Cardiac and Vascular Surgery-Associated Acute Kidney Injury: The 20th International Consensus Conference of the ADQI (Acute Disease Quality Initiative) Group

Cardiopulmonary bypass associated acute kidney injury: better understanding and better prevention

Cardiopulmonary bypass (CPB) is a common technique in cardiac surgery but is associated with acute kidney injury (AKI), which carries considerable morbidity and mortality. In this review, we explore the range and definition of CPB-associated AKI and discuss the possible impact of different disease recognition methods on research outcomes. Furthermore, we introduce the specialized equipment and procedural intricacies associated with CPB surgeries. Based on recent research, we discuss the potential pathogenesis of AKI that may result from CPB, including compromised perfusion and oxygenation, inflammatory activation, oxidative stress, coagulopathy, hemolysis, and endothelial damage. Finally, we explore current interventions aimed at preventing and attenuating renal impairment related to CPB, and presenting these measures from three perspectives: (1) avoiding CPB to eliminate the fundamental impact on renal function; (2) optimizing CPB by adjusting equipment parameters, optimizing surgical procedures, or using improved materials to mitigate kidney damage; (3) employing pharmacological or interventional measures targeting pathogenic factors.

AKI-Pro score for predicting progression to severe acute kidney injury or death in patients with early acute kidney injury after cardiac surgery

BACKGROUND

No reliable clinical tools exist to predict acute kidney injury (AKI) progression. We aim to explore a scoring system for predicting the composite outcome of progression to severe AKI or death within seven days among early AKI patients after cardiac surgery.

METHODS

In this study, we used two independent cohorts, and patients who experienced mild/moderate AKI within 48 h after cardiac surgery were enrolled. Eventually, 3188 patients from the MIMIC-IV database were used as the derivation cohort, while 499 patients from the Zhongshan cohort were used as external validation. The primary outcome was defined by the composite outcome of progression to severe AKI or death within seven days after enrollment. The variables identified by LASSO regression analysis were entered into logistic regression models and were used to construct the risk score.

RESULTS

The composite outcome accounted for 3.7% (n = 119) and 7.6% (n = 38) of the derivation and validation cohorts, respectively. Six predictors were assembled into a risk score (AKI-Pro score), including female, baseline eGFR, aortic surgery, modified furosemide responsiveness index (mFRI), SOFA, and AKI stage. And we stratified the risk score into four groups: low, moderate, high, and very high risk. The risk score displayed satisfied predictive discrimination and calibration in the derivation and validation cohort. The AKI-Pro score discriminated the composite outcome better than CRATE score, Cleveland score, AKICS score, Simplified renal index, and SRI risk score (all P < 0.05).

CONCLUSIONS

The AKI-Pro score is a new clinical tool that could assist clinicians to identify early AKI patients at high risk for AKI progression or death.

A Randomized Trial of Intravenous Amino Acids for Kidney Protection

BACKGROUND

Acute kidney injury (AKI) is a serious and common complication of cardiac surgery, for which reduced kidney perfusion is a key contributing factor. Intravenous amino acids increase kidney perfusion and recruit renal functional reserve. However, the efficacy of amino acids in reducing the occurrence of AKI after cardiac surgery is uncertain.

METHODS

In a multinational, double-blind trial, we randomly assigned adult patients who were scheduled to undergo cardiac surgery with cardiopulmonary bypass to receive an intravenous infusion of either a balanced mixture of amino acids, at a dose of 2 g per kilogram of ideal body weight per day, or placebo (Ringer's solution) for up to 3 days. The primary outcome was the occurrence of AKI, defined according to the Kidney Disease: Improving Global Outcomes creatinine criteria. Secondary outcomes included the severity of AKI, the use and duration of kidney-replacement therapy, and all-cause 30-day mortality.

RESULTS

We recruited 3511 patients at 22 centers in three countries and assigned 1759 patients to the amino acid group and 1752 to the placebo group. AKI occurred in 474 patients (26.9%) in the amino acid group and in 555 (31.7%) in the placebo group (relative risk, 0.85; 95% confidence interval [CI], 0.77 to 0.94; P = 0.002). Stage 3 AKI occurred in 29 patients (1.6%) and 52 patients (3.0%), respectively (relative risk, 0.56; 95% CI, 0.35 to 0.87). Kidney-replacement therapy was used in 24 patients (1.4%) in the amino acid group and in 33 patients (1.9%) in the placebo group. There were no substantial differences between the two groups in other secondary outcomes or in adverse events.

CONCLUSIONS

Among adult patients undergoing cardiac surgery, infusion of amino acids reduced the occurrence of AKI. (Funded by the Italian Ministry of Health; PROTECTION ClinicalTrials.gov number, NCT03709264.).

The effectiveness of dexmedetomidine for preventing acute kidney injury after surgery: a systematic review and meta-analysis

Background

Postoperative acute kidney injury (AKI) is a serious and distressing complication connected to various adverse outcomes following the surgical operation. Controversy remains regarding the dexmedetomidine's preventive impact on postoperative AKI. Therefore, this investigation aims to explore the efficiency and safety of dexmedetomidine in preventing AKI after surgical operation.

Methods

We systematically searched electronic databases such as PubMed, Embase, Web of Science, and the Cochrane Library to detect eligible randomized controlled studies that used dexmedetomidine for the prevention of AKI following operation up to April 30, 2023. The main outcome evaluated was AKI incidence. The evidence quality was assessed employing the Grading of Recommendations Assessment, Development, and Evaluation.

Results

The meta-analysis included 25 trials, including 3,997 individuals. Of these, 2,028 were in the dexmedetomidine group, and 1,969 were in the control group. The result showed that patients administered dexmedetomidine significantly decreased the AKI incidence following surgical operation in contrast to the control group (risk ratio, 0.60; 95% confidence intervals, 0.45-0.78; p < 0.05; I 2 = 46%). In addition, dexmedetomidine decreased the period of hospitalization in both the intensive care unit (ICU) and the hospital while also reducing postoperative delirium (POD) occurrence. However, dexmedetomidine elevated the incidence of bradycardia but did not have a significant impact on other indicators.

Conclusion

Our meta-analysis indicates that the dexmedetomidine treatment reduces the postoperative AKI and POD risk while also shortening the time of hospitalization in the ICU and hospital. However, it is connected to an increased bradycardia risk.

Determinants of postoperative complications in high-risk noncardiac surgery patients optimized with hemodynamic treatment strategies: A post-hoc analysis of a randomized multicenter clinical trial

STUDY OBJECTIVE

This post-hoc analysis of a randomized controlled trial was undertaken to establish the determinants of postoperative complications and acute kidney injury in high-risk noncardiac surgery patients supported with hemodynamic treatment strategies.

DESIGN

We conducted a post-hoc analysis of patients enrolled in the OPtimization Hemodynamic Individualized by the respiratory QUotiEnt (OPHIQUE) trial.

SETTING

Operating rooms in four university medical centers and one non-university hospital from December 26, 2018, to September 9, 2021.

PATIENTS

We enrolled 350 patients with a high risk of postoperative complications undergoing high-risk noncardiac surgery lasting 2 h or longer under general anesthesia.

INTERVENTIONS

All patients were treated according to hemodynamic treatment strategies which included cardiac output optimization by titration of fluid challenge and targeted systolic blood pressure to remain within ±10% of the reference value.

MEASUREMENTS

We assessed the association between pre-operative and intra-operative exposure of interest with a composite primary outcome of major complications or death within seven days following surgery using a multivariable logistic regression model. We also assessed the association between these exposures of interest and acute kidney injury.

MAIN RESULTS

The data of 341 patients were analyzed. In multivariate analysis, the factors independently associated with the primary outcome were age (OR = 1.04 (1.01-1.06), P = 0.002), preoperative hemoglobin concentration (OR = 0.85 (0.75-0.96), P = 0.012), non-vascular surgery (OR = 0.30 (0.17-0.53), P < 0.0001), and intraoperative surgical complications (OR = 2.08 (1.02-4.24), P = 0.046). The factors independently associated with postoperative acute kidney injury were age (OR = 1.04 (1.01-1.08), P = 0.008), preoperative creatinine concentration (OR = 1.01 (1.00-1.01), P = 0.049), non-vascular surgery (OR = 0.36 (0.20-0.66), P = 0.001), and intraoperative surgical complications (OR = 3.36 (1.50-7.55), P = 0.031).

CONCLUSIONS

Surgical complications, a lower preoperative hemoglobin concentration, age, and vascular surgery were associated with postoperative complications in a high-risk noncardiac surgery population supported with hemodynamic treatment strategies.

Albumin: a comprehensive review and practical guideline for clinical use

PURPOSE

Nowadays, it is largely accepted that albumin should not be used in hypoalbuminemia or for nutritional purpose. The most discussed indication of albumin at present is the resuscitation in shock states, especially distributive shocks such as septic shock. The main evidence-based indication is also liver disease. In this review, we provided updated evidence-based instruction for definite and potential indications of albumin administration in clinical practice, with appropriate dosing and duration.

METHODS

Data collection was carried out until November 2023 by search of electronic databases including PubMed, Google Scholar, Scopus, and Web of Science. GRADE system has been used to determine the quality of evidence and strength of recommendations for each albumin indication.

RESULTS

A total of 165 relevant studies were included in this review. Fluid replacement in plasmapheresis and liver diseases, including hepatorenal syndrome, spontaneous bacterial peritonitis, and large-volume paracentesis, have a moderate to high quality of evidence and a strong recommendation for administering albumin. Moreover, albumin is used as a second-line and adjunctive to crystalloids for fluid resuscitation in hypovolemic shock, sepsis and septic shock, severe burns, toxic epidermal necrolysis, intradialytic hypotension, ovarian hyperstimulation syndrome, major surgery, non-traumatic brain injury, extracorporeal membrane oxygenation, acute respiratory distress syndrome, and severe and refractory edema with hypoalbuminemia has a low to moderate quality of evidence and weak recommendation to use. Also, in modest volume paracentesis, severe hyponatremia in cirrhosis has a low to moderate quality of evidence and a weak recommendation.

CONCLUSION

Albumin administration is most indicated in management of cirrhosis complications. Fluid resuscitation or treatment of severe and refractory edema, especially in patients with hypoalbuminemia and not responding to other treatments, is another rational use for albumin. Implementation of evidence-based guidelines in hospitals can be an effective measure to reduce inappropriate uses of albumin.

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.

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.

Plasma hyperosmolality during cardiopulmonary bypass is a risk factor for postoperative acute kidney injury: Results from double blind randomised controlled trial

INTRODUCTION

The study objective was to investigate whether a Ringer's acetate based priming solution with addition of Mannitol and sodium concentrate increases the risk of cardiac surgery associated kidney injury (CSA-AKI).

METHODS

This is a double blind, prospective randomized controlled trial from a single tertiary teaching hospital in Sweden including patients aged ≥65 years (n = 195) admitted for routine cardiac surgery with cardiopulmonary bypass. Patients in the study group received Ringer's acetate 1000 mL + 400 mL Mannitol (60 g) + sodium chloride 40 mL (160 mmol) and heparin 2 mL (10 000 IU) 966 mOsmol (n = 98), while patients in the control group received Ringer's acetate 1400 mL + heparin 2 mL (10 000 IU), 388 mOsmol (n = 97) as pump prime. Acute kidney injury was analysed based on the Kidney Disease Improving Outcomes (KDIGO 1-3) definition.

RESULTS

The overall incidence of CSA-AKI (KDIGO stage 1) was 2.6% on day 1 in the ICU and 5.6% on day 3, postoperatively. The serum creatinine level did not show any postoperative intergroup differences, when compared to baseline preoperative values. Six patients in the Ringer and five patients in the Mannitol group developed CSA-AKI (KDIGO 1-3), all with glomerular filtration rates <60 mL/min/1.73 m2. These patients showed significantly higher plasma osmolality levels compared to preoperative values. Hyperosmolality together with patient age and the duration of the surgery were independent risk factors for postoperative acute kidney injury (KDIGO 1-3).

CONCLUSIONS

The use of a hyperosmolar prime solution did not increase the incidence of postoperative CSA-AKI in this study, while high plasma osmolality alone increased the associated risk by 30%. The data suggests further examination of plasma hyperosmolality as a relative risk factor of CSA-AKI.

Population Pharmacokinetics of Caffeine in Neonates with Congenital Heart Disease and Associations with Acute Kidney Injury

Cardiac surgery-associated acute kidney injury (CS-AKI) occurs in approximately 65% of neonates undergoing cardiac surgery on cardiopulmonary bypass and contributes to morbidity and mortality. Caffeine may reduce CS-AKI by counteracting adenosine receptor upregulation after bypass, but pharmacokinetics (PK) in this population are unknown. The goal of our analysis is to address knowledge gaps in age-, disease-, and bypass-related effects on caffeine disposition and explore preliminary associations between caffeine exposure and CS-AKI using population PK modeling techniques and an opportunistic, electronic health record-integrated trial design. We prospectively enrolled neonates receiving preoperative caffeine per standard of care and collected PK samples. We retrospectively identified neonates without caffeine exposure undergoing surgery on bypass as a control cohort. We followed US Food and Drug Administration guidance for population PK model development using NONMEM. Effects of clinical covariates on PK parameters were evaluated. We simulated perioperative exposures and used multivariable logistic regression to evaluate the association between caffeine exposure and CS-AKI. Twenty-seven neonates were included in model development. A 1-compartment model with bypass time as a covariate on clearance and volume of distribution best fit the data. Twenty-three neonates with caffeine exposure and 109 controls were included in the exposure-response analysis. Over half of neonates developed CS-AKI. On multivariable analysis, there were no significant differences between CS-AKI with and without caffeine exposure. Neonates with single-ventricle heart disease without CS-AKI had consistently higher simulated caffeine exposures. Our results highlight areas for further study to better understand disease- and bypass-specific effects on drug disposition and identify populations where caffeine may be beneficial.

Intraoperative and Postoperative Hemodynamic Predictors of Acute Kidney Injury in Pediatric Heart Transplant Recipients

Acute kidney injury (AKI) is common after pediatric heart transplantation (HT) and is associated with inferior patient outcomes. Hemodynamic risk factors for pediatric heart transplant recipients who experience AKI are not well described. We performed a retrospective review of 99 pediatric heart transplant patients at Lucile Packard Children's Hospital Stanford from January 1, 2015, to December 31, 2019, in which clinical and demographic characteristics, intraoperative perfusion data, and hemodynamic measurements in the first 48 postoperative hours were analyzed as risk factors for severe AKI (Kidney Disease: Improving Global Outcomes [KDIGO] stage ≥ 2). Univariate analysis was conducted using Fisher's exact test, Chi-square test, and the Wilcoxon rank-sum test, as appropriate. Multivariable analysis was conducted using logistic regression. Thirty-five patients (35%) experienced severe AKI which was associated with lower intraoperative cardiac index ( p  = 0.001), higher hematocrit ( p  < 0.001), lower body temperature ( p  < 0.001), lower renal near-infrared spectroscopy ( p  = 0.001), lower postoperative mean arterial blood pressure (MAP: p  = 0.001), and higher central venous pressure (CVP; p  < 0.001). In multivariable analysis, postoperative CVP >12 mm Hg (odds ratio [OR] = 4.27; 95% confidence interval [CI]: 1.48-12.3, p  = 0.007) and MAP <65 mm Hg (OR = 4.9; 95% CI: 1.07-22.5, p  = 0.04) were associated with early severe AKI. Children with severe AKI experienced longer ventilator, intensive care, and posttransplant hospital days and inferior survival ( p  = 0.01). Lower MAP and higher CVP are associated with severe AKI in pediatric HT recipients. Patients, who experienced AKI, experienced increased intensive care unit (ICU) morbidity and inferior survival. These data may guide the development of perioperative renal protective management strategies to reduce AKI incidence and improve patient outcomes.

Improved early risk stratification of deep sternal wound infection risk after coronary artery bypass grafting

BACKGROUND

Deep sternal wound infection (DSWI) following open heart surgery is associated with excessive morbidity and mortality. Contemporary DSWI risk prediction models aim at identifying high-risk patients with varying complexity and performance characteristics. We aimed to optimize the DSWI risk factor set and to identify additional risk factors for early postoperative detection of patients prone to DSWI.

METHODS

Single-centre retrospective analysis of patients with isolated multivessel coronary artery disease undergoing myocardial revascularization at Paracelsus Medical University Nuremberg between 2007 and 2022 was performed to identify risk factors for DSWI. Three data sets were created to examine preoperative, intraoperative, and early postoperative parameters, constituting the "Baseline", the "Improved Baseline" and the "Extended" models. The "Extended" data set included risk factors that had not been analysed before. Univariable and stepwise forward multiple logistic regression analyses were performed for each respective set of variables.

RESULTS

From 5221 patients, 179 (3.4%) developed DSWI. The "Extended" model performed best, with the area under the curve (AUC) of 0.80, 95%-CI: [0.76, 0.83]. Pleural effusion requiring intervention, postoperative delirium, preoperative hospital stay > 24 h, and the use of fibrin sealant were new independent predictors of DSWI in addition to age, Diabetes Mellitus on insulin, Body Mass Index, peripheral artery disease, mediastinal re-exploration, bilateral internal mammary harvesting, acute kidney injury and blood transfusions.

CONCLUSIONS

The "Extended" regression model with the short-term postoperative complications significantly improved DSWI risk discrimination after surgical revascularization. Short preoperative stay, prevention of postoperative delirium, protocols reducing the need for evacuation of effusion and restrictive use of fibrin sealant for sternal closure facilitate DSWI reduction.

TRIAL REGISTRATION

The registered retrospective study was registered at the study centre and approved by the Institutional Review Board of Paracelsus Medical University Nuremberg (IRB-2019-005).

Meaning and Management of Perioperative Oliguria

Perioperative oliguria is an alarm signal. The initial assessment includes closer patient monitoring, evaluation of volemic status, risk-benefit of fluid challenge or furosemide stress test, and investigation of possible perioperative complications.

Effect of preoperative moderate-dose statin and duration on acute kidney injury after cardiac surgery: a retrospective cohort study

BACKGROUND

The impact of preoperative statin use on postoperative acute kidney injury (AKI) is uncertain. We aimed to examine the association of statin therapy before cardiac surgery with postoperative AKI.

METHODS

The retrospective cohort study consisted of 1581 patients undergoing cardiac surgery. Postoperative AKI were identified by the modified KDIGO definition. Propensity-score matching was employed to control for selection bias, and logistic regression was used to control for confounders. Subgroup and interaction analyses were performed to evaluate the robustness of the findings.

RESULTS

The overall incidence of postoperative AKI and severe AKI were 42.19% and 12.27%, respectively. Preoperative moderate-dose statin was significantly associated with a reduced incidence of postoperative AKI (28.9% vs 43.0%, OR (95%CI): 0.54 (0.38, 0.77), p < 0.001) and severe AKI (6.9% vs 13.7%, OR (95%CI): 0.46 (0.26, 0.83), p = 0.009). The beneficial effect on postoperative AKI persisted after adjusting for major confounding factors (OR (95%CI): 0.47 (0.34, 0.66)). Decreased risk of postoperative AKI was observed in patients with preoperative statin duration of 7 ∼ 14 days (OR (95%CI): 0.41 (0.25, 0.65)) and over 14 days (OR (95%CI): 0.43 (0.28, 0.65)), but not in those with preoperative statin duration of <7 days. Similar favorable effects were noted in most subgroup patients, except for those with high-risk factors such as diabetes mellitus, previous congestive cardiac failure, arrhythmia, preoperative ACEI/ARB, aortic cross-clamping or IABP.

CONCLUSION

Preoperative moderate-dose statin was significantly related to a decreased risk of postoperative AKI, especially in patients who received statins for a longer duration. Further large-scale multicenter randomized controlled trials are needed to ascertain the impact of statin dose, duration, and timing on postoperative AKI in cardiac surgery patients.

Protein Kinase N1 Level Predicts Acute Kidney Injury in Patients Undergoing Cardiac Surgery: A Prospective Cohort Study

INTRODUCTION

The objective of this study was to examine the utility of protein kinase N1 (PKN1) as a biomarker of cardiac surgery-associated AKI (CSA-AKI).

METHODS

A prospective cohort study of 110 adults undergoing on-pump cardiac surgery was conducted. The associations between post-operative PKN1 and CSA-AKI, AKI severity, need for renal replacement therapy (RRT), duration of AKI, length of ICU stay, and post-operative hospital stay were evaluated.

RESULTS

Patients were categorized into three groups according to PKN1 tertiles. The incidence of CSA-AKI in the third tertile was 3.4-fold higher than that in the first. PKN1 was an independent risk factor for CSA-AKI. The discrimination of PKN1 to CSA-AKI assessed by ROC curve indicated that the AUC was 0.70, and the best cutoff was 5.025 ng/mL. This group (>5.025 ng/mL) was more likely to develop CSA-AKI (p < 0.001). The combined AUC of EuroSCORE, aortic cross-clamp time, and PKN1 was 0.82 (p < 0.001). A higher level of PKN1 was related to increased need for RRT, longer duration of AKI, and length of ICU and post-operative hospital stays.

CONCLUSIONS

PKN1 could be a potential biomarker for the prediction of CSA-AKI. The combination of PKN1, EuroSCORE, and aortic cross-clamp time was likely to predict the occurrence of CSA-AKI.

Perioperative Glycemic Management in Cardiac Surgery: A Narrative Review

Diabetes and hyperglycemic events in cardiac surgical patients are associated with postoperative morbidity and mortality. The causes of dysglycemia, the abnormal fluctuations in blood glucose concentrations, in the perioperative period include surgical stress, surgical techniques, medications administered perioperatively, and patient factors. Both hyperglycemia and hypoglycemia lead to poor outcomes after cardiac surgery. While trying to control blood glucose concentration tightly for better postoperative outcomes, hypoglycemia is the main adverse event. Currently, there is no definite consensus on the optimum perioperative blood glucose concentration to be maintained in cardiac surgical patients. This review provides an overview of perioperative glucose homeostasis, the pathophysiology of dysglycemia, factors that affect glycemic control in cardiac surgery, and current practices for glycemic control in cardiac surgery.

The Association Between Serum Glutathione Peroxidase-3 Concentration and Risk of Acute Kidney Injury After Cardiac Surgery: A Nested Case-Control Study

Oxidative stress has an integral role in the pathophysiology of cardiac surgery-associated acute kidney injury (CSA-AKI). Glutathione peroxidase 3 (GPx3) is an important antioxidant enzyme in circulation and is mainly secreted by the kidney. This study aimed to evaluate the relation between GPx3 protein and CSA-AKI. This study is a nested case-control study in Zhongshan Hospital affiliated with Fudan University. We examined serum samples from 80 CSA-AKI patients and 80 age- and gender-matched non-AKI patients who underwent cardiac surgery. AKI was defined according to Kidney Disease: Improving Global Outcomes (KDIGO) 2012 criteria. We measured serum GPx3 concentration using the enzyme-linked immunosorbent assay. GPx3 ratio is the ratio of preoperative and 6 hours postoperative of GPx3 protein concentration. We applied dose-response relation analyses to odds ratio in different GPx3 ratio levels and integrated it into the logistic model to predict the risk of AKI. The receiver operating characteristic curve and area under the curve (AUC) was used to assess the prediction models. Postoperative serum GPx3 concentrations were significantly lower in the AKI group compared with the non-AKI group (1.78 ± 0.33 vs 2.03 ± 0.27, p <0.001). Malondialdehyde was higher in the AKI than in the non-AKI group (17.74 ± 8.65 vs 7.48 ± 4.59, p <0.001). The AKI risk increased in a dose-dependent manner, which was flat in the first half of the GPx3 ratio and then tended to be faster. The peaking odds ratio of CSA-AKI was 2.615 at the GPx3 ratio of 1.21 to 1.40. The AUC value to predict CSA-AKI only included the GPx3 ratio was 72.3%. After gradually integrating other covariates (body mass index, aortic crossclamp time, and cardiopulmonary bypass), the model showed an AUC of 82.6%. The serum GPx3 concentration was significantly lower in the CSA-AKI group. GPx3 ratio has a good predictive value for CSA-AKI, which may be a potential early diagnostic marker for AKI.

Machine learning for dynamic and early prediction of acute kidney injury after cardiac surgery

OBJECTIVE

Acute kidney injury after cardiac surgery increases morbidity and mortality. Diagnosis relies on oliguria or increased serum creatinine, which develop 48 to 72 hours after injury. We hypothesized machine learning incorporating preoperative, operative, and intensive care unit data could dynamically predict acute kidney injury before conventional identification.

METHODS

Cardiac surgery patients at a tertiary hospital (2008-2019) were identified using electronic medical records in the Medical Information Mart for Intensive Care IV database. Preoperative and intraoperative parameters included demographics, Charlson Comorbidity subcategories, and operative details. Intensive care unit data included hemodynamics, medications, fluid intake/output, and laboratory results. Kidney Disease: Improving Global Outcomes creatinine criteria were used for acute kidney injury diagnosis. An ensemble machine learning model was trained for hourly predictions of future acute kidney injury within 48 hours. Performance was evaluated by area under the receiver operating characteristic curve and balanced accuracy.

RESULTS

Within the cohort (n = 4267), there were approximately 7 million data points. Median baseline creatinine was 1.0 g/dL (interquartile range, 0.8-1.2), with 17% (735/4267) of patients having chronic kidney disease. Postoperative stage 1 acute kidney injury occurred in 50% (2129/4267), stage 2 occurred in 8% (324/4267), and stage 3 occurred in 4% (183/4267). For hourly prediction of any acute kidney injury over the next 48 hours, area under the receiver operating characteristic curve was 0.82, and balanced accuracy was 75%. For hourly prediction of stage 2 or greater acute kidney injury over the next 48 hours, area under the receiver operating characteristic curve was 0.95 and balanced accuracy was 86%. The model predicted acute kidney injury before clinical detection in 89% of cases.

CONCLUSIONS

Ensemble machine learning models using electronic medical records data can dynamically predict acute kidney injury risk after cardiac surgery. Continuous postoperative risk assessment could facilitate interventions to limit or prevent renal injury.

Acute renal injury after aortic arch reconstruction with cardiopulmonary bypass for children: prediction models by machine learning of a retrospective cohort study

BACKGROUND

Acute renal injury (AKI) after aortic arch reconstruction with cardiopulmonary bypass leads to injury of multiple organs and increases perioperative mortality. The study was performed to explore risk factors for AKI. We aim to develop a prediction model that can be used to accurately predict AKI through machine learning (ML).

METHODS

A retrospective analysis was performed on 134 patients with aortic arch reconstruction with cardiopulmonary bypass who were treated at our hospital from January 2002 to January 2022. Risk factors for AKI were compositive and were evaluated with comprehensive analyses. Six artificial intelligence (AI) models were used for machine learning to build prediction models and to screen out the best model to predict AKI.

RESULTS

Weight, eGFR, cyanosis, PDA, newborn birth and duration of renal ischemia were closely related to AKI. By integrating the results of the training cohort and validation cohort, we finally confirmed that the logistic regression model was the most stable model among all the models, and the logistic regression model showed good discrimination, calibration and clinical practicability. Based on 6 independent factors, the dynamic nomogram can be used as a predictive tool for clinical application.

CONCLUSIONS

DHCA could be considered in aortic arch reconstruction if additional perfusion of lower body were not performed especially when renal ischemia is greater than 30 min. Machine Learning models should be developed for early recognition of AKI.

TRIAL REGISTRATION

ChiCTR, ChiCTR2200060552. Registered 4 june 2022.

Interpretable machine learning models for early prediction of acute kidney injury after cardiac surgery

OBJECTIVE

Postoperative acute kidney injury (PO-AKI) is a common complication after cardiac surgery. We aimed to evaluate whether machine learning algorithms could significantly improve the risk prediction of PO-AKI.

METHODS

The retrospective cohort study included 2310 adult patients undergoing cardiac surgery in a tertiary teaching hospital, China. Postoperative AKI and severe AKI were identified by the modified KDIGO definition. The sample was randomly divided into a derivation set and a validation set based on a ratio of 4:1. Exploiting conventional logistic regression (LR) and five ML algorithms including decision tree, random forest, gradient boosting classifier (GBC), Gaussian Naive Bayes and multilayer perceptron, we developed and validated the prediction models of PO-AKI. We implemented the interpretation of models using SHapley Additive exPlanation (SHAP) analysis.

RESULTS

Postoperative AKI and severe AKI occurred in 1020 (44.2%) and 286 (12.4%) patients, respectively. Compared with the five ML models, LR model for PO-AKI exhibited the largest AUC (0.812, 95%CI: 0.756, 0.860, all P < 0.05), sensitivity (0.774, 95%CI: 0.719, 0.813), accuracy (0.753, 95%CI: 0.719, 0.781) and Youden index (0.513, 95%CI: 0.451, 0.573). Regarding severe AKI, GBC algorithm showed a significantly higher AUC than the other four ML models (all P < 0.05). Although no significant difference (P = 0.173) was observed in AUCs between GBC (0.86, 95%CI: 0.808, 0.902) and conventional logistic regression (0.803, 95%CI: 0.746, 0.852), GBC achieved greater sensitivity, accuracy and Youden index than conventional LR. Notably, SHAP analyses showed that preoperative serum creatinine, hyperlipidemia, lipid-lowering agents and assisted ventilation time were consistently among the top five important predictors for both postoperative AKI and severe AKI.

CONCLUSION

Logistic regression and GBC algorithm demonstrated moderate to good discrimination and superior performance in predicting PO-AKI and severe AKI, respectively. Interpretation of the models identified the key contributors to the predictions, which could potentially inform clinical interventions.

Cardiac surgery-Associated acute kidney injury - A narrative review

Cardiac Surgery-Associated Acute Kidney Injury (CSA-AKI) is a serious complication seen in approximately 20-30% of cardiac surgery patients. The underlying pathophysiology is complex, often involving both patient- and procedure related risk factors. In contrast to AKI occurring after other types of major surgery, the use of cardiopulmonary bypass comprises both additional advantages and challenges, including non-pulsatile flow, targeted blood flow and pressure as well as the ability to manipulate central venous pressure (congestion). With an increasing focus on the impact of CSA-AKI on both short and long-term mortality, early identification and management of high-risk patients for CSA-AKI has evolved. The present narrative review gives an up-to-date summary on definition, diagnosis, underlying pathophysiology, monitoring and implications of CSA-AKI, including potential preventive interventions. The review will provide the reader with an in-depth understanding of how to identify, support and provide a more personalized and tailored perioperative management to avoid development of CSA-AKI.

Postoperative acute kidney injury after thoracic endovascular aortic repair for acute type B aortic dissection

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) has evolved as the standard for treating complicated acute type B aortic dissection (ATBAD). Acute kidney injury (AKI) is a common complication in critically ill patients and is commonly observed in patients with ATBAD. The purpose of the study was to characterize AKI after TEVAR.

METHODS

All patients who underwent TEVAR for ATBAD from 2011 through 2021 were identified using the International Registry of Acute Aortic Dissection. The primary end point was AKI. A generalized linear model analysis was performed to identify a factor associated with postoperative AKI.

RESULTS

A total of 630 patients presented with ATBAD and underwent TEVAR. The indication for TEVAR was complicated ATBAD in 64.3%, high-risk uncomplicated ATBAD in 27.6%, and uncomplicated ATBAD in 8.1%. Of 630 patients, 102 (16.2%) developed postoperative AKI (AKI group) and 528 patients (83.8%) did not (non-AKI group). The most common indication for TEVAR was malperfusion (37.5%). In-hospital mortality was significantly higher in the AKI group (18.6% vs 4%; P < .001). Postoperatively, cerebrovascular accident, spinal cord ischemia, limb ischemia, and prolonged ventilation were more commonly observed in the AKI group. The expected mortality was similar at 2 years between the two groups (P = .51). Overall, the preoperative AKI was observed in 95 (15.7%) in the entire cohort consisting of 60 (64.5%) in the AKI group and 35 (6.8%) in the non-AKI group. A history of CKD (odds ratio, 4.6; 95% confidence interval, 1.5-14.1; P = .01) and preoperative AKI (odds ratio, 24.1; 95% confidence interval, 10.6-55.0; P < .001) were independently associated with postoperative AKI.

CONCLUSIONS

The incidence of postoperative AKI was 16.2% in patients undergoing TEVAR for ATBAD. Patients with postoperative AKI had a higher rate of in-hospital morbidities and mortality than those without. A history of CKD and preoperative AKI were independently associated with postoperative AKI.

Association of intraoperative cerebral and somatic tissue oxygen saturation with postoperative acute kidney injury in adult patients undergoing multiple valve surgery

BACKGROUND

The association between tissue oxygenation with postoperative acute kidney injury (AKI) in adult patients undergoing multiple valve surgery has not been specifically studied.

METHODS

In this prospective exploratory cohort study, 99 patients were enrolled. The left forehead, the left forearm, the left upper thigh, and the left renal region tissue oxygen saturation using near-infrared spectroscopy were monitored. The association between each threshold and AKI was assessed. The relative and absolute thresholds were < 70%, < 75%, < 80%, < 85%, < 90%, < 95%, and < 100% baseline, and baseline-standard deviation (SD), -1.5 SD, -2 SD, -2.5 SD, and -3 SD. Multivariate logistic regression analysis was adopted to explore the association.

RESULTS

AKI occurred in 53 (54%) patients. The absolute value-based SrrO2 thresholds associated with AKI were baseline-3 SD (odds ratio [OR], 4.629; 95% confidence interval [CI], 1.238-17.314; P = 0.023) and baseline-2.5 SD (OR, 2.842; 95% CI, 1.025-7.881; P = 0.045) after adjusting for the potential confounders, those are renal region tissue oxygen saturation of 55% and 60%, but not statistically significant after correcting for multiple testing (corrected P = 0.114 and 0.179, respectively).

CONCLUSION

The SrrO2 desaturation, defined as < baseline - 2.5 SD or < baseline - 3 SD, may be associated with AKI. The thresholds need to be verified in future large-scale studies.

TRIAL REGISTRATIONS

The study was registered at ClinicalTrials.gov, first trial registration: 26/10/2017, identifier: NCT03323203.

Kidney Injury after Cardiac Surgery: Prevention-Associated Cost Reduction

INTRODUCTION

Cardiac surgery may induce acute kidney injury and the need for renal replacement therapy. It is also associated with higher hospital costs, morbidity and mortality. The aims of this study were to investigate predictors of cardiac surgery associated acute kidney injury in our population and to determine the burden of acute kidney injury in elective cardiac surgery, evaluating the potential cost effectiveness of preventing it through the application of the Kidney Disease: Improving Global Outcomes bundle of care to high-risk patient groups identified by the [TIMP-2]x[IGFBP7] used as a screening test.

MATERIAL AND METHODS

In a University Hospital single-center retrospective cohort study we analyzed a consecutive sample of adults who underwent elective cardiac surgery between January and March 2015. A total of 276 patients were admitted during the study period. Data from all patients was analyzed until hospital discharge or the patient's death. The economic analysis was performed from the hospital costs' perspective.

RESULTS

Cardiac surgery associated acute kidney injury occurred in 86 patients (31%). After adjustment, higher preoperative serum creatinine (mg/L, ORadj = 1.09; 95% CI: 1.01 - 1.17), lower preoperative hemoglobin (g/dL, ORadj = 0.79; 95% CI: 0.67 - 0.94), chronic systemic hypertension (ORadj = 5.00; 95% CI: 1.67 - 15.02), an increase in cardiopulmonary bypass time (min, ORadj = 1.01; 95% CI: 1.00 - 1.01) and perioperative use of sodium nitroprusside (ORadj = 6.33; 95% CI: 1.80 - 22.28) remained significantly associated with cardiac surgery related acute kidney injury. The expected cumulative surplus cost for the hospital linked with cardiac surgery associated acute kidney injury (86 patients) was €120 695.84. Based on a median absolute risk reduction of 16.6%, by dosing kidney damage biomarkers in every patient and using preventive measures in high-risk patients, we would expect a break-even point upon screening 78 patients, which would translate, in our patient cohort, into an overall cost benefit of €7145.

CONCLUSION

Preoperative hemoglobin, serum creatinine, systemic hypertension, cardiopulmonary bypass time and perioperative use of sodium nitroprusside were independent predictors of cardiac surgery associated acute kidney injury. Our cost-effectiveness modelling suggests that the use of kidney structural damage biomarkers combined with an early prevention strategy could be associated with potential cost savings.

Serum Insulin-Like Growth Factor-Binding Protein 7 Deriving from Spleen and Lung Could Be Used for Early Recognition of Cardiac Surgery-Associated Acute Kidney Injury

INTRODUCTION

The utility of arithmetic product of urinary tissue metalloproteinase inhibitor 2 (TIMP2) and insulin-like growth factor-binding protein 7 (IGFBP7) concentrations has been widely accepted on early diagnosis of acute kidney injury (AKI). However, which organ is the main source of those two factors and how the concentration of IGFBP7 and TIMP2 changed in serum during AKI still remain to be defined.

METHODS

In mice, gene transcription and protein levels of IGFBP7/TIMP2 in the heart, liver, spleen, lung, and kidney were measured in both ischemia-reperfusion injury (IRI)- and cisplatin-induced AKI models. Serum IGFBP7 and TIMP2 levels were measured and compared in patients before cardiac surgery and at inclusion (0 h), 2 h, 6 h, and 12 h after intensive care unit (ICU) admission, and compared with serum creatinine (SCr), blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), and serum uric acid (UA).

RESULTS

In mouse IRI-AKI model, compared with the sham group, the expression levels of IGFBP7 and TIMP2 did not change in the kidney, but significantly upregulated in the spleen and lung. Compared with patients who did not develop AKI, the concentration of serum IGFBP7 at as early as 2 h after ICU admission (sIGFBP7-2 h) was significantly higher in patients who developed AKI. The relationships between sIGFBP7-2 h in AKI patients and log2 (SCr), log2 (BUN), log2 (eGFR), and log2 (UA) were statistically significant. The diagnostic performance of sIGFBP7-2 h measured by the macro-averaged area under the receiver operating characteristic curve was 0.948 (95% CI, 0.853-1.000; p < 0.001).

CONCLUSION

The spleen and lung might be the main source of serum IGFBP7 and TIMP2 during AKI. The serum IGFBP7 value demonstrated good predictive accuracy for AKI following cardiac surgery within 2 h after ICU admission.

DNA binding protein YB-1 is a part of the neutrophil extracellular trap mediation of kidney damage and cross-organ effects

Open-heart surgery is associated with high morbidity, with acute kidney injury (AKI) being one of the most commonly observed postoperative complications. Following open-heart surgery, in an observational study we found significantly higher numbers of blood neutrophils in a group of 13 patients with AKI compared to 25 patients without AKI (AKI: 12.9±5.4 ×109 cells/L; non-AKI: 10.1±2. 9 ×109 cells/L). Elevated serum levels of neutrophil extracellular trap (NETs) components, such as dsDNA, histone 3, and DNA binding protein Y-box protein (YB)-1, were found within the first 24 hours in patients who later developed AKI. We could demonstrate that NET formation and hypoxia triggered the release of YB-1, which was subsequently shown to act as a mediator of kidney tubular damage. Experimentally, in two models of AKI mimicking kidney hypoperfusion during cardiac surgery (bilateral ischemia/reperfusion (I/R) and systemic lipopolysaccharide (LPS) administration), a neutralizing YB-1 antibody was administered to mice. In both models, prophylactic YB-1 antibody administration significantly reduced the tubular damage (damage score range 1-4, the LPS model: non-specific IgG control, 0.92±0.23; anti-YB-1 0.65±0.18; and in the I/R model: non-specific IgG control 2.42±0.23; anti-YB-1 1.86±0.44). Even in a therapeutic, delayed treatment model, antagonism of YB-1 ameliorated AKI (damage score, non-specific IgG control 3.03±0.31; anti-YB-1 2.58±0.18). Thus, blocking extracellular YB-1 reduced the effects induced by hypoxia and NET formation in the kidney and significantly limited AKI, suggesting that YB-1 is part of the NET formation process and an integral mediator of cross-organ effects.

Impact of ketamine versus propofol for anesthetic induction on cognitive dysfunction, delirium, and acute kidney injury following cardiac surgery in elderly, high-risk patients

Objective

Evaluate the effects of ketamine versus propofol when used for induction of anesthesia in elderly, high-risk cardiac surgical patients on postoperative complications including cognitive dysfunction, delirium, and acute kidney injury.

Methods

Prospective, randomized study performed at a tertiary medical center. A total of 52 patients aged ≥70 and older presenting for complex cardiac surgery were randomized to receive either ketamine or propofol for induction of anesthesia. Patients underwent a battery of cognitive testing preoperatively and postoperatively and the incidence of delirium and acute kidney injury were measured. Norepinephrine (NEE) equivalents following induction were assessed for each group.

Results

A total of 49 patients were included, 25 in the ketamine group and 24 in the propofol group with 3 patients excluded from the analysis. No difference was found between groups in either postoperative cognitive dysfunction or delirium incidence. Acute kidney injury occurred in 6 (24%) patients in the ketamine group in 12 (50%) patients in the propofol group, but the difference did not meet statistical significance (P = 0.08; Relative Risk = 2.1, 95% CI 0.9-4.7). NEE equivalents were lower in the ketamine group, 9.6 ± 22.2 versus 32.7 ± 46.0, P < 0.03.

Conclusions

The use of ketamine versus propofol for induction of anesthesia did not impact the incidence of postoperative cognitive dysfunction or delirium. Twice as many patients in the propofol group developed acute kidney injury, although not reaching statistical significance and warranting further investigation. In elderly, high-risk patients, ketamine was associated with a significantly reduced need for vasopressor support following induction.

Implementation of the Kidney Disease Improving Global Outcomes guidelines for the prevention of acute kidney injury after cardiac surgery: An international cohort survey

BACKGROUND

Increasing evidence from randomised controlled trials supports the implementation of a six-measure care bundle proposed by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines in patients at high risk for acute kidney injury (AKI) to reduce its incidence after cardiac surgery.

OBJECTIVE

To assess compliance with the KDIGO bundle in clinical practice.

DESIGN

Prospective observational multinational study.

SETTING

Six international tertiary care centres, from February 2021 to November 2021.

PATIENTS

Five hundred and thirty-seven consecutive patients undergoing cardiac surgery during a 1-month observational period.

INTERVENTIONS

All patients were assessed for the postoperative implementation of the following measures: avoidance of nephrotoxic medication and radiocontrast agents whenever possible, strict glycaemic control, close monitoring of renal function, optimisation of haemodynamic and volume status and functional monitoring of haemodynamic status.

MAIN OUTCOME MEASURES

The primary endpoint was the proportion of patients receiving fully compliant care. Secondary outcomes were occurrence of AKI and major adverse kidney event rate at day 30.

RESULTS

The full care bundle was applied to 0.4% of patients. There was avoidance of nephrotoxic drugs in 15.6%, radiocontrast agents in 95.3% and hyperglycaemia in 39.6%. Close monitoring of urine output and serum creatinine was achieved in 6.3%, 57.4% underwent optimisation of volume and haemodynamic status, and 43.9% received functional haemodynamic monitoring. 27.2% developed AKI within 72 h after surgery. The average number of implemented measures was 2.6 ± 1.0 and did not differ between AKI or non-AKI patients ( P  = 0.854).

CONCLUSION

Adherence with the KDIGO bundle was very low in cardiac surgery patients. Initiatives to improve guideline compliance might provide a strategy to mitigate the burden of AKI.

TRIAL REGISTRATION

www.drks.de DRKS00024204.

Adult Cardiac Surgery-Associated Acute Kidney Injury: Joint Consensus Report

OBJECTIVES

Acute kidney injury (AKI) is increasingly recognized as a source of poor patient outcomes after cardiac surgery. The purpose of the present report is to provide perioperative teams with expert recommendations specific to cardiac surgery-associated AKI (CSA-AKI).

METHODS

This report and consensus recommendations were developed during a joint, in-person, multidisciplinary conference with the Perioperative Quality Initiative and the Enhanced Recovery After Surgery Cardiac Society. Multinational practitioners with diverse expertise in all aspects of cardiac surgical perioperative care, including clinical backgrounds in anesthesiology, surgery and nursing, met from October 20 to 22, 2021, in Sacramento, California, and used a modified Delphi process and a comprehensive review of evidence to formulate recommendations. The quality of evidence and strength of each recommendation were established using the Grading of Recommendations Assessment, Development, and Evaluation methodology. A majority vote endorsed recommendations.

RESULTS

Based on available evidence and group consensus, a total of 13 recommendations were formulated (4 for the preoperative phase, 4 for the intraoperative phase, and 5 for the postoperative phase), and are reported here.

CONCLUSIONS

Because there are no reliable or effective treatment options for CSA-AKI, evidence-based practices that highlight prevention and early detection are paramount. Cardiac surgery-associated AKI incidence may be mitigated and postsurgical outcomes improved by focusing additional attention on presurgical kidney health status; implementing a specific cardiopulmonary bypass bundle; using strategies to maintain intravascular euvolemia; leveraging advanced tools such as the electronic medical record, point-of-care ultrasound, and biomarker testing; and using patient-specific, goal-directed therapy to prioritize oxygen delivery and end-organ perfusion over static physiologic metrics.

Risk factors for early death after surgery in patients with acute Stanford type A aortic dissection: A systematic review and meta-analysis

BACKGROUND

There are many risk factors related to early death after surgery among patients with acute Stanford type A aortic dissection (ATAAD) that have been analyzed in previous studies, but no evidence-based study has been conducted to confirm these risk factors.

AIMS

The aims of this study were to investigate risk factors for early death after surgery in patients with ATAAD via systematic review and meta-analysis and assess evidence-based strategies for preventing adverse events.

METHODS

The protocol for this study was prospectively registered with PROSPERO (CRD 42022332772). The authors systematically searched PubMed, Ovid, Scopus, Web of Science and Cochrane Library following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines from database construction to May 2021. Studies that met the selection criteria were determined by two independent researchers, and the odds ratios (ORs) and 95% confidence intervals (95% CIs) were reported for the risk factors and were pooled using Stata 15.0.

RESULTS

A total of 23 studies including 5510 patients met the inclusion criteria, and 10 risk factors were analyzed in this meta-analysis. The preoperative risk factors for early death after surgery in patients with ATAAD were age [(OR: 1.03, 95% CI (1.01, 1.06)], male sex [(OR: 1.43, 95% CI (1.06, 1.92)], shock [(OR: 1.91, 95% CI (1.06, 3.45)], malperfusion [(OR: 3.45, 95% CI (2.24, 5.31)] and cardiac tamponade [(OR: 3.89, 95% CI (1.17, 12.98)].

CONCLUSION

Patients with ATAAD who have an older age, male sex, shock, malperfusion and cardiac tamponade have a higher risk for early death after surgery. However, more highly homogenous studies are needed to demonstrate these results. Clinical staff should pay more attention to these factors and take individual actions to reduce mortality after surgery in patients with ATAAD.

Comparison between ketorolac- and fentanyl-based patient-controlled analgesia for acute kidney injury after robot-assisted radical prostatectomy: a retrospective propensity score-matched analysis

PURPOSE

It is unclear whether ketorolac-based patient-controlled analgesia (PCA) leads to acute kidney injury (AKI) after robot-assisted radical prostatectomy (RARP) in patients susceptible to AKI. We compared the postoperative AKI incidence with ketorolac- and fentanyl-based PCA after RARP.

METHODS

After medical record review, eligible patients were divided in ketorolac and fentanyl groups. We conducted propensity score matching of 3239 patients and assigned 641 matched patients to each group, and compared the AKI incidence. We investigated potential risk factors for postoperative AKI, defined according to the Kidney Disease Improving Global Outcomes criteria. We collected preoperative data (age, height, weight, body mass index, American Society of Anesthesiologists physical status, medical history, creatinine level, estimated glomerular filtration rate, and hemoglobin level) and intraoperative data (maintenance anesthetics, surgery duration, anesthesia duration, crystalloid amount, colloid use, total amount of fluid administered, estimated blood loss, norepinephrine use, phenylephrine use, and PCA type).

RESULTS

The postoperative AKI incidence was significantly higher in the ketorolac than in the fentanyl group, both before (31.1% vs. 20.4%; p < 0.001) and after (31.5% vs. 22.6%; p < 0.001) matching. In the univariate analysis, ketorolac was significantly associated with postoperative AKI, both before (odds ratio [OR], 1.762; 95% confidence interval [CI], 1.475-2.105; p < 0.001) and after (OR, 1.574; 95% CI, 1.227-2.019; p < 0.001) matching. In the multivariate analysis, ketorolac-based PCA was independently associated with development of postoperative AKI in the matched groups (OR, 1.659; 95% CI, 1.283-2.147; p < 0.001).

CONCLUSION

Ketorolac-based PCA may increase postoperative AKI incidence after RARP; thus, renal function should be monitored in these patients.

Correlation between perioperative dexmedetomidine administration and postoperative acute kidney injury in hypertensive patients undergoing non-cardiac surgery

Background: Previous studies have suggested that dexmedetomidine may have a protective effect on renal function. However, it is currently unclear whether perioperative dexmedetomidine administration is associated with postoperative acute kidney injury (AKI) incidence risk in hypertensive patients undergoing non-cardiac surgery.

Methods: This investigation was a retrospective cohort study. Hypertensive patients undergoing non-cardiac surgery in Third Xiangya Hospital of Central South University from June 2018 to December 2019 were included. The relevant data were extracted through electronic cases. The univariable analysis identified demographic, preoperative laboratory, and intraoperative factors associated with acute kidney injury. Multivariable stepwise logistic regression was used to assess the association between perioperative dexmedetomidine administration and postoperative acute kidney injury after adjusting for interference factors. In addition, we further performed sensitivity analyses in four subgroups to further validate the robustness of the results.

Results: A total of 5769 patients were included in this study, with a 7.66% incidence of postoperative acute kidney injury. The incidence of postoperative acute kidney injury was lower in the dexmedetomidine-administered group than in the control group (4.12% vs. 8.06%, p &lt; 0.001). In the multivariable stepwise logistic regression analysis, perioperative dexmedetomidine administration significantly reduced the risk of postoperative acute kidney injury after adjusting for interference factors [odds ratio (OR) = 0.56, 95% confidence interval (CI): 0.36–0.87, p = 0.010]. In addition, sensitivity analysis in four subgroups indicated parallel findings: i) eGRF &lt;90 mL/min·1.73/m2 subgroup (OR = 0.40, 95% CI: 0.19–0.84, p = 0.016), ii) intraoperative blood loss &lt;1000 mL subgroup (OR = 0.58, 95% CI: 0.36–0.94, p = 0.025), iii) non-diabetes subgroup (OR = 0.51, 95% CI: 0.29–0.89, p = 0.018), and iv) older subgroup (OR = 0.55, 95% CI: 0.32–0.93, p = 0.027).

Conclusion: In conclusion, our study suggests that perioperative dexmedetomidine administration is associated with lower risk and less severity of postoperative acute kidney injury in hypertensive individuals undergoing non-cardiac surgery. Therefore, future large-scale RCT studies are necessary to validate this benefit.

Predictive role of arterial lactate in acute kidney injury associated with off-pump coronary artery bypass grafting

Objectives

This observational study aims to explore the predictive role of postoperative arterial lactate in off-pump coronary artery bypass grafting (CABG)-associated acute kidney injury (AKI).

Materials and methods

A total of 500 consecutive patients who underwent off-pump CABG from August 2020 to August 2021 at the Department of Cardiovascular Surgery, Qilu Hospital of Shandong University, were included. Logistic regression analysis was used to confirm the independent risk factors of off-pump CABG-associated AKI. Receiver operating characteristic (ROC) curve was performed to evaluate the discrimination ability and Hosmer–Lemeshow goodness of fit test was performed to evaluate the calibration ability.

Results

The incidence of off-pump CABG-associated AKI was 20.6%. Female gender, preoperative albumin, baseline serum creatinine, 12 h postoperative arterial lactate and duration of mechanical ventilation were independent risk factors. The area under the ROC curve (AUC) of 12 h postoperative arterial lactate for predicting off-pump CABG-associated AKI was 0.756 and the cutoff value was 1.85. The prediction model that incorporated independent risk factors showed reliable predictive ability (AUC = 0.846). Total hospital stay, intensive care unit stay, occurrence of other postoperative complications, and 28-day mortality were all significantly higher in AKI group compared to non-AKI group.

Conclusion

12 h postoperative arterial lactate was a validated predictive biomarker for off-pump CABG-associated AKI. We constructed a predictive model that facilitates the early recognition and management of off-pump CABG-associated AKI.

Algorithm-based detection of acute kidney injury according to full KDIGO criteria including urine output following cardiac surgery: a descriptive analysis

BACKGROUND

Automated data analysis and processing has the potential to assist, improve and guide decision making in medical practice. However, by now it has not yet been fully integrated in a clinical setting. Herein we present the first results of applying algorithm-based detection to the diagnosis of postoperative acute kidney injury (AKI) comprising patient data from a cardiac surgical intensive care unit (ICU).

METHODS

First, we generated a well-defined study population of cardiac surgical ICU patients by implementing an application programming interface (API) to extract, clean and select relevant data from the archived digital patient management system. Health records of N = 21,045 adult patients admitted to the ICU following cardiac surgery between 2012 and 2022 were analyzed. Secondly, we developed a software functionality to detect the incidence of AKI according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria, including urine output. Incidence, severity, and temporal evolution of AKI were assessed.

RESULTS

With the use of our automated data analyzing model the overall incidence of postoperative AKI was 65.4% (N = 13,755). Divided by stages, AKI 2 was the most frequent maximum disease stage with 30.5% of patients (stage 1 in 17.6%, stage 3 in 17.2%). We observed considerable temporal divergence between first detections and maximum AKI stages: 51% of patients developed AKI stage 2 or 3 after a previously identified lower stage. Length of ICU stay was significantly prolonged in AKI patients (8.8 vs. 6.6 days, p <  0.001) and increased for higher AKI stages up to 10.1 days on average. In terms of AKI criteria, urine output proved to be most relevant, contributing to detection in 87.3% (N = 12,004) of cases.

CONCLUSION

The incidence of postoperative AKI following cardiac surgery is strikingly high with 65.4% when using full KDIGO-criteria including urine output. Automated data analysis demonstrated reliable early detection of AKI with progressive deterioration of renal function in the majority of patients, therefore allowing for potential earlier therapeutic intervention for preventing or lessening disease progression, reducing the length of ICU stay, and ultimately improving overall patient outcomes.

Acute kidney injury after major non-cardiac surgery: Incidence and risk factors

BACKGROUND

Acute kidney injury (AKI) is a major post-surgical complication that contributes to morbidity and mortality. AKI is welldocumented after cardiac surgery. However, less is known regarding the incidence and risk factors following major non-cardiac surgery.Globally the incidence of AKI post major surgery has been evaluated; however, there are no data available for South Africa (SA).

OBJECTIVES

To ascertain the incidence of AKI after major non-cardiac surgery at a tertiary academic SA hospital. Secondary outcomes wereto identify perioperative risk factors that are associated with an elevated risk to develop AKI in the postoperative period.

METHODS

The study was conducted at Tygerberg Hospital, a single tertiary centre in Cape Town, SA. Perioperative records of adults whounderwent major non-cardiac surgery were retrospectively collected. Variables pertaining to potential risk factors for AKI were captured,and serum creatinine levels were recorded up to 7 days postoperatively and compared with baseline measurements to determine whetherAKI had developed. Descriptive statistics along with logistic regression analysis were used to interpret results.

RESULTS

The overall incidence of AKI was 11.2% (95% confidence interval (CI) 9.8 - 12.6). Based on surgical discipline, trauma surgery(19%), followed by abdominal (18.5%) and vascular surgery (17%) had the highest incidence. Independent AKI risk factors wereidentified after multivariate analysis. These were: chronic obstructive pulmonary disease (odds ratio (OR) 2.19; 95% CI 1.09 - 4.37;p=0.005), trauma surgery (OR 3.00; 95% CI 1.59 - 5.64; p=0.001), abdominal surgery (OR 2.14; 95% CI 1.33 - 3.45; p=0.002), vascularsurgery (OR 2.42; 95% CI 1.31 - 4.45; p=0.004), urology procedures (OR 2.45; 95% CI 1.31 - 4.45; p=0.005), red blood cell transfusion(OR 1.81; 95% CI 1.21 - 2.70; p=0.004), emergency surgery (OR 1.74; 95% CI 1.15 - 2.65; p=0.009) and inotrope use (OR 2.77; 95% CI1.80 - 4.26; p<0.001).

CONCLUSION

The results of our study are in keeping with international literature regarding the incidence of AKI after major non-cardiacsurgery. The risk factor profile, however, is in several regards different from what has been found elsewhere.

A novel predictive model for poor in-hospital outcomes in patients with acute kidney injury after cardiac surgery

OBJECTIVE

Patients with cardiac surgery-associated acute kidney injury are at risk of renal replacement therapy and in-hospital death. We aimed to develop and validate a novel predictive model for poor in-hospital outcomes among patients with cardiac surgery-associated acute kidney injury.

METHODS

A total of 196 patients diagnosed with cardiac surgery-associated acute kidney injury were enrolled in this study as the training cohort, and 32 blood cytokines were measured. Least absolute shrinkage and selection operator regression and random forest quantile-classifier were performed to identify the key blood predictors for in-hospital composite outcomes (requiring renal replacement therapy or in-hospital death). The logistic regression model incorporating the selected predictors was validated internally using bootstrapping and externally in an independent cohort (n = 52).

RESULTS

A change in serum creatinine (delta serum creatinine) and interleukin 16 and interleukin 8 were selected as key predictors for composite outcomes. The logistic regression model incorporating interleukin 16, interleukin 8, and delta serum creatinine yielded the optimal performance, with decent discrimination (area under the receiver operating characteristic curve: 0.947; area under the precision-recall curve: 0.809) and excellent calibration (Brier score: 0.056, Hosmer-Lemeshow test P = .651). Application of the model in the validation cohort yielded good discrimination. A nomogram was generated for clinical use, and decision curve analysis demonstrated that the new model adds more net benefit than delta serum creatinine.

CONCLUSIONS

We developed and validated a promising predictive model for in-hospital composite outcomes among patients with cardiac surgery-associated acute kidney injury and demonstrated interleukin-16 and interleukin-8 as useful predictors to improve risk stratification for poor in-hospital outcomes among those with cardiac surgery-associated acute kidney injury.

Defining a postoperative mean arterial pressure threshold in association with acute kidney injury after cardiac surgery: a prospective observational study

Acute kidney injury (AKI) is a common but fatal complication after cardiac surgery. In the absence of effective treatments, the identification and modification of risk factors has been a major component of disease management. However, the optimal blood pressure target for preventing cardiac surgery-associated acute kidney injury (CSA-AKI) remains unclear. We sought to determine the effect of postoperative mean arterial pressure (MAP) in CSA-AKI. It is hypothesized that longer periods of hypotension after cardiac surgery are associated with an increased risk of AKI. This prospective cohort study was conducted on adult patients who underwent cardiac surgery requiring cardiopulmonary bypass at a tertiary center between October 2018 and May 2020. The primary outcome is the occurrence of CSA-AKI. MAP and its duration in the ranges of less than 65, 65 to 74, and 75 to 84 mmHg within 24 h after surgery were recorded. The association between postoperative MAP and CSA-AKI was examined by using logistic regression. Among the 353 patients enrolled, 217 (61.5%) had a confirmed diagnosis of CSA-AKI. Each 1 h epoch of postoperative MAP less than 65 mmHg was associated with an adjusted odds ratio of 1.208 (95% CI, 1.007 to 1.449; P = 0.042), and each 1 h epoch of postoperative MAP between 65 and 74 mmHg was associated with an adjusted odds ratio of 1.144 (95% CI, 1.026 to 1.275; P = 0.016) for CSA-AKI. A potentially modifiable risk factor, postoperative MAP less than 75 mmHg for 1 h or more is associated with an increased risk of CSA-AKI.

The association of coagulation indicators with in-hospital acute kidney injury and malignant events of patients with acute aortic dissection: a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) is a prevalent complication of acute aortic dissection (AAD) and is associated with poor outcomes. The onset of AAD may result in endothelial injury due to the formation of the false lumen, which can activate the coagulation pathway and lead to coagulation dysfunction. It serves as a valuable diagnostic and prognostic marker for AAD, but also plays a role in the pathological mechanisms underlying AKI. We aimed to investigate the potential value of coagulation indicators at admission for assessing in-hospital AKI and malignant events after AAD.

METHODS

We identified patients with AAD admitted to the First Affiliated Hospital of Shantou University Medical College from January 2015 to October 2020 and divided them into two groups according to coagulation function. Univariable and multivariable analyses were used to analyze the association between coagulation indicators and AKI and malignant events in patients with AAD. Chi-squared or Fisher exact test and receiver operating characteristic (ROC) curve analysis was conducted to assess the value of coagulation indicators in predicting in-hospital AKI and malignant events.

RESULTS

A total of 487 patients were enrolled in this study, including 309 cases with normal coagulation. After the multivariable adjustment, the incidence of in-hospital AKI in the abnormal coagulation group was significantly higher [model 1: 2.061 (1.214-3.501), P=0.007; model 2: 1.833 (1.058-3.177), P=0.031; model 3: 1.836 (1.048-3.216), P=0.034]. The incidence of malignant events was higher in the abnormal prothrombin time (PT) group [model 1: 4.283 (0.983-18.665), P=0.053; model 2: 7.342 (1.467-36.749), P=0.015; model 3: 6.996 (1.377-35.537), P=0.019]. Chi-squared and Fisher exact test showed that PT and abnormal coagulation score (ACS) were statistically different among the AKI groups and malignant event groups. Under ROC analysis, coagulation indicators were helpful to predict AKI (AUC =0.668; P<0.001).

CONCLUSIONS

Our study confirmed the presence of coagulation dysfunction is associated with an increased risk of AKI and malignant events. It suggested the severity of coagulation dysfunction is positively correlated with the incidence of in-hospital AKI in AAD patients. These results highlight the importance of considering coagulation dysfunction as a potential mechanism underlying AKI and malignant events after AAD.

Sepsis-associated acute kidney injury: consensus report of the 28th Acute Disease Quality Initiative workgroup

Sepsis-associated acute kidney injury (SA-AKI) is common in critically ill patients and is strongly associated with adverse outcomes, including an increased risk of chronic kidney disease, cardiovascular events and death. The pathophysiology of SA-AKI remains elusive, although microcirculatory dysfunction, cellular metabolic reprogramming and dysregulated inflammatory responses have been implicated in preclinical studies. SA-AKI is best defined as the occurrence of AKI within 7 days of sepsis onset (diagnosed according to Kidney Disease Improving Global Outcome criteria and Sepsis 3 criteria, respectively). Improving outcomes in SA-AKI is challenging, as patients can present with either clinical or subclinical AKI. Early identification of patients at risk of AKI, or at risk of progressing to severe and/or persistent AKI, is crucial to the timely initiation of adequate supportive measures, including limiting further insults to the kidney. Accordingly, the discovery of biomarkers associated with AKI that can aid in early diagnosis is an area of intensive investigation. Additionally, high-quality evidence on best-practice care of patients with AKI, sepsis and SA-AKI has continued to accrue. Although specific therapeutic options are limited, several clinical trials have evaluated the use of care bundles and extracorporeal techniques as potential therapeutic approaches. Here we provide graded recommendations for managing SA-AKI and highlight priorities for future research.

AKI3-Risk Predictors and Scores in Radical Nephrectomy with High Thrombectomy under Extracorporeal Circulation for Renal Cell Carcinoma with Supradiaphragmatic Inferior Vena Cava/Right Atrial Thrombus: A Single-Centre Retrospective Study

Background and Objectives: The recommended therapeutic management in renal cell carcinoma (RCC) with supradiaphragmatic inferior vena cava/right atrial thrombus (IVC/RA) is surgery. Extracorporeal circulation is required. Acute kidney injury (AKI), a frequent complication after nephrectomy and cardiac surgery is associated with long-term kidney disease. This study aims to identify the risk factors involved in the occurrence of the severe postoperative AKI (AKI3) and to analyse various preoperative validated risk scores from cardiac and noncardiac surgery in predicting this endpoint. Materials and Methods: The medical data of all patients with RCC with supradiaphragmatic IVC/RA thrombus who underwent radical nephrectomy with high thrombectomy, using extracorporeal circulation, between 2004-2018 in the Prof. C. C. Iliescu Emergency Institute for Cardiovascular Diseases, Bucharest, were retrospectively analysed. The patients who died intraoperatively were excluded from the study. The predefined study endpoint was the postoperative AKI3. Preoperative, intraoperative and postoperative data were collected according to the stratification of study population in two subgroups: AKI3-present and AKI3- absent patients. EuroSCORE, EuroSCORE II, Logistic EuroSCORE, NSQIP any-complications and NSQIP serious-complications were analysed. Results: We reviewed 30 patients who underwent this complex surgery between 2004-2018 in our institute. Two patients died intraoperatively. Nine patients (32.14%) presented postoperative AKI3. Age (OR 1.151, CI 95%: 1.009-1.312), preoperative creatinine clearance (OR 1.066, CI 95%: 1.010-1.123) and intraoperative arterial hypotension (OR 13.125, CI 95%: 1.924-89.515) were risk factors for AKI3 (univariable analysis). Intraoperative arterial hypotension emerged as the only independent risk factor in multivariable analysis (OR 11.66, CI 95%: 1.400-97.190). Logistic EuroSCORE (ROC analysis: AUC = 0.813, p = 0.008, CI 95%: 0.633-0.993) best predicted the endpoint. Conclusions: An integrated team effort is essential to avoid intraoperative arterial hypotension, the only independent risk factor of AKI3 in this highly complex surgery. Some risk scores can predict this complication. Further studies are needed.

The effect of preoperative statins on postoperative mortality, renal, and neurological complications in patients undergoing cardiac surgeries: a retrospective cohort study

BACKGROUND

Cardiac surgery is performed worldwide to treat severe cases of cardiovascular diseases. Statins have shown controversial effects on complications after cardiac surgeries. We aimed to investigate the effect of preoperative statin therapy on the frequency of postoperative mortality, renal, and neurological complications.

METHODS

In a retrospective cohort study, the database of patients operated on in two hospitals in southern Iran during 2008-2019 was used to compare preoperative statin use with no use on the composite outcome of mortality, renal, and neurological complications as well as on each component of the composite, separately. Effects of low dose (<40 mg simvastatin equivalence) vs. high dose (≥40 mg) statins were also evaluated. Confounders that could affect the outcomes were considered in the logistic regression model, and multiple imputation techniques were used to categorize patients with unknown statin dose use as either high or low-dose users.

RESULTS

Of total 7329 patients, 17.6% of statin users and 17% of non-statin users developed the composite outcome (P=0.51). Statin use had no statistically significant association with the composite outcome (aRR 1.01 [95% CI: 0.88-1.16]). There was no significant association with mortality [aRR: 0.75 (95% CI: 0.34-1.69)], neurological [aRR: 1.25 (95% CI: 0.77-2.12)], or renal complications [aRR: 1.03 (95% CI 0.90-1.19)] after surgery. Neither low nor high doses had any statistically significant effect on the composite or any of its components.

CONCLUSIONS

In this large study, preoperative statin use, either high dose or low dose, did not affect short-term postoperative mortality, neurological, or renal complications.

The prognostic value of elevated neutrophil-lymphocyte ratio for cardiac surgery-associated acute kidney injury: A systematic review and meta-analysis

BACKGROUND

Patients undergoing cardiac surgery are at significant risk of developing postoperative acute kidney injury (AKI). Neutrophil-lymphocyte ratio (NLR) is a widely available inflammatory biomarker which may be of prognostic value in this setting.

METHODS

We conducted a systematic review and meta-analysis of studies reporting associations between perioperative NLR with postoperative AKI. We searched Medline, Embase and the Cochrane Library, without language restriction, from inception to May 2022 for relevant studies. We meta-analysed the reported odds ratios (ORs) with 95% confidence intervals (CIs) for both elevated preoperative and postoperative NLR with risk of postoperative AKI and need for renal replacement therapy (RRT). We conducted a meta-regression to explore inter-study statistical heterogeneity.

RESULTS

Twelve studies involving 10,724 participants undergoing cardiac surgery were included, with eight studies being deemed at high risk of bias using PROBAST modelling. We found statistically significant associations between elevated preoperative NLR and postoperative AKI (OR 1.45, 95% CI 1.18-1.77), as well as postoperative need for RRT (OR 2.37, 95% CI 1.50-3.72). Postoperative NLR measurements were not of prognostic significance.

CONCLUSIONS

Elevated preoperative NLR is a reliable inflammatory biomarker for predicting AKI following cardiac surgery.

Risk of graft loss in kidney transplant recipients after aortic valve replacement

Surgical aortic valve replacement (SAVR) in kidney transplant recipients (KTR) is associated with high morbidity and mortality, and an increased risk of postoperative graft failure potentially leading to graft loss. Transcatheter aortic valve implantation (TAVI) emerged as an alternative in high-risk patients. However, data on TAVI in kidney transplant recipients are limited. We performed a retrospective analysis of 40 KTR in which aortic valve replacement was performed at our center between 2005 and 2015. The outcomes and follow-up of TAVI (n=20; 2010-2015) and SAVR (n=20; 2005-2015) were analyzed with respect to patient and graft survival. Baseline characteristics in both groups were comparable. Hospital stay after TAVI was significantly shorter compared to SAVR (19 [11.5-21.75] days vs. 33 [21-62] days, p=0.001). Acute graft failure occurred more frequently after SAVR (45% vs. 89.5%; p=0.006). Thirty-day mortality was 10% in both groups. However, in-hospital mortality reached 25% in the SAVR group (TAVI 10%), indicating a more complicated course after surgery. Moreover, during a median follow-up time of 1928 days in TAVI patients and 2717 days in patients after SAVR, graft loss occurred only in the surgically treated group (n=7). While one-year survival after TAVR was 90% compared to 69% after SAVR, long-term follow-up showed comparable results (at 5 years: TAVI 58% vs. 52% SAVR; log-rank-test: p=0.86). In KTR, TAVI can be performed with good mid- to long-term results. Compared to SAVR, renal outcomes seem to be improved after TAVI, suggesting better graft survival.

Diagnosis, pathophysiology and preventive strategies for cardiac surgery-associated acute kidney injury: a narrative review

Acute kidney injury (AKI) is a common and serious complication of cardiac surgery and is associated with increased mortality and morbidity, accompanied by a substantial economic burden. The pathogenesis of cardiac surgery-associated acute kidney injury (CSA-AKI) is multifactorial and complex, with a variety of pathophysiological theories. In addition to the existing diagnostic criteria, the exploration and validation of biomarkers is the focus of research in the field of CSA-AKI diagnosis. Prevention remains the key to the management of CSA-AKI, and common strategies include maintenance of renal perfusion, individualized blood pressure targets, balanced fluid management, goal-directed oxygen delivery, and avoidance of nephrotoxins. This article reviews the pathogenesis, definition and diagnosis, and pharmacological and nonpharmacological prevention strategies of AKI in cardiac surgical patients.

Low preoperative serum fibrinogen level is associated with postoperative acute kidney injury in patients with in acute aortic dissection

OBJECTIVE

Acute kidney injury (AKI) after cardiac surgery is associated with serious complication and high risk of mortality. The relationship between hemostatic system and the prognosis of patients with acute type A aortic dissection (ATAAD) has not been evaluated. The purpose of this study was to investigate the association between preoperative serum fibrinogen level and risk of postoperative AKI in patients with ATAAD.

METHODS

A total of 172 consecutive patients undergoing urgent aortic arch surgery for ATAAD between April 2020 and December 2021 were identified from Beijing Anzhen Hospital aortic surgery database. The primary outcome was postoperative AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria. The univariate and multivariate logistic regression analysis were done to assess the independent predictors of risk for postoperative AKI. Receiver operating characteristic (ROC) curve was generated to evaluate the predictive probabilities of risk factors for AKI.

RESULTS

In our study, 51.2% (88/172) patients developed postoperative AKI. Multivariate logistic regression analysis identified low preoperative serum fibrinogen level (OR, 1.492; 95% CI, 1.023 to 2.476; p = 0.021) and increased body mass index (BMI) (OR, 1.153; 95% CI, 1.003 to 1.327; p = 0.046) as independent predictors of postoperative AKI in patients with ATAAD. A mixed effect analysis of variance modeling revealed that obese patients with low preoperative serum fibrinogen level had higher incidence of postoperative AKI (p = 0.04). The ROC curve indicated that low preoperative serum fibrinogen level was a significant predictor of AKI [area under the curve (AUC), 0.771; p < 0.001].

CONCLUSIONS

Low preoperative serum fibrinogen level and obesity were associated with the risk of postoperative AKI in patients with ATAAD. These data suggested that low preoperative serum fibrinogen level was preferred marker for predicting the postoperative AKI, especially in obese patients with ATAAD.

The preoperative plasma histamine level as a possible protective biomarker for postoperative acute kidney injury

Acute kidney injury (AKI) is a life-threatening complication of acute type A aortic dissection (ATAAD) patients. Increasing evidence suggests that histamine ameliorates the pathology of renal injury. However, data on the association between histamine levels and postoperative AKI in ATAAD patients are limited. The purpose of our study was to explore the incidence and independent risk factors of postoperative AKI, with special emphasis on the relationship between preoperative plasma histamine levels and the severity of postoperative ATAAD-AKI. This retrospective single-center study evaluated 160 patients with ATAAD admitted to the Beijing Anzhen Hospital aortic surgery database between April 2020 and December 2021. Univariate and multivariate logistic regression analyses were performed to determine the potential risk factors for postoperative ATAAD-AKI. A subgroup analysis was performed to investigate the association between preoperative plasma histamine levels and the severity of postoperative ATAAD-AKI or continuous renal replacement therapy (CRRT). ATAAD-AKI occurred in 84 of 160 patients (52.5%), including 32 with stage 1 (38.1%), 14 with stage 2 (16.7%), 38 with stage 3 (45.2%), and 34 (21.3%) received postoperative CRRT. The in-hospital mortality rate was 19.0% (16/84) in the AKI group and 2.6% (2/76) in the non-AKI group (P = .02). Preoperative lower plasma histamine levels (odds ratio [OR], 1.31; 95% confidence interval [CI], 1.10-1.52; P = .004) were an important factor related to postoperative ATAAD-AKI in multivariate logistic regression analysis. Subgroup analysis revealed that low preoperative plasma histamine level was independently associated with postoperative ATAAD-AKI (stage 3) (OR, 1.38; 95% CI, 1.10-1.73; P = .005) and CRRT (OR, 1.44; 95% CI, 1.13-1.79; P = .008). Low preoperative plasma histamine level was an independent prognostic indicator of postoperative AKI in patients with ATAAD, especially for postoperative AKI (stage 3) and CRRT. Preoperative plasma histamine levels may serve as potential protective biomarkers of postoperative ATAAD-AKI.

Machine Learning-Based Prediction of Acute Kidney Injury Following Pediatric Cardiac Surgery: Model Development and Validation Study

BACKGROUND

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a major complication following pediatric cardiac surgery, which is associated with increased morbidity and mortality. The early prediction of CSA-AKI before and immediately after surgery could significantly improve the implementation of preventive and therapeutic strategies during the perioperative periods. However, there is limited clinical information on how to identify pediatric patients at high risk of CSA-AKI.

OBJECTIVE

The study aims to develop and validate machine learning models to predict the development of CSA-AKI in the pediatric population.

METHODS

This retrospective cohort study enrolled patients aged 1 month to 18 years who underwent cardiac surgery with cardiopulmonary bypass at 3 medical centers of Central South University in China. CSA-AKI was defined according to the 2012 Kidney Disease: Improving Global Outcomes criteria. Feature selection was applied separately to 2 data sets: the preoperative data set and the combined preoperative and intraoperative data set. Multiple machine learning algorithms were tested, including K-nearest neighbor, naive Bayes, support vector machines, random forest, extreme gradient boosting (XGBoost), and neural networks. The best performing model was identified in cross-validation by using the area under the receiver operating characteristic curve (AUROC). Model interpretations were generated using the Shapley additive explanations (SHAP) method.

RESULTS

A total of 3278 patients from one of the centers were used for model derivation, while 585 patients from another 2 centers served as the external validation cohort. CSA-AKI occurred in 564 (17.2%) patients in the derivation cohort and 51 (8.7%) patients in the external validation cohort. Among the considered machine learning models, the XGBoost models achieved the best predictive performance in cross-validation. The AUROC of the XGBoost model using only the preoperative variables was 0.890 (95% CI 0.876-0.906) in the derivation cohort and 0.857 (95% CI 0.800-0.903) in the external validation cohort. When the intraoperative variables were included, the AUROC increased to 0.912 (95% CI 0.899-0.924) and 0.889 (95% CI 0.844-0.920) in the 2 cohorts, respectively. The SHAP method revealed that baseline serum creatinine level, perfusion time, body length, operation time, and intraoperative blood loss were the top 5 predictors of CSA-AKI.

CONCLUSIONS

The interpretable XGBoost models provide practical tools for the early prediction of CSA-AKI, which are valuable for risk stratification and perioperative management of pediatric patients undergoing cardiac surgery.