat till 127.8 mg/dL (7.1 mmol/L) glucose levels which started to rapidly increase afterward.

CONCLUSIONS

Increased intraoperative blood glucose was associated with an increased risk of AKI. Among patients undergoing on-pump cardiac surgery, avoiding a high glucose peak (i.e., below 127.8 mg/dL [7.1 mmol/L]) may reduce the risk of postoperative AKI.

Cardiopulmonary Bypass Blood Flow Rates and Major Adverse Kidney Events in Cardiac Surgery: A Propensity Score-adjusted Before-After Study

OBJECTIVES

Cardiac surgery associated-acute kidney injury is a common and serious postoperative complication of cardiac surgery, which is associated with increased postoperative morbidity and mortality. This study aimed to explore the association between cardiopulmonary bypass (CPB) blood flow rate (BFR), and major adverse kidney events (MAKEs) at day 30.

DESIGN

Retrospective single-center before-after observational study. Patients were divided in 2 groups according to CPB flow rates: a first group with an institutional protocol targeting a CPB-BFR of >2.2 L/min/m² (low CPB-BFR group), and a second group with a modified institutional protocol targeting a CPB-BFR of >2.4 L/min/m² (high CPB-BFR group). The primary outcome was MAKE at 30 days, defined as the composite of death, renal replacement therapy or persistent renal dysfunction.

SETTING

The data were collected from clinical routines in university hospital.

PARTICIPANTS

Adult patients who underwent elective and urgent cardiac surgery without severe chronic renal failure, for whom CPB duration was ≥90 minutes.

INTERVENTIONS

We included 533 patients (low CPB-BFR group, n = 270; high CPB-BFR group, n = 263).

MEASUREMENTS AND MAIN RESULTS

A significant decrease in MAKE at 30 days was observed in the high CPB-BFR group (3% v 8%; odds ratio [OR], 0.779; 95% confidence interval [CI], 0.661-0.919; p < 0.001) mainly mediated by a lower 30-day mortality in the high CPB-BFR group (1% v 5%; OR, 0.697; 95% CI, 0.595-0.817; p = 0.001), as was renal replacement therapy (1% v 4%; OR, 0.739; 95% CI, 0.604-0.904; p = 0.016).

CONCLUSIONS

In patients undergoing cardiac surgery, increased CPB-BFR was associated with a decrease in MAKE at 30 days including mortality and renal replacement therapy.

Adverse renal effects associated with cardiopulmonary bypass

Cardiac surgery on cardiopulmonary bypass (CPB) is associated with postoperative renal dysfunction, one of the most common complications of this surgical cohort. Acute kidney injury (AKI) is associated with increased short-term morbidity and mortality and has been the focus of much research. There is increasing recognition of the role of AKI as the key pathophysiological state leading to the disease entities acute and chronic kidney disease (AKD and CKD). In this narrative review, we will consider the epidemiology of renal dysfunction after cardiac surgery on CPB and the clinical manifestations across the spectrum of disease. We will discuss the transition between different states of injury and dysfunction, and, importantly, the relevance to clinicians. The specific facets of kidney injury on extracorporeal circulation will be described and the current evidence evaluated for the use of perfusion-based techniques to reduce the incidence and mitigate the complications of renal dysfunction after cardiac surgery.

The Treatment of Coronary Artery Disease in Patients with Chronic Kidney Disease: Gaps, Challenges, and Solutions

Background

Chronic kidney disease (CKD) is associated with a high burden of coronary artery disease (CAD), which remains the leading cause of death in CKD patients. Despite the high cardiovascular risk, ACS patients with renal dysfunction are less commonly treated with guideline-based medical therapy and are less frequently referred for coronary revascularization.

Summary

The management of CAD is more challenging in patients with CKD than in the general population due to concerns regarding side effects and renal toxicity, as well as uncertainty regarding clinical benefit of guideline-based medical therapy and interventions. Patients with advanced CKD and especially those receiving dialysis have not traditionally been represented in randomized trials evaluating either medical or revascularization therapies. Thus, only scant data from small prospective studies or retrospective analyses are available. Recently published studies suggest that there are significant opportunities to substantially improve both cardiovascular and renal outcomes of patients with CAD and CKD, including new medications and interventions. Thus, the objective of this review is to summarize the current evidence regarding the management of CAD in CKD patients, in particular with respect to improvement of both cardiovascular and renal outcomes.

Key Messages

Adequate medical therapy and coronary interventions using evidence-based strategies can improve both cardiac and renal outcomes in patients with CAD and CKD.

Pro: Individualized Optimal Perfusion Pressure-Maximizing Patient Care During Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) has revolutionized cardiac surgery but poses challenges such as hemodynamic instability and adverse clinical outcomes. Achieving optimal perfusion during CPB ensures adequate oxygen delivery to vital organs. Although mean arterial pressure is a key determinant of perfusion pressure, clear guidelines for optimal perfusion have yet to be established. Autoregulation, the organ's ability to maintain consistent blood flow, plays a vital role in perfusion. Individual variability in autoregulation responses and intraoperative factors necessitate an individualized approach to determining the autoregulation range. Continuous assessment of autoregulation during surgery allows for personalized perfusion targets, optimizing organ perfusion. Exploring techniques like multimodal intravenous anesthesia guided by electroencephalogram can enhance perfusion maintenance within the auto-regulatory range. By adopting an individualized approach to perfusion targets on CPB, we can improve outcomes and enhance patient care.

Comparative analysis of early postoperative results of transcatheter aortic valve implantation and surgical aortic valve replacement with a biological prosthesis

OBJECTIVE

. Aim: The choice of aortic valve stenosis correction method is determined by a number of clinical and technical parameters. The task was to compare early postoperative outcomes in patients after correction of aortic valve stenosis using TAVI and surgical aortic valve replacement with a biological prosthesis.

PATIENTS AND METHODS

Materials and Methods: This retrospective study analyzed the medical records of adult patients (18 years of age and older) who had transcatheter aortic valve implantation or surgical aortic valve replacement with a biological prosthesis at the State Institution "Heart Institute of the Ministry of Health" in the period from 2018 to 2022.

RESULTS

Results: In 47 (47.5%) cases, TAVI was performed and in 52 (52.5%) cases, SAVR with a biological prosthesis was performed. Patients who underwent TAVI were significantly older (p=0.002) and had a higher EuroSCORE II operative risk score (p<0.001). In patients with TAVI, larger diameter aortic valve prostheses were significantly more often used compared with the SAVR group with biological prosthesis (27.5±2.74 vs. 22.5±1.84, p<0.001). The early postoperative period in patients with TAVI was characterized by an 11.4% (p=0.046) and 15.4% (p=0.006). The length of stay in the ICU (p=0.024), as well as the duration of hospitalization in general (p=0.005), was also significantly lower in patients with TAVI compared with patients with biological prosthesis SAVR.

CONCLUSION

Conclusions: Despite the higher surgical risk of surgery according to EuroSCORE II, TAVI was characterized by a lower incidence of postoperative complications, with shorter duration of stay in ICU and hospitalization in general in comparison with patients undergoing SAVR with a biological prosthesis.

The multifactorial dynamic perfusion index: A predictive tool of cardiac surgery associated acute kidney injury

INTRODUCTION

cardiac surgery associated acute kidney injury (CSA-AKI) has a number of preoperative and intraoperative risk factors. Cardiopulmonary bypass (CPB) factors have not yet been elucidated in a single multivariate model. The aim of this study is to develop a dynamic predictive model for CSA-AKI.

METHODS

retrospective study on 910 consecutive adult cardiac surgery patients. Baseline data were used to settle a preoperative CSA-AKI risk model (static risk model, SRM); CPB related data were assessed for association with CSA-AKI. CPB duration, nadir oxygen delivery, time of exposure to a low oxygen delivery, nadir mean arterial pressure, peak lactates and red blood cell transfusion were included in a multivariate dynamic perfusion risk (DPR). SRM and DPR were merged into a final logistic regression model (multifactorial dynamic perfusion index, MDPI). The three risk models were assessed for discrimination and calibration.

RESULTS

the SRM model had an AUC of 0.696 (95% CI 0.663-0.727), the DPR model of 0.723 (95% CI 0.691-0.753), and the MDPI model an AUC of 0.769 (95% CI 0.739-0.798). The difference in AUC between SRM and DPR was not significant (p = 0.495) whereas the AUC of MDPI was significantly larger than that of SRM (p = 0.004) and DPR (p = 0.015).

CONCLUSIONS

inclusion of dynamic indices of the quality of CPB improves the discrimination and calibration of the preoperative risk scores. The MDPI has better predictive ability than the existing static risk models and is a promising tool to integrate different factors into an advanced concept of goal-directed perfusion.

Association between intraoperative hyperglycemia/hyperlactatemia and acute kidney injury following on-pump cardiac surgery: a retrospective cohort study

Background

Despite the long-lasting notion about the substantial contribution of intraoperative un-stabilization of homeostasis factors on the incidence on acute kidney injury (AKI), the possible influence of intraoperative glucose or lactate management, as a modifiable factor, on the development of AKI remains inconclusive.

Objectives

To investigated the relationship between intraoperative hyperglycemia, hyperlactatemia, and postoperative AKI in cardiac surgery.

Methods

A retrospective cohort study was conducted among 4,435 adult patients who underwent on-pump cardiac surgery from July 2019 to March 2022. Intraoperative hyperglycemia and hyperlactatemia were defined as blood glucose levels >10 mmol/L and lactate levels >2 mmol/L, respectively. The primary outcome was the incidence of AKI. All statistical analyses, including t tests, Wilcoxon rank sum tests, chi-square tests, Fisher's exact test, Kolmogorov-Smirnov test, logistic regression models, subgroup analyses, collinearity analysis, and receiver operating characteristic analysis, were performed using the statistical software program R version 4.1.1.

Results

Among the 4,435 patients in the final analysis, a total of 734 (16.55%) patients developed AKI after on-pump cardiac surgery. All studied intraoperative metabolic disorders was associated with increased AKI risk, with most pronounced odds ratio (OR) noted for both hyperglycemia and hyperlactatemia were present intraoperatively [adjusted OR 3.69, 95% confidence intervals (CI) 2.68-5.13, p < 0.001]. Even when hyperglycemia or hyperlactatemia was present alone, the risk of postoperative AKI remained elevated (adjusted OR 1.97, 95% CI 1.50-2.60, p < 0.001).

Conclusion

The presence of intraoperative hyperglycemia and hyperlactatemia may be associated with postoperative acute kidney injury (AKI) in patients undergoing on-pump cardiac surgery. Proper and timely interventions for these metabolic disorders are crucially important in mitigating the risk of AKI.

Acute Kidney Injury after Cardiac Surgery: Prediction, Prevention, and Management

Acute kidney injury (AKI) is a common complication in cardiac surgery patients, with a reported incidence of 20 to 30%. The development of AKI is associated with worse short- and long-term mortality, and longer hospital length of stay. The pathogenesis of cardiac surgery-associated AKI is poorly understood but likely involves an interplay between preoperative comorbidities and perioperative stressors. AKI is commonly diagnosed by using increases in serum creatinine or decreased urine output and staged using a standardized definition such as the Kidney Disease Improving Global Outcomes classification. Novel biomarkers under investigation may provide earlier detection and better prediction of AKI, enabling mitigating therapies early in the perioperative period. Recent clinical trials of cardiac surgery patients have demonstrated the benefit of goal-directed oxygen delivery, avoidance of hyperthermic perfusion and specific fluid and medication strategies. This review article highlights both advances and limitations regarding the prevention, prediction, and treatment of cardiac surgery-associated AKI.

Quantifying the effects of circulatory arrest on acute kidney injury in aortic surgery

OBJECTIVES

We aim to investigate the association between parameters surrounding circulatory arrest and postoperative acute kidney injury in aortic surgery.

METHODS

This is a single-center retrospective study of 1118 adult patients who underwent aortic repair with median sternotomy between January 2010 and May 2019. Acute kidney injury was defined on the basis of a modified version of the 2012 Kidney Disease Improving Global Outcomes Scale that excluded urine output. The primary outcome of interest was any stage of acute kidney injury.

RESULTS

Circulatory arrest was required in 369 patients, and 307 patients (27.5%) developed acute kidney injury: stage 1 in 241 patients, stage 2 in 38 patients, and stage 3 in 28 patients. Lower-body ischemia (the period during circulatory arrest without blood flow to kidneys) duration was not associated with acute kidney injury after multivariable logistic regression (1-40 minutes, odds ratio, 0.67; 95% confidence interval, 0.43-1.04; P = .075; >40 minutes, odds ratio, 0.67; 95% confidence interval, 0.29-1.55; P = .356). Hypertension (odds ratio, 1.65; 95% confidence interval, 1.09-2.54; P = .020), preoperative estimated glomerular filtration rate (odds ratio, 0.99; 95% confidence interval, 0.98-1.00; P = .010), packed red blood cell transfusion volume (odds ratio, 1.00; 95% confidence interval, 1.00-1.00; P = .028), and nadir temperature (odds ratio, 0.93; 95% confidence interval, 0.88-0.99; P = .013) were independently associated with acute kidney injury after multivariable analysis. Although there was a positive association between lower-body ischemia duration and development of acute kidney injury with univariable cubic spline, the positive curve was flattened after adjustment for the described variables.

CONCLUSIONS

Within the range of our clinical practice, prolonged lower-body ischemia duration was not independently associated with postoperative acute kidney injury, whereas nadir temperature was.

Exogenous nitric oxide delivery protects against cardiopulmonary bypass-associated acute kidney injury: Histologic and serologic evidence from an ovine model

OBJECTIVE

Several human studies have associated nitric oxide administration via the cardiopulmonary bypass circuit with decreased incidence of cardiopulmonary bypass-associated acute kidney injury, but histopathologic and serologic evidence of nitric oxide efficacy for acute kidney injury attenuation are lacking.

METHODS

By using a survival ovine model (72 hours), acute kidney injury was induced by implementing low-flow cardiopulmonary bypass for 2 hours, followed by full-flow cardiopulmonary bypass for 2 hours. The nitric oxide cohort (n = 6) received exogenous nitric oxide through the cardiopulmonary bypass circuit via the oxygenator, and the control group (n = 5) received no nitric oxide. Serial serologic biomarkers and renal histopathology were obtained.

RESULTS

Baseline characteristics (age, weight) and intraoperative parameters (cardiopulmonary bypass time, urine output, heart rate, arterial pH, and lactate) were equivalent (P > .10) between groups. Postoperatively, urine output, heart rate, respiratory rate, and peripheral arterial saturation were equivalent (P > .10) between groups. Post-cardiopulmonary bypass creatinine elevations from baseline were significantly greater in the control group versus the nitric oxide group at 16, 24, and 48 hours (all P < .05). Histopathologic evidence of moderate/severe acute kidney injury (epithelial necrosis, tubular slough, cast formation, glomerular edema) occurred in 60% (3/5) of the control group versus 0% (0/6) of the nitric oxide group. Cortical tubular epithelial cilia lengthening (a sensitive sign of cellular injury) was significantly greater in the control group than in the nitric oxide group (P = .012).

CONCLUSIONS

In a survival ovine cardiopulmonary bypass model, nitric oxide administered with cardiopulmonary bypass demonstrated serologic and histologic evidence of renal protection from acute kidney injury. These results provide insight into 1 potential mechanism for cardiopulmonary bypass-associated acute kidney injury and supports continued study of nitric oxide via cardiopulmonary bypass circuit for prevention of acute kidney injury.

NO Addition during Gas Oxygenation Reduces Liver and Kidney Injury during Prolonged Cardiopulmonary Bypass

Objective. To evaluate the effect of NO added to the sweep gas of the oxygenator during cardiopulmonary bypass (CPB) on the liver and kidneys in pigs. Methods. An experiment was carried out on 10 pigs undergoing cardiac surgery using CPB. NO was added to the sweep gas of the oxygenator at a concentration of 100 ppm for the animals in the experimental group (CPB-NO, n = 5). Animals in the control group (CPB-contr, n = 5) did not receive NO in the sweep gas of the oxygenator. The CPB lasted 4 h, followed by postoperative monitoring for 12 h. To assess the injury to the liver and kidneys, the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, creatinine, and neutrophil gelatinase-associated lipocalin (NGAL) were determined initially, at weaning from the CPB, and 6 and 12 h after weaning from the CPB. The glomerular filtration rate (GFR) was evaluated initially, at weaning from the CPB, and 6 and 12 h after weaning from the CPB. A pathomorphological study of the liver and kidneys was performed using semiquantitative morphometry. Results. The long four-hour period of CPB deliberately used in our experiment caused liver and kidney injury. In the CPB-contr group, an increase in the ALT concentration was found: 43 (34; 44) U/L at baseline to 82 (53; 99) U/L 12 h after CPB, p < 0.05. The AST concentration in the CPB-contr group increased from 25 (17; 26) U/L at baseline to 269 (164; 376) U/L 12 h after CPB, p < 0.05. We found no significant increase in the ALT and AST concentrations in the CPB-NO group. There were no significant differences in ALT and AST concentrations between the CPB-NO and CPB-contr groups at all the study time-points. In the CPB-contr group, an increase in the creatinine level was found from 131 (129; 133) µmol/L at baseline to 273 (241; 306) µmol/L 12 h after CPB, p < 0.05. We found no significant increase in creatinine level in the CPB-NO group. Creatinine levels in the CPB-NO group were significantly lower than in the CPB-contr group 12 h after weaning from CPB: 183 (168; 196) vs. 273 (241; 306) µmol/L; p = 0.008. The GFR in the CPB-NO group was significantly higher than in the CPB-contr group 6 h after weaning from CPB: 78.9 (77.8; 82.3) vs. 67.9 (62.3; 69.2) mL/min; p = 0.016. GFR was significantly higher in the CPB-NO group than in the CPB-contr group 12 h after weaning from CPB: 67.7 (65.5; 68.0) vs. 50.3 (48.7; 54.9) mL/min; p = 0.032. We found no significant differences between the study groups in the level of NGAL. We found several differences between the groups in the pathomorphological study. Conclusions. NO added to the sweep gas of the oxygenator reduces creatinine levels and increases GFR during prolonged CPB injury. Further research is required.

Prediction of acute kidney injury following coronary artery bypass graft surgery in elderly Chinese population

BACKGROUND

Acute kidney injury (AKI) is a common and serious complication following coronary artery bypass graft (CABG) surgery. Advanced age is an independent risk factor for the development of AKI, and the incidence of AKI in the elderly increases more rapidly than that in younger patients. This study aimed to develop and validate the risk prediction model for AKI after CABG in elderly patients.

METHODS

Patients were retrospectively recruited from January 2019 to December 2020. AKI after CABG was defined according to the criteria of Kidney Disease Improving Global Outcomes (KDIGO). The entire population was divided into the derivation set and the verification set using random split sampling (ratio: 7:3). Lasso regression method was applied to screen for the variables in the derivation set. Decision curve analysis (DCA) and receiver operating characteristic (ROC) curves were plotted to analyze the predictive ability of the model for AKI risk in the derivation set and the verification set.

RESULTS

A total of 2155 patients were enrolled in this study. They were randomly divided into the derivation set (1509 cases) and the validation set (646 cases). Risk factors associated with AKI were selected by Lasso regression including T2DM, diabetes mellitus type intraoperative use of intra-aortic ballon pump (IABP), cardiopulmonary bypass (CPB), epinephrine, isoprenaline, and so on. The model was established by Lasso logistic regression. The area under the ROC curve (AUC) of the model for the derivation set was 0.754 (95% CI: 0.720 - 0.789), and that for the validation cohort was 0.718 (95% CI: 0.665 - 0.771).

CONCLUSION

In this study, the model with significant preoperative and intraoperative variables showed good prediction performance for AKI following CABG in elderly patients to optimize postoperative treatment strategies and improve early prognosis.

High level of intraoperative lactate might predict acute kidney injury in aortic arch surgery via minimally invasive approach in patients with type A dissection

Background

A high incidence of acute kidney injury (AKI) has been recorded in total arch replacement (TAR) combined with frozen elephant trunk (FET) implantation in patients with acute type A dissection (ATAAD) via median sternotomy approach with some risk factors. However, the independent risk factors for AKI via a minimally invasive approach have not yet been identified.

Methods

A total of 207 patients with ATAAD were enrolled from January 2018 and November 2019 and were divided into AKI and non-AKI groups. The current surgical strategy was TAR combined with FET via a single upper hemisternotomy approach, a minimally invasive method. An increase in the serum creatinine (Cr) level to ≥2 times the baseline level 48 h post-surgery was defined as AKI. The morbidity of AKI was investigated with a step-by-step backward multivariate analysis of its independent risk factors and a receiver-operating characteristic curve analysis.

Results

Postoperative AKI was observed in 39 (18.8%) patients, and the total hospital mortality was 8.7%. Univariate analysis found that preoperative Cr, weight, circulatory arrest time ≥60 min, intraoperative highest lactate (Lac), and intraoperative transfusion had significant differences between the two groups. However, multivariate step-by-step backward logistic regression analysis identified intraoperative highest Lac and transfusion as independent risk factors for postoperative AKI and intraoperative highest Lac was identified as the most critical independent risk factor estimated by the partial chi-square statistic minus the predicted degrees of freedom with 4.3 mmol/L as the optimal cut-off point for prediction for AKI.

Conclusions

Intraoperative highest Lac and transfusion were independent risk factors for postoperative AKI, which led to high hospital mortality. Moreover, intraoperative highest Lac was the most critical independent risk factor and high level of intraoperative highest Lac (4.3 mmol/L) might predict for postoperative AKI.

Effect of Dexmedetomidine on Postoperative Renal Function in Patients Undergoing Cardiac Valve Surgery Under Cardiopulmonary Bypass: A Randomized Clinical Trial

OBJECTIVE

The effect of dexmedetomidine on postoperative renal function was investigated in patients undergoing cardiac valve surgery under cardiopulmonary bypass (CPB).

DESIGN

A randomized controlled trial.

SETTING

University teaching, grade A tertiary hospital.

PARTICIPANTS

A total of 70 patients scheduled to undergo cardiac valve replacement or valvuloplasty under CPB were eligible and randomly divided into groups D (n = 35) and C (n = 35) between January 2020 and March 2021.

INTERVENTIONS

Patients in group D were administered 0.6 μg/kg/h of dexmedetomidine intravenously from 10 minutes before anesthesia induction to 6 hours after surgery; normal saline was used instead of dexmedetomidine in group C.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the incidence of acute kidney injury (AKI). Acute kidney injury was defined according to the Kidney Disease Improving Global Outcomes (2012). It was 22.86% and 48.57% in groups D and C, respectively (p = 0.025). The secondary outcomes were intraoperative hemodynamics and various indices in serum. Ten minutes before CPB (T₁), 10 minutes after CPB (T₂), and 30 minutes after CPB (T₃), mean arterial pressure in group D was lower than that in group C, with statistical significance (74.94 ± 8.52 v 81.89 ± 13.66 mmHg, p=0.013; 62.83 ± 11.27 v 71.86 ± 7.89 mmHg, p < 0.001; 72.26 ± 8.75 v 78.57 ± 8.83 mmHg, p = 0.004). At T₁, the heart rate in group D was significantly lower than in group C (80.89 ± 14.04 v 95.54 ± 12.53 bpm, p=0.022). The tumor necrosis factor α, interleukin-6, C-reactive protein, and cystatin C levels in group D were lower than those in group C after the surgery (T₄) and 24 hours after surgery (T₅), with statistical significance. The duration of mechanical ventilation, intensive-care-unit stay time, and hospital stay time in group D were significantly shorter than in group C. The incidences of tachycardia, hypertension, nausea, and vomiting in group D were similar to those in group C.

CONCLUSIONS

Dexmedetomidine may be considered as a way to reduce the incidence and severity of postoperative AKI in patients undergoing cardiac valve surgery under cardiopulmonary bypass.

Goal-directed perfusion for reducing acute kidney injury in cardiac surgery: A systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is a common complication following cardiopulmonary bypass (CPB) which can affect morbidity and mortality. Goal-directed perfusion (GDP) intended to avoid the nadir oxygen delivery index below the critical value is associated with reduced postoperative AKI. However, current studies suggested that GDP can only decrease the incidence of AKI stage 1 but showed no effects on AKI stages 2-3 and mortality. The objective of the present meta-analysis is to deter the effects of GDP on postoperative AKI in any stage and mortality following cardiac surgery.

METHODS

MEDLINE, Embase, and the Cochrane Library were searched to identify all clinical trials comparing GDP with control (standard care) during cardiopulmonary bypass conducting in adults undergoing cardiac surgery. The primary outcome was postoperative acute kidney injury. Secondary outcomes included postoperative mortality and length of ICU stay. Data synthesis was obtained by using risk ratio with 95% confidence interval by a random-effects model.

RESULT

From 1094 potential studies, 3 trials enrolling 777 patients were included. Meta-analysis suggested the GDP strategy based on DO₂i reduced postoperative AKI compared with standard CPB management (RR = 0.52; 95% CI: 0.38-0.70; p < .0001), especially in AKI stage I (RR = 0.47; 95% CI: 0.33-0.66; p < .0001). But the GDP strategy did not reduce the incidence of severe AKI (stages 2-3) and postoperative mortality.

CONCLUSION

The GDP strategy based on DO₂i during CPB obviously reduces AKI stage 1 and thus reduces overall AKI incidence. But it shows no effects on severe AKI (stages 2-3) and mortality.

Acute Kidney Injury After General Thoracic Surgery: A Systematic Review and Meta-Analysis

INTRODUCTION

The clinical importance of postoperative acute kidney injury (AKI) in patients undergoing general thoracic surgery is unclear. We aimed to systematically review the incidence, risk factors, and prognostic implications of AKI as a complication after general thoracic surgery.

METHODS

We searched PubMed, EMBASE, and the Cochrane Library from January 2004 to September 2021. Observational or interventional studies that enrolled ≥50 patients undergoing general thoracic surgery and reported postoperative AKI defined using contemporary consensus criteria were included for meta-analysis.

RESULTS

Thirty-seven articles reporting 35 unique cohorts were eligible. In 29 studies that enrolled 58,140 consecutive patients, the pooled incidence of postoperative AKI was 8.0% (95% confidence interval [CI]: 6.2-10.0). The incidence was 3.8 (2.0-6.2) % after sublobar resection, 6.7 (4.1-9.9) % after lobectomy, 12.1 (8.1-16.6) % after bilobectomy/pneumonectomy, and 10.5 (5.6-16.7) % after esophagectomy. Considerable heterogeneity in reported incidences of AKI was observed across studies. Short-term mortality was higher (unadjusted risk ratio: 5.07, 95% CI: 2.99-8.60) and length of hospital stay was longer (weighted mean difference: 3.53, 95% CI: 2.56-4.49, d) in patients with postoperative AKI (11 studies, 28,480 patients). Several risk factors for AKI after thoracic surgery were identified.

CONCLUSIONS

AKI occurs frequently after general thoracic surgery and is associated with increased short-term mortality and length of hospital stay. For patients undergoing general thoracic surgery, AKI may be an important postoperative complication that needs early risk evaluation and mitigation.

Interleukin-33 Mediates Cardiomyopathy After Acute Kidney Injury by Signaling to Cardiomyocytes

BACKGROUND

Acute kidney injury (AKI) is a short-term life-threatening condition that, if survived, can lead to renal insufficiency and development of chronic kidney disease. The pathogenesis of AKI and chronic kidney disease involves direct effects on the heart and the development of hypertrophy and cardiomyopathy.

METHODS

We used mouse models of ischemia/reperfusion AKI and unilateral ureteral obstruction to investigate the role of IL-33 (interleukin-33) and its receptor-encoding gene Il1rl1 (also called ST2L [suppression of tumorigenicity 2]) in cardiac remodeling after AKI. Mice with cell type-specific genetic disruption of the IL-33/ST2L axis were used, and IL-33 monoclonal antibody, adeno-associated virus encoding IL-33 or ST2L, and recombinant IL-33, as well.

RESULTS

Mice deficient in Il33 were refractory to cardiomyopathy associated with 2 models of kidney injury. Treatment of mice with monoclonal IL-33 antibody also protected the heart after AKI. Moreover, overexpression of IL-33 or injection of recombinant IL-33 induced cardiac hypertrophy or cardiomyopathy, but not in mice lacking Il1rl1. AKI-induced cardiomyopathy was also reduced in mice with cardiac myocyte-specific deletion of Il1rl1 but not in endothelial cell- or fibroblast-specific deletion of Il1rl1. Last, overexpression of the ST2L receptor in cardiac myocytes recapitulated induction of cardiac hypertrophy.

CONCLUSIONS

These results indicate that IL-33 released from the kidney during AKI underlies cardiorenal syndrome by directly signaling to cardiac myocytes, suggesting that antagonism of IL-33/ST2 axis would be cardioprotective in patients with kidney disease.

Biomarkers of eGFR decline after cardiac surgery in children: findings from the ASSESS-AKI study

BACKGROUND

Children who require surgery for congenital heart disease have increased risk for long-term chronic kidney disease (CKD). Clinical factors as well as urine biomarkers of tubular health and injury may help improve the prognostication of estimated glomerular filtration rate (eGFR) decline.

METHODS

We enrolled children from 1 month to 18 years old undergoing cardiac surgery in the ASSESS-AKI cohort. We used mixed-effect models to assess the association between urinary biomarkers (log2-transformed uromodulin, NGAL, KIM-1, IL-18, L-FABP) measured 3 months after cardiac surgery and cyanotic heart disease with the rate of eGFR decline at annual in-person visits over 4 years.

RESULTS

Of the 117 children enrolled, 30 (24%) had cyanotic heart disease. During 48 months of follow-up, the median eGFR in the subgroup of children with cyanotic heart disease was lower at all study visits as compared with children with acyanotic heart disease (p = 0.01). In the overall cohort, lower levels of both urine uromodulin and IL-18 after discharge were associated with eGFR decline. After adjustment for age, RACHS-1 surgical complexity score, proteinuria, and eGFR at the 3-month study visit, lower concentrations of urine uromodulin and IL-18 were associated with a monthly decline in eGFR (uromodulin β = 0.04 (95% CI: 0.00-0.09; p = 0.07) IL-18 β = 0.07 (95% CI: 0.01-0.13; p = 0.04), ml/min/1.73 m² per month).

CONCLUSIONS

At 3 months after cardiac surgery, children with lower urine uromodulin and IL-18 concentrations experienced a significantly faster decline in eGFR. Children with cyanotic heart disease had a lower median eGFR at all time points but did not experience faster eGFR decline. A higher-resolution version of the Graphical abstract is available as Supplementary information.

Risk factors of perioperative acute kidney injury in elderly patients: a single-center retrospective study

PURPOSE

The elderly are vulnerable to perioperative acute kidney injury. The aim of this study was to determine the risk factors that associated with acute kidney injury among elderly patients.

METHODS

Clinical data of elderly patients (> 65 years) who underwent noncardiac, nonrenal surgery between Dec 1 2009 and July 1 2016 were collected for this single-centered historical cohort study. Univariate and multivariate analyses were conducted to explore the risk factors that contribute to acute kidney injury, which was defined as a serum creatinine increase >0.3 mg/dL within 48 h or 1.5 times increase in serum creatinine within 7 days after surgery.

RESULTS

7775 patients were eligible for the final analysis, among which 511 (6.57%) patients developed acute kidney injury. We observed 21 risk factors being associated with perioperative acute kidney injury, with the most important disposing factors being history of kidney disease (adjusted OR = 2.94, 95% CI 2.25-3.84), operation time > 180 min (aOR = 2.93, 95% CI 2.04-4.24), preoperative eGFR [15, 30) (aOR = 2.43, 95% CI 1.29-4.45), and protective factor being intraoperative use of sufentanil (aOR = 0.35, 95% CI 0.23-0.54).

CONCLUSION

This study determined risk factors for perioperative acute kidney injury among the elderly in the Second Xiangya Hospital and visualized the risk factors using nomogram and Excel calculator, which may provide some clues to further investigations. Overall, the prevalence of AKI among this large cohort is 6.57%.

CLINICAL TRIALS REGISTRATION

http://www.chictr.org.cn ; ChiCTR1900027007; October 28, 2019.

Oxygen delivery-guided perfusion for the prevention of acute kidney injury: A randomized controlled trial

OBJECTIVES

The reduction of postoperative acute kidney injury in patients undergoing cardiopulmonary bypass surgery using an oxygen delivery-guided perfusion strategy (oxygen delivery strategy) for cardiopulmonary bypass management compared with a fixed flow perfusion (conventional strategy) remains controversial. The purpose of this study was to determine whether a oxygen delivery strategy would reduce the incidence of postoperative acute kidney injury in patients undergoing cardiopulmonary bypass surgery.

METHODS

We randomly enrolled 300 patients undergoing cardiopulmonary bypass surgery. Patients were randomly assigned to a oxygen delivery strategy (maintaining a oxygen delivery index value >300 mL/min/m² through pump flow adjustments during cardiopulmonary bypass) or a conventional strategy (a target pump flow was determined on the basis of the body surface area). The primary end point was the development of acute kidney injury. Secondary end points were the red blood cell transfusion rate and number of red blood cell units, intubation time, postoperative length of stay in the intensive care unit and the hospital, predischarge estimated glomerular filtration rate, and hospital mortality.

RESULTS

Acute kidney injury occurred in 20 patients (14.6%) receiving the oxygen delivery strategy and in 42 patients (30.4%) receiving the conventional strategy (relative risk, 0.48; 95% confidence interval, 0.30-0.77; P = .002). The secondary end points were not significantly different between strategies. In a prespecified subgroup analysis of patients who had nadir hematocrit less than 23% or body surface area less than 1.40 m², the oxygen delivery strategy seemed to be superior to the conventional strategy and the existence of quantitative interactions was suggested.

CONCLUSIONS

An oxygen delivery strategy for cardiopulmonary bypass management was superior to a conventional strategy with respect to preventing the development of acute kidney injury.

Prion Protein Overexpression in Adipose-Derived Mesenchymal Stem Cells (ADMSCs) Effectively Protected Rodent Kidney Against Ischemia-Reperfusion Injury Via Enhancing ATP/Mitochondrial Biogenesis-Role of ADMSC Rejuvenation and Proliferation

BACKGROUND

We tested the hypothesis that overexpression of cellular-prion-protein in adipose-derived mesenchymal stem cells (PrPCOE-ADMSCs) effectively protected the kidney against ischemia-reperfusion (IR) injury in rat.

METHODS

Part I of cell culture was categorized into A1(ADMSCs)/A2(ADMSCs+p-Cresol)/A3(PrPCOE in ADMSCs)/A4 (PrPCOE in ADMSCs+p-Cresol). Part II of cell culture was divided into B1(ADMSCs)/B2[ADMSCs+lipopolysaccharide (LPS)]/B3(PrPCOE in ADMSCs)/B4(PrPCOE in ADMSCs+LPS). Sprague-Dawley (SD) rats (n = 50) were equally categorized into groups 1 (sham-operated-control)/2 (IR)/3 (IR+ADMSCs/6.0 × 105 equally divided into bilateral-renal arteries and 6.0 × 105 intravenous administration by 1 h after IR)/4 [IR+PrPCOE-ADMSCs (identical dosage administered as group 3)]/5 [IR+silencing PRNP -ADMSCs (identical dosage administered as group 3)], and kidneys were harvested post-day 3 IR injury.

RESULTS

Part I results demonstrated that the cell viability at 24/48/72 h, BrdU uptake/number of mitDNA/APT concentration/mitochondrial-cytochrome-C+ cells and the protein expressions of ki67/PrPC at 72 h-cell culturing were significantly higher in PrPCOE-ADMSCs than in ADMSCs (all P < 0.001). The protein expressions of oxidative-stress (NOX-1/NOX2/NOX4/oxidized protein)/mitochondrial-damaged (p22-phox/cytosolic-cytochrome-C)/inflammatory (p-NF-κB/IL-1ß/TNF-α/IL-6)/apoptotic (cleaved caspase-3/cleaved-PARP) biomarkers were lowest in A1/A3 and significantly higher in A2 than in A4 (all P < 0.001). Part II result showed that the protein expressions of inflammatory (p-NF-κB/IL-1ß/TNF-α/IL-6)/apoptotic (cleaved caspase-3/cleaved-PARP) biomarkers exhibited an identical pattern of part I among the groups (all P < 0.001). The protein expressions of inflammatory (p-NF-κB/IL-1ß/TNF-α/MMP-9)/oxidative-stress (NOX-1/NOX-2/oxidized-protein)/mitochondrial-damaged (cytosolic-cytochrome-C/p22-phox)/apoptotic (cleaved caspase-3/cleaved-PARP/mitochondrial-Bx)/autophagic (beclin-1/ratio of LC3B-II/LC3B-I)/fibrotic (Smad3/TGF-ß) biomarkers and kidney-injury-score/creatinine level were lowest in group 1, highest in group 2, significantly higher in group 5 than in groups 3/4 (all P < 0.0001).

CONCLUSION

PrPCOE in ADMSCs rejuvenated these cells and played a cardinal role on protecting the kidney against IR injury.

Predicting Risk Factors of Acute Kidney Injury in the First 7 Days after Admission: Analysis of a Group of Critically Ill Patients

Background

Acute kidney injury (AKI) is a common complication in critically ill patients. Some predictive models have been reported, but the conclusions are controversial. The aim of this study was the formation of nomograms to predict risk factors for AKI in critically ill patients within the first 7 days after admission to the intensive care unit (ICU).

Methods

Data were extracted from the Medical Information Mart for Intensive Care- (MIMIC-) III database. The random forest method was used to fill in the missing values, and least absolute shrinkage and selection operator (Lasso) regression analysis was performed to screen for possible risk factors.

Results

A total of 561 patients were enrolled. Complication with AKI is significantly associated with a longer length of stay (LOS). For all patients, the predictors contained in the prediction nomogram included hypertension, coronary artery disease (CAD), cardiopulmonary bypass (CPB), coronary artery bypass grafting (CABG), Simplified Acute Physiology Score II (SAPS II), central venous pressure (CVP) measured for the first time after admission, and maximum and minimum mean artery pressure (MAP). The model showed good discrimination (C - index = 0.818, 95% CI: 0.779-0.857). In the subgroup of patients with well-controlled blood glucose levels, the significant predictors included hypertension, CABG, CPB, SAPS II, and maximum and minimum MAP. Good discrimination was also present before (C - index = 0.785, 95% CI: 0.736-0.834) and after adjustment (adjusted C - index = 0.770).

Conclusion

Hypertension, CAD, CPB, CABG, SAPS II, CVP measured for the first time after admission, and maximum and minimum MAP were independent risk factors for AKI in critically ill patients.

Association of Preoperative Pulse Pressure and Oxygen Delivery Index During Cardiopulmonary Bypass With Postoperative Acute Kidney Injury

OBJECTIVE

To investigate if oxygen delivery index during cardiopulmonary bypass (DO₂I) was more strongly associated with acute kidney injury (AKI), the higher the patient's preoperative pulse pressure (PP).

DESIGN

Retrospective cohort of 1064 patients undergoing cardiac surgery.

SETTING

Single academic healthcare center.

PARTICIPANTS

Adult patients undergoing coronary artery bypass grafting, valve, aortic, or combined surgery requiring cardiopulmonary bypass.

INTERVENTIONS

Hemoglobin, arterial oxygen saturation, and pump flow recorded no fewer than every 30 min were extracted from the patients' perfusion records, and DO₂I was calculated. The AKI was assessed from the pre- and postoperative creatinine and urine output values using the Acute Kidney Injury Network criteria. The sample was stratified in 5 categories of progressively higher PP. The patient characteristics and intraoperative variables were evaluated in univariate analysis for a relationship with AKI. The significant risk factors from the univariate analysis then were evaluated in a multivariate analysis and assessed for logistic fit with respect to AKI.

PRIMARY OUTCOME

The AKI assessed as a binary outcome.

MEASUREMENTS AND MAIN RESULTS

Age, body surface area, DO₂I, history of heart failure, and baseline creatinine were associated significantly with AKI, as was an interaction term between the PP category and DO₂I (p = 0.0067). The higher the PP category, the stronger the observed association between DO₂I and AKI, and the higher the variability in the predicted risk of AKI dependent on DO₂I.

CONCLUSIONS

A lower DO₂I during cardiopulmonary bypass appeared more strongly associated with a higher likelihood of developing AKI, the higher the patient's preoperative pulse pressure.

Limited clinical utility for GWAS or polygenic risk score for postoperative acute kidney injury in non-cardiac surgery in European-ancestry patients

BACKGROUND

Prior studies support a genetic basis for postoperative acute kidney injury (AKI). We conducted a genome-wide association study (GWAS), assessed the clinical utility of a polygenic risk score (PRS), and estimated the heritable component of AKI in patients who underwent noncardiac surgery.

METHODS

We performed a retrospective large-scale genome-wide association study followed by a meta-analysis of patients who underwent noncardiac surgery at the Vanderbilt University Medical Center ("Vanderbilt" cohort) or Michigan Medicine, the academic medical center of the University of Michigan ("Michigan" cohort). In the Vanderbilt cohort, the relationship between polygenic risk score for estimated glomerular filtration rate and postoperative AKI was also tested to explore the predictive power of aggregating multiple common genetic variants associated with AKI risk. Similarly, in the Vanderbilt cohort genome-wide complex trait analysis was used to estimate the heritable component of AKI due to common genetic variants.

RESULTS

The study population included 8248 adults in the Vanderbilt cohort (mean [SD] 58.05 [15.23] years, 50.2% men) and 5998 adults in Michigan cohort (56.24 [14.76] years, 49% men). Incident postoperative AKI events occurred in 959 patients (11.6%) and in 277 patients (4.6%), respectively. No loci met genome-wide significance in the GWAS and meta-analysis. PRS for estimated glomerular filtration rate explained a very small percentage of variance in rates of postoperative AKI and was not significantly associated with AKI (odds ratio 1.050 per 1 SD increase in polygenic risk score [95% CI, 0.971-1.134]). The estimated heritability among common variants for AKI was 4.5% (SE = 4.5%) suggesting low heritability.

CONCLUSION

The findings of this study indicate that common genetic variation minimally contributes to postoperative AKI after noncardiac surgery, and likely has little clinical utility for identifying high-risk patients.

Cardiac Surgery-associated Acute Kidney Injury in Patients with Preserved Baseline Renal Function

INTRODUCTION

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a powerful predictor of perioperative outcomes. We evaluated the burden of CSA-AKI in patients with preserved baseline renal function.

METHODS

The data of 2,162 adult patients who underwent cardiac surgery from January 2005 to December 2020 were analyzed. Logistic regression models were used to determine predictors of CSA-AKI and their associations with hospital mortality up to 30 days.

RESULTS

The prevalence of acute kidney injury was 43.0%, and 2.0% of patients required renal replacement therapy. Hospital mortality rate was 5.6% (non-acute kidney injury = 2.0% vs. CSA-AKI = 10.4%, P&lt;0.001), and any degree of CSA-AKI was associated with a significant increase in death rates (stage 1 = 4.3%, stage 2 = 23.9%, stage 3 = 59.7%). Multivariable logistic regression analysis identified age, obesity, left ventricular dysfunction, previous cardiac surgery, and cardiopulmonary bypass duration as predictors of CSA-AKI. Moreover, CSA-AKI was confirmed as independent predictor of hospital mortality for stage 1 (odds ratio, 2.02; 95% confidence interval, 1.16 to 3.51; P=0.013), stage 2 (odds ratio, 9.18; 95% confidence interval, 4.54 to 18.58; P&lt;0.001), and stage 3 (odds ratio, 37.72; 95% confidence interval, 18.87 to 75.40; P&lt;0.001) patients.

CONCLUSION

Age, obesity, left ventricular dysfunction, previous cardiac surgery, and cardiopulmonary bypass duration are independent predictors of CSA-AKI in patients with preserved baseline renal function. The development of CSA-AKI is significantly associated with worse outcomes, and there is a dose-response relationship between acute kidney injury stages and hospital mortality.

Multicentre evaluation of renal impairment in thoracic surgery (MERITS): a retrospective cohort study

OBJECTIVES

To measure the unit-level variation in Acute Kidney Injury (AKI) incidence post-thoracic surgery over a contemporary 1-year period. Secondary aims include examining the associations with sex, age group, operation type, length of stay and mortality.

DESIGN

A multicentre, observational, retrospective study in thoracic surgery.

SETTING

17 of 35 Society for Cardiothoracic Surgery of Great Britain and Ireland (SCTS) units participated. The student wing, known as SCTS STUDENTS, supported data collection.

PARTICIPANTS

Overall, 15 229 patients were collected of which 15 154 were included for analysis after exclusions. All patients (age≥18 years) undergoing any thoracic surgery from 1 April 2016 to 31 March 2017 were included. For analysis, we excluded patients with preoperative end-stage renal failure and those with incomplete data.

MAIN OUTCOME MEASURES

The primary outcome is the incidence of AKI within 7 days of the procedure or discharge date if earlier. Secondary outcomes include assessing associations with patient demographics (age, sex), type of procedure (open and minimally invasive), length of stay and mortality.

RESULTS

Out of 15 154 patients AKI was diagnosed in 1090 patients (7.2%) within 7 days of surgery with AKI stage 1 (4.8%), stage 2 (1.7%) and stage 3 (0.7%). There was a statistically significant variation in AKI incidence between units from 3.1 to 16.1% (p<0.05). Significant differences between AKI and non-AKI were found in post-operative length of stay (7 vs 3 days, p<0.001), 30-day mortality (9 vs 1.6%, p<0.001), 90-day mortality (14.7 vs 4.4%, p<0.001) and 1-year mortality (23.1 vs 12.2 %, p<0.001).

CONCLUSIONS

Following thoracic surgery, AKI incidence ranged from 3.1% to 16.1% between units (p<0.05) with associations between AKI and both length of stay and mortality. We propose AKI as a suitable comparative and absolute quality measure in thoracic surgery. Reducing rates of AKI may improve patient outcomes, length of stay and reduce costs.

The effects of hydroxyethyl starch 130/0.4 on perioperative renal function in patients undergoing cardiac surgery: A randomised controlled trial

Background

Acute kidney injury (AKI) after cardiac surgery increases the risk of morbidity and mortality. Hydroxyethyl starch (HES) is often used during surgery due to its plasma-volume expanding effect, but the impact of HES 130/0.4 on renal function in patients undergoing cardiac surgery remains unclear. The aim of our study is to investigate the impact of HES 130/0.4 on postoperative renal function in patients undergoing cardiac surgery using cardiopulmonary bypass.

Methods

Our study was a randomised, single-center, single-blind study conducted on 60 adult patients who underwent cardiac surgery using cardiopulmonary bypass: 30 patients were intraoperatively administered with HES 130/0.4; the other 30 with Ringer's bicarbonate. The primary endpoints were occurrence of AKI within 30 days of surgery and the disease stages.

Results

The mean dose of 6% HES 130/0.4 was 28 ml/kg. AKI occurred within 30 days of the operation in 8 cases (28.6%) in the HES group and 6 cases (21.4%) in the crystalloid group (no significance: p = 0.5371). Disease stages were as follows: “no AKI”, “stage 1”, “stage 2″ and “stage 3″, accounting for 20 cases (71.5%), 6 cases (21,4%), 2 cases (7.1%), and 0 cases, respectively, in the HES group, and 22 cases (78.6%), 6 cases (21.4%), 0 cases, and 0 cases, respectively, in the crystalloid group (no significance: p = 0.3508).

Conclusion

There was no significant difference in the occurrences or stages of AKI during the 30 days following cardiac surgery with cardiopulmonary bypass between patients administered with HES 130/0.4 or Ringer's bicarbonate.

•

Hydroxyethyl starch 130/0.4 is an effective plasma-volume expander.

•

Hydroxyethyl starch has a potential renal toxicity in cardiac surgery.

•

Acute kidney injury after cardiac surgery increases the risk of mortality.

•

Administration of hydroxyethyl starch 130/0.4 or crystalloid in cardiac surgery.

•

No difference in the occurrences or stages of acute kidney injury between groups.

Acute kidney injury following cardiopulmonary bypass in Jamaica

Objectives

The study objectives were to describe the incidence, risk factors, and outcomes of acute kidney injury after cardiopulmonary bypass in Jamaica.

Method

We performed a review of the medical records of adult patients (aged ≥ 18 years) with no prior dialysis requirement undergoing cardiopulmonary bypass at the University Hospital of the West Indies, Mona, between January 1, 2016, and June 30, 2019. Demographic, preoperative, intraoperative, and postoperative data were abstracted. Acute kidney injury was defined using Kidney Disease Improving Global Outcomes criteria. The primary outcomes were acute kidney injury incidence and all-cause 30-day mortality. Multivariable logistic regression and Cox proportional analyses were used to examine the association between the acute kidney injury risk factors and the primary outcome.

Results

Data for 210 patients (58% men, mean age 58.1 ± 12.9 years) were analyzed. Acute kidney injury occurred in 80 patients (38.1%), 44% with Kidney Disease Improving Global Outcomes I, 33% with Kidney Disease Improving Global Outcomes II, and 24% with Kidney Disease Improving Global Outcomes III. From multivariable logistic regression models, European System for Cardiac Operative Risk Evaluation II (odds ratio, 1.19; 95% confidence interval, 1.01-1.39 per unit), bypass time (odds ratio, 1.94; 95% confidence interval, 1.40-2.67 per hour), perioperative red cell transfusion (odds ratio, 3.03; 95% confidence interval, 1.36-6.76), and postoperative neutrophil lymphocyte ratio (odds ratio, 1.65; 95% confidence interval, 1.01-2.68 per 10-unit difference) were positively associated with acute kidney injury. Acute kidney injury resulted in greater median hospital stay (18 vs 11 days, P < .001) and intensive care unit stay (5 vs 3 days, P < .001), and an 8-fold increase in 30-day mortality (hazard ratio, 8.15; 95% confidence interval, 2.76-24.06, P < .001).

Conclusions

Acute kidney injury after cardiopulmonary bypass surgery occurs frequently in Jamaica and results in poor short-term outcomes. Further studies coupled with quality interventions to reduce the mortality of those with acute kidney injury are needed in the Caribbean.

Monitoring of intraoperative femoral oxygenation predicts acute kidney injury after pediatric cardiac surgery

Cardiopulmonary bypass-associated acute kidney injury (CPB-AKI) is a pediatric cardiac surgery postoperative complication that is associated with a longer duration of mechanical ventilation and length of hospital stay. Identifying an early predictor of CPB-AKI is critical. Near infrared spectroscopy (NIRS), which can provide real-time monitoring of regional tissue oxygen saturation (rSO₂) during CPB, may predict CPB-AKI in an early phase of surgical treatment. This study analyzed clinical data from 87 children who underwent an elective surgical repair of ventricular septal defect (VSD) from January 2013 to March 2019. NIRS sensors were placed on the patients' forehead, abdomen, and thighs. The pediatric modified risk, injury, failure, loss, and end-stage (p-RIFLE) score was determined for each patient postoperatively. The incidence of AKI based on the p-RIFLE classification was 11.5% at the end of surgery, 23.0% at 24 h after surgery, and 5.7% at 48 h after surgery. The AKI incidence rate was highest at 24 h after surgery. Multiple regression analysis revealed that femoral oxygenation (rSO₂) during CPB, CPB time, oxygen delivery index (DO₂i), and lactate at the end of CPB were independent risk factors for AKI. Receiver-operating characteristic curve analysis indicated that femoral oxygenation of 74% or less predicted AKI development within 24 h after surgery. In conclusion, rSO₂ measured at the thigh during CPB is highly predictive of CPB-AKI.

Preoperative Neutrophil-Lymphocyte Ratio for predicting surgery-related acute kidney injury in non-cardiac surgery patients under general anaesthesia: A retrospective cohort study

Background

This study was conducted to investigate the relationship between the Neutrophil-Lymphocyte Ratio (NLR) and the incidence of surgery-related acute kidney injury (AKI) in non-cardiac surgery patients under general anaesthesia.

Methods

In this retrospective study, 5057 patients from Third Xiangya hospital from January 2012 to December 2016 and 1686 patients from Second Xiangya hospital from January 2016 to December 2016 for non-cardiac surgery under general anesthesia were included. According to receiver operating characteristic (ROC) curve constructed by NLR for postoperative AKI, the cut-off point was obtained as the basis for grouping low or high NLR. The baseline characteristics of two sets were compared with each other. A multi-factor model was constructed by Least absolute shrinkage and selection operator (LASSO) method with the training set, and verified by outside validation set.

Results

243 patients (3.604%) developed postoperative AKI. The ROC curve showed that the AUC of the NLR for predicting postoperative AKI in non-cardiac surgery was 0.743 (95% CI, 0.717–0.769), and the cut-off value was 3.555 (sensitivity, 86.4%; specificity 51.9%). There was no significant difference in the baseline characteristics of training set and validation set. The AUC in the training set was 0.817 (95% CI, 0.784–0.850), and the AUC in the validation set was 0.804 (95% CI, 0.749–0.858), the AUC deviation was 0.012 (P > 0.05) from validation set, and the likelihood ratio test showed P < 0.05.

Conclusion

This study showed that preoperative high NLR (NLR≥3.555) was an independent risk factor associated with postoperative AKI (OR, 2.410; 95% CI, 1.371–4.335) in patients for non-cardiac surgery under general anesthesia.

Intraoperative hypotension is associated with persistent acute kidney disease after noncardiac surgery: a multicentre cohort study

BACKGROUND

Whilst intraoperative hypotension is associated with postoperative acute kidney injury (AKI), the link between intraoperative hypotension and acute kidney disease (AKD), defined as continuing renal dysfunction for up to 3 months after exposure, has not yet been studied.

METHODS

We conducted a retrospective multicentre cohort study using data from noncardiac, non-obstetric surgery extracted from a US electronic health records database. Primary outcome was the association between intraoperative hypotension, at three MAP thresholds (≤75, ≤65, and ≤55 mm Hg), and the following two AKD subtypes: (i) persistent (initial AKI incidence within 7 days of surgery, with continuation between 8 and 90 days post-surgery) and (ii) delayed (renal impairment without AKI within 7 days, with AKI occurring between 8 and 90 days post-surgery). Secondary outcomes included healthcare resource utilisation for patients with either AKD subtype or no AKD.

RESULTS

A total of 112 912 surgeries qualified for the study. We observed a rate of 2.2% for delayed AKD and 0.6% for persistent AKD. Intraoperative hypotension was significantly associated with persistent AKD at MAP ≤55 mm Hg (hazard ratio 1.1; 95% confidence interval: 1.38-1.22; P<0.004). However, IOH was not significantly associated with delayed AKD across any of the MAP thresholds. Patients with delayed or persistent AKD had higher healthcare resource utilisation across both hospital and intensive care admissions, compared with patients with no AKD.

CONCLUSIONS

Intraoperative hypotension is associated with persistent but not delayed acute kidney disease. Both types of acute kidney disease appear to be associated with increased healthcare utilisation. Correction of intraoperative hypotension is a potential opportunity to decrease postoperative kidney injury and associated costs.

Utility of plasma NGAL for the diagnosis of AKI following cardiac surgery requiring cardiopulmonary bypass: a systematic review and meta-analysis

The objective of this study was to assess the diagnostic value of plasma neutrophil gelatinase-associated lipocalin (pNGAL) for the early diagnosis of acute kidney injury (AKI) in adult patients following cardiac surgery requiring cardiopulmonary bypass (CPB). Electronic databases and other resources were systematically searched for relevant studies. Risk of bias was assessed using the Quality Assessment for Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Studies were assigned to a sub-group based on the timing of the pNGAL sample in relation to the cessation of CPB. These were < 4 h, 4–8 h, 12 h or 24 h post-cessation of CPB. Summary values for sensitivity and specificity were estimated using the hierarchical summary receiver operator characteristic (ROC) curve model. A random-effects meta-analysis of each pair of sensitivity and specificity estimates from each included study was performed. In total, 3131 patients from 16 studies were included. When taken at 4–8 h following CPB, pNGAL had superior performance for the diagnosis of AKI in the defined population when compared to earlier and later time points. Prediction regions and confidence intervals, however, demonstrated significant variability in pooled estimates of sensitivity and specificity. This is likely due to population and study design heterogeneity, lack of standardisation of assays and thresholds, and inability to distinguish the different molecular forms of NGAL. In conclusion, the diagnostic utility of pNGAL in this clinical setting is inconclusive and large individual studies of representative populations of cardiac surgery patients using assays that specifically detect NGAL in its monomeric form are required.

Ultrafiltration and cardiopulmonary bypass associated acute kidney injury: A systematic review and meta-analysis

BACKGROUND

Cardiopulmonary bypass is known to raise the risk of acute kidney injury (AKI). Previous studies have identified numerous risk factors of cardiopulmonary bypass including the possible impact of perioperative ultrafiltration. However, the association between ultrafiltration (UF) and AKI remains conflicting. Thus, we conducted a meta-analysis to further examine the relationship between UF and AKI.

HYPOTHESIS

Ultrafiltration during cardiac surgery increases the risk of developping Acute kidney Injury.

METHODS

We searched PubMed, Web of Science, EBSCO, and SCOPUS through July 2021. The RevMan (version 5.4) software was used to calculate the pooled risk ratios (RRs) and mean differences along with their associated confidence intervals (95% CI).

RESULTS

We identified 12 studies with a total of 8005 patients. There was no statistically significant difference in the incidence of AKI between the group who underwent UF and the control group who did not (RR = 0.90, 95% CI = 0.64-1). Subgroup analysis on patients with previous renal insufficiency also yielded nonsignificant difference (RR = 0.84, 95% CI = 0.53 -1.33, p = .47). Subgroup analysis based on volume of ultrafiltrate removed (> or <2900 ml) was not significant and did not increase the AKI risk as predicted (RR = 0.82, 95% CI = 0.63 -1.07, p  = .15). We also did subgroup analysis according to the type of UF and again no significant difference in AKI incidence between UF groups and controls was observed in either the conventional ultrafiltration (CUF), modified ultrafiltration (MUF), zero-balanced ultrafiltration (ZBUF), or combined MUF and CUF subgroups.

CONCLUSION

UF in cardiac surgery is not associated with increased AKI incidence and may be safely used even in baseline chronic injury patients.

The effect of preoperative statin treatment on acute kidney injury in elderly patients undergoing valve replacement surgery

PURPOSES

The effects of preoperative statin treatment on acute kidney injury (AKI) remain controversial, and current clinical evidence regarding statin use in the elderly undergoing valve replacement surgery (VRS) is insufficient. The present study aimed to investigate the association between preoperative statin treatment and AKI after VRS in the elderly.

METHODS

Three thousand seven hundred ninety-one elderly patients (≥ 60 years) undergoing VRS were included in this study and divided into 2 groups, according to the receipt of statin treatment before the operation: statin users (n = 894) and non-users (n = 2897). We determined the associations between statin use, AKI, and other adverse events using a multivariate model and propensity score-matched analysis.

RESULTS

After propensity score-matched analysis, there was no difference between statin users and non-users in regard to postoperative AKI (72.5% vs. 72.4%, p = 0.954), in-hospital death (5.7% vs. 5.1%, p = 0.650) and 1-year mortality (log-rank = 0, p = 0.986). The multivariate analysis showed that statin use was not an independent risk factor for postoperative AKI (OR = 0.97, 95% CI: 0.90-1.17, p = 0.733), in-hospital mortality (OR = 1.12, 95% CI: 0.75-1.68, p = 0.568), or 1-year mortality (HR = 0.95, 95% CI: 0.70-1.28, p = 0.715).

CONCLUSION

Preoperative statin treatment did not significantly affect the risk of AKI among elderly patients undergoing VRS.

Dynamics of Vascular Protective and Immune Supportive Sphingosine-1-Phosphate During Cardiac Surgery

Introduction

Sphingosine-1-phosphate (S1P) is a signaling lipid and crucial in vascular protection and immune response. S1P mediated processes involve regulation of the endothelial barrier, blood pressure and S1P is the only known inducer of lymphocyte migration. Low levels of circulatory S1P correlate with severe systemic inflammatory syndromes such as sepsis and shock states, which are associated with endothelial barrier breakdown and immunosuppression. We investigated whether S1P levels are affected by sterile inflammation induced by cardiac surgery.

Materials and Methods

In this prospective observational study we included 46 cardiac surgery patients, with cardiopulmonary bypass (CPB, n=31) and without CPB (off-pump, n=15). Serum-S1P, S1P-sources and carriers, von-Willebrand factor (vWF), C-reactive protein (CRP), procalcitonin (PCT) and interleukin-6 (IL-6) were measured at baseline, post-surgery and at day 1 (POD 1) and day 4 (POD 4) after surgical stimulus.

Results

Median S1P levels at baseline were 0.77 nmol/mL (IQR 0.61-0.99) and dropped significantly post-surgery. S1P was lowest post-surgery with median levels of 0.37 nmol/mL (IQR 0.31-0.47) after CPB and 0.46 nmol/mL (IQR 0.36-0.51) after off-pump procedures (P<0.001). The decrease of S1P was independent of surgical technique and observed in all individuals. In patients, in which S1P levels did not recover to preoperative baseline ICU stay was longer and postoperative inflammation was more severe. S1P levels are associated with its sources and carriers and vWF, as a more specific endothelial injury marker, in different phases of the postoperative course. Determination of S1P levels during surgery suggested that also the anticoagulative effect of heparin might influence systemic S1P.

Discussion

In summary, serum-S1P levels are disrupted by major cardiac surgery. Low S1P levels post-surgery may play a role as a new marker for severity of cardiac surgery induced inflammation. Due to well-known protective effects of S1P, low S1P levels may further contribute to the observed prolonged ICU stay and worse clinical status. Moreover, we cannot exclude a potential inhibitory effect on circulating S1P levels by heparin anticoagulation during surgery, which would be a new pro-inflammatory pleiotropic effect of high dose heparin in patients undergoing cardiac surgery.

The Effect of Acute Kidney Injury on TGF-β1 and Smad3 in Patients with Coronary Heart Disease after Off-Pump Coronary Artery Bypass Grafting

Background

Acute kidney injury (AKI) is one of the most common and serious complications for coronary disease (CAD) patients, suffering from coronary artery bypass surgery (CABG). AKI occurs in nearly 30% of cardiac surgery patients, including CABG patients, affecting renal function, prolonging hospitalization time, and increasing all-cause mortality. TGF-β1 and Smad3 are sensitive biomarkers in evaluating kidney function. Therefore, comparing the TGF-β1 and Smad3 levels between the AKI patients and non-AKI patients after CABG surgery might have an important significance for identifying the risk degree of AKI and applying effective preventive measures after CABG surgery.

Objective

This study aims at comparing the TGF-β1 and Smad3 levels between the AKI patients and non-AKI patients after CABG surgery to identify the risk degree of AKI and apply effective preventive measures after CABG surgery in clinics.

Materials and Methods

A total of 25 proper patients, diagnosed as coronary disease (CAD) and undergoing AKI after CABG, were selected as the AKI group. The 25 participants, who did not suffer from AKI after CABG, were recruited using the case-control matching method in SPSS 25.0 software as the non-AKI group. Also, corresponding surgical specimens (tissues) and samples of blood were collected from them. Histopathological analysis and immunofluorescent microscopy of lesion artery and kidney of patients, who have been treated with kidney transplants, were performed on surgical specimens to find the pathological and histological change difference between the two groups. RT-PCR and Western blot were conducted to quantify the levels of TGF-β1 and Smad3 expression in serum for the patients of AKI and non-AKI groups, respectively.

Results

Serious renal fibrosis was noted in patients of the AKI group. In addition, by H&E staining of the lesion artery, severe histopathological changes including smooth muscles proliferation with endothelial cell infiltration, focal degeneration and disruptions, and less collagen accumulation were found in the lesion artery of patients from the AKI group. Higher levels of TGF-β1 and Smad3 were observed in serum of patients of the AKI group.

Conclusion

: The increased levels of TGF-β1 and Smad3 in serum might be risk factors for triggering AKI for CAD patients undergoing CABG.

Managing patients of shock and acute kidney injury in tertiary care cardiac ICU: Experience with continuous renal replacement therapy

Background

Clinical experience on details of CRRT initiation and outcomes in cardiac intensive care unit (CICU) patients is not available from developing countries like India. This study shares the 5-year clinical experience of managing CICU patients requiring CRRT in a tertiary care cardiac center of North India.

Materials and methods

Medical records of all CICU patients with acute kidney injury (AKI) managed by CRRT from October 2011 to September 2016 at tertiary referral center in North India were retrospectively reviewed. Multiple logistic regression analysis was used to identify predictors of post-CRRT mortality.

Results

A total of 630 patients received CRRT during the study period. Most commonly AKI developed in patients with acute coronary syndrome (30.2 %) with cardiogenic shock. 55.9 % of the CRRT patients were >60 years of age, and/or on multiple supports in ICU including, mechanical ventilation, high doses of inotropes & vasopressors and other cardiovascular support. Of those on CRRT, 130 (20.6 %) patients had died, 215 (34.1 %) were discharged and 285 (45.2 %) could not complete the desired course. Multivariate regression analysis showed independent association of mortality with high vasoactive-inotropic score, single CRRT cycle and low mean arterial pressure in CRRT patients.

Conclusion

About 34.1 % of patients receiving CRRT were alive at discharge, emphasizing the feasibility and utility of CRRT as a promising modality in this population for improving outcomes.

Additional benefit of induced pluripotent stem cell-derived mesenchymal stem cell therapy on sepsis syndrome-associated acute kidney injury in rat treated with antibiotic

BACKGROUND

This study tested whether human induced-pluripotent stem-cell-derived mesenchymal-stem-cells (iPS-MSCs) would offer an additional benefit to the rodent with acute kidney injury (AKI) (ischemia for 1 h followed by reperfusion for 120 h) associated sepsis syndrome (SS) (by cecal-ligation-puncture immediately after AKI-induction) undergoing ciprofloxacin therapy.

RESULTS

Male-adult SD rats (n = 80) were categorized into group 1 (sham-operated-control, n = 10), group 2 (AKI + SS, n = 24), group 3 (AKI + SS + ciprofloxacin/3 mg/kg, orally for 120 h, n = 12), group 4 (AKI + SS + iPS-MSCs/1.2 × 10⁶/intravenously administered by 3 h after AKI, n = 12), group 5 (AKI + SS + iPS-MSCs/1.2 × 10⁶/intravenously administered by 18 h after AKI, n = 12), group 6 (AKI + SS + iPS-MSCs/1.2 × 10⁶/intravenously administered by 3 h after AKI induction + ciprofloxacin, n = 10] and euthanized by 120 h. The result showed that the mortality was significantly higher in group 2 than in other groups (all p < 0.01). The creatinine level was highest in group 2, lowest in group 1, significantly lower in group 6 than in groups 3, 4 and 5, (all p < 0.0001), but it showed no difference among the latter 3 groups. Flow cytometric analysis showed that the circulatory inflammatory cells (Ly6G/CD11^b/c), early (AN-V+/PI-)/late (AN-V+/PI+) apoptosis, and circulatory/splenic immune cells (CD3+/CD4+, CD3+/CD8a+) were highest in group 2, lowest in group 1, significantly lower in group 6 than in groups 3/4/5 and significantly lower in group 4 than in groups 3/5 (all p < 0.0001), but they showed no difference between groups 3/5. Protein expressions of oxidative-stress (NOX-1/NOX2/oxidized protein), apoptotic (cleaved-caspase3/cleaved-PARP/mitochondrial-Bax), fibrotic (TGF-ß/Smad3), inflammatory (MMP-9/IL-6/TNF-α) and autophagic (Atg5/Beclin) biomarkers in kidney exhibited an identical pattern of circulatory inflammatory cells (all p < 0.0001).

CONCLUSION

Combined iPS-MSCs-ciprofloxacin therapy was superior to either one alone for protecting AKI complicated by SS.

Accuracy of Liver-Type Fatty Acid-Binding Protein in Predicting Acute Kidney Injury: A Meta-Analysis

BACKGROUND

Liver-type fatty acid-binding protein (L-FABP) is a promising biomarker for the early prediction of acute kidney injury (AKI). However, the clinical utility of L-FABP in different populations or settings remains unclear. We present a meta-analysis of studies evaluating the performance of L-FABP in AKI prediction.

METHODS

We performed a literature search in MEDLINE, EMBASE, and Cochrane library, using search terms "acute kidney injury" and "L-FABP." Studies investigating the performance characteristics of L-FABP for the early diagnosis of AKI were included. Data about patient characteristics, diagnostic criteria of AKI, quantitative data required for construction of a 2 × 2 table (number of participants, sensitivity, specificity, and case number), study settings, and outcomes were extracted. The bivariable model was applied to calculate the estimated sensitivity and specificity of L-FABP. A summary ROC curve was created by plotting the true-positive rate against the false-positive rate at various cutoff values from different studies.

RESULTS

We found 27 studies reporting measurement of urine (n = 25 studies) or plasma (n = 2 studies) L-FABP. Overall, the estimated sensitivity was 0.74 (95% CI: 0.69-0.80) and specificity was 0.78 (95% CI: 0.71-0.83). L-FABP demonstrated a stable area under the ROC of 0.82 (95% CI: 0.79-0.85) in variable clinical settings including intensive care unit, surgery, and contrast-induced AKI. In subgroup analysis excluding pediatric and post radiocontrast exposure cohorts, L-FABP had comparative diagnostic performance with neutrophil gelatinase associated lipocalin (NGAL).

CONCLUSIONS

Despite broad prevalence, L-FABP is a clinically useful marker with moderate accuracy in variable clinical settings as demonstrated in our subgroup analysis. Except for pediatric patients and those post-radiocontrast exposure, L-FABP has comparable discriminative capability as NGAL.

Impact of chronic kidney disease in chronic total occlusion management and clinical outcomes

BACKGROUND

Data on the impact of chronic kidney disease (CKD) on clinical outcomes in chronic total occlusion (CTO) patients is scarce, and the optimal treatment strategy for this population is not well established. This study aims to compare differences in CTO management and long-term clinical outcomes, including all-cause and cardiac mortalities, according to baseline glomerular filtration rate (GFR).

METHODS

All patients with at least one CTO diagnosed in our center between 2010 and 2014 were included. Demographic and clinical data were registered. All-cause and cardiac mortalities were assessed during a median follow-up of 4.03 years (IQR 2.6-4.8). Clinical outcomes were compared between patients with CKD (GFR < 60 mL/min/1.73 m²) and without CKD (GFR ≥ 60 mL/min/1.73 m²).

RESULTS

A total of 1248 patients (67.3 ± 10.9 years; 32% CKD) were identified. CKD patients were older and had a higher prevalence of hypertension, type 2 diabetes, peripheral arterial disease, and severe left ventricular dysfunction compared to patients with normal renal function (p < 0.05). Subjects with renal dysfunction were more often treated with MT alone, compared to patients without CKD (63% vs 45%; p < 0.001), who were more likely to undergo PCI or surgery. During follow-up, 386 patients [31%] died. CKD patients had a higher rate of all-cause and cardiac mortalities compared to patients without CKD (p < 0.001). The independent predictors for all-cause mortality were age, GFR < 60 mL/min/1.73 m², Syntax Score I, and successful revascularization of the CTO (CABG or PCI-CTO). Among patients with CKD, advanced age, eGFR <30 mL/min/1.73 m², and CTO successful revascularization were predictors of all-cause mortality.

CONCLUSIONS

Patients with CKD were more often treated with MT alone. At long-term follow-up, revascularization of the CTO is associated with lower all-cause and cardiac mortalities in this population.

Combined tacrolimus and melatonin effectively protected kidney against acute ischemia-reperfusion injury

Acute kidney injury (AKI) is commonly encountered and causes high mortality in hospitalized patients; however, effective therapies for AKI have still not been established. Accordingly, we performed a rodent model with acute renal ischemia-reperfusion (IR) and tested the hypothesis that combined tacrolimus and melatonin therapy could be superior to either one for protecting the kidney against IR injury. Adult-male SD rat (n = 30) were equally categorized into group 1 (receiving laparotomy only), group 2 (IR treated by 3.0 cc/normal-saline), group 3 [IR + tacrolimus/0.5 mg/kg by intravenous administration at 30 minutes and at days 1/2/3 after IR], group 4 (IR + melatonin/50 mg/kg by intra-peritoneal administration at 30 minutes and 25 mg/kg at days 1/2/3 after IR] and group 5 (IR + tacrolimus +melatonin). By day 3 after IR, the creatinine/BUN levels and ratio of urine protein to urine creatinine were highest in group 2, lowest in group 1 and significantly lower in group 5 than in groups 3/4 (all P < .0001), but they did not differ between the groups 3/4. The protein expressions of oxidative-stress (p47phox/NOX-1/NOX-2/NOX-4), upstream (TLR4/MAL/MyD88/TRAF6/ASK1/MKK4/MKK7/NF-κB) and downstream (IL-6/INF-γ/MMP-9/IL-1ß) inflammatory signaling, MAPK-family-signaling cascades(ERK1/2, JNK/p38/c-JUN), apoptotic/autophagic (p53/caspase 3/mitochondrial-Bax, ratio of LC3B-II/LC3B-I), and mitochondrial-damaged (cyclophilin D/cytochrome C/DRP1) biomarkers, and the expressions of inflammatory-immune cells (F4/80, CD14/CD3/CD8) as well as the kidney injured score exhibited an identical pattern of creatinine level (all P < .0001). In conclusion, combined tacrolimus and melatonin therapy was better than either single one on protecting the kidney functional and anatomical integrity against IR injury through suppressing inflammation and the generation of oxidative stress.

The Association of Matrix Metalloproteinases With Acute Kidney Injury Following CPB-Supported Cardiac Surgery

BACKGROUND

Cardiac surgery-associated acute kidney injury (AKI) is an adverse outcome that increases morbidity and mortality in patients undergoing cardiac surgical procedures. To date, the use of serum creatinine levels as an early indicator of AKI has limitations because of its slow rise and poor predictive accuracy for renal injury. This delay in diagnosis may lead to prolonged initiation in treatment and increased risk for adverse outcomes.

OBJECTIVE

This pilot study explores serum and urine matrix metalloproteinases (MMPs)-2 and MMP-9 and their association, and potentially earlier detection of AKI in patients following cardiopulmonary bypass (CPB)-supported cardiac surgery. We hypothesize that increased activity of serum and urine levels MMP-2 and/ or MMP-9 are associated with AKI. Furthermore, MMP-2 and/ or MMP-9 may provide earlier identification of AKI as compared with serum levels of creatinine.

METHODS

During the study period, there were 150 CPB-supported surgeries, 21 of which developed AKI according to the Kidney Disease Improving Global Outcomes criteria. We then selected a sample of 21 matched cases from those patients who went through the surgery without developing AKI. Primary outcomes were the measurement via gel zymography of the serum and urine activity of MMP-2 and MMP-9 drawn at the following intervals: pre-CPB; 10-minute post-CPB; and 4-hour post-CPB time points. Secondary variables were the measurement of serum creatinine, intensive care unit (ICU) fluid balance, and length of ICU stay.

RESULTS

At the 10-minute and 4-hour post-CPB time points, the serum MMP-2 activity of AKI patients were significantly higher as compared with non-AKI patients (P < .001 and P = .004), respectively. Similarly, at the 10-minute and 4-hour post-CPB time points, the serum MMP-9 activity of AKI patients was significantly higher as compared with non-AKI patients (P = .001 and P = .014), respectively. The activity of urine MMP-2 and MMP-9 of AKI patients was significantly higher as compared with non-AKI patients at all 3 time points (P = .004, P < .001, P < .001), respectively.

CONCLUSION

Although the pilot study may have limitations, it has demonstrated that the serum and urine levels of activity of MMP-2 and MMP-9 are associated with the clinical endpoint of AKI and appear to have earlier rising levels as compared with those of serum creatinine. Furthermore, in depth, exploration is underway with a larger sample size to attempt validation of the analytical performance and reproducibility of the assay for MMP-2 and MMP-9 to aid in earlier diagnosis of AKI following CPB-supported cardiac surgery.

Blood Transfusion and Acute Kidney Injury After Total Aortic Arch Replacement for Acute Stanford Type A Aortic Dissection

AIM

To evaluate the effect of packed red blood cells (pRBCs), fresh frozen plasma (FFP), and platelet concentrate (PC) transfusions on acute kidney injury (AKI) in patients with acute Stanford type A aortic dissection (ATAAD) with total arch replacement (TAR).

METHOD

From December 2015 to October 2017, 421 consecutive patients with ATAAD undergoing TAR were included in the study. The clinical data of the patients and the amount of pRBCs, FFP, and PC were collected. Acute kidney injury was defined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Logistic regression was used to identify whether pRBCs, FFP, and platelet transfusions were risk factors for KDIGO AKI, stage 3 AKI, and AKI requiring renal replacement therapy (RRT).

RESULTS

The mean ± standard deviation age of the patients was 47.67±10.82 years; 77.7% were men; and the median time from aortic dissection onset to operation was 1 day (range, 0-2 days). The median transfusion amount was 8 units (range, 4-14 units) for pRBCs, 400 mL (range, 0-800 mL) for FFP, and no units (range, 0-2 units) for PC. Forty-one (41; 9.7%) patients did not receive any blood products. The rates of pRBC, PC, and FFP transfusions were 86.9%, 49.2%, and 72.9%, respectively. The incidence of AKI was 54.2%. Considering AKI as the endpoint, multivariate logistic regression showed that pRBCs (odds ratio [OR], 1.11; p<0.001) and PC transfusions (OR, 1.28; p=0.007) were independent risk factors. Considering KDIGO stage 3 AKI as the endpoint, multivariate logistic regression showed that pRBC transfusion (OR, 1.15; p<0.001), PC transfusion (OR, 1.28; p<0.001), a duration of cardiopulmonary bypass (CPB) ≥293 minutes (OR, 2.95; p=0.04), and a creatinine clearance rate of ≤85 mL/minute (OR, 2.12; p=0.01) were independent risk factors. Considering RRT as the endpoint, multivariate logistic regression showed that pRBC transfusion (OR, 1.12; p<0.001), PC transfusion (OR, 1.33; p=0.001), a duration of CPB ≥293 minutes (OR, 3.79; p=0.02), and a creatinine clearance rate of ≤85 mL/minute (OR, 3.34; p<0.001) were independent risk factors.

CONCLUSIONS

Kidney Disease: Improving Global Outcomes-defined stage AKI was common after TAR for ATAAD. Transfusions of pRBCs and PC increased the incidence of AKI, stage 3 AKI, and RRT. Fresh frozen plasma transfusion was not a risk factor for AKI.