Risk Factors for Acute Kidney Injury after Congenital Cardiac Surgery in Infants and Children: A Retrospective Observational Study

Incidence, Risk Factors and Outcomes of Acute Kidney Injury in Neonates Undergoing Open-heart Surgeries: Single Center Experience

Background

Incidence and outcomes of acute kidney injury (AKI) among neonates who underwent open-heart surgery are not well highlighted in the literature. We aim to assess the incidence, risk factors, and outcome of AKI among neonates undergoing open-heart surgery.

Methods

This is a retrospective cohort study between 2016 and 2021 for all neonates requiring open heart surgery. The cases were divided into 2 groups: the AKI (index) group and the non-AKI (control) group. The two groups were statistically compared for risk factors, needs for dialysis, and outcomes.

Results

100 patients fulfilled the inclusion criteria. Among them, 74 (74%) developed AKI, including 41 (55%), 15 (21%), and 18 (24%) patients in KDIGO stages 1, 2, and 3, respectively. Multivariate analysis comparing both groups demonstrated that low pre-operative creatinine (p = 0.01), prolonged bypass time (p = 0.0004) and high vasoactive inotropic score (VIS), (p = 0.0008) were risk factors for developing AKI post-operatively. Furthermore, in the AKI group, 17 (23%) neonates required renal replacement therapy in the form of peritoneal dialysis. The length of stay was higher in the AKI index group (p = 0.015). Patients who had AKI recovered their kidney function at discharge. There was no difference in mortality between both groups.

Conclusion

The AKI occurred in 74% of neonates undergoing open-heart surgery, with 23% of them needing peritoneal dialysis. Low pre-operative creatinine, high VIS score, and prolonged bypass time are potential risk factors for AKI development after neonatal open-heart surgery. AKI may lead to prolonged hospitalization, though most affected patients recovered their normal kidney function at discharge.

Predictors of augmented renal clearance based on iohexol plasma clearance in critically ill children

BACKGROUND

Augmented renal clearance (ARC) holds a risk of subtherapeutic drug concentrations. Knowledge of patient-, disease-, and therapy-related factors associated with ARC would allow predicting which patients would benefit from intensified dosing regimens. This study aimed to identify ARC predictors and to describe ARC time-course in critically ill children, using iohexol plasma clearance (CLiohexol) to measure glomerular filtration rate (GFR).

METHODS

This is a retrospective analysis of data from the "IOHEXOL" study which validated GFR estimating formulas (eGFR) against CLiohexol. Critically ill children with normal serum creatinine were included, and CLiohexol was performed as soon as possible after pediatric intensive care unit (PICU) admission (CLiohexol1) and repeated (CLiohexol2) after 48-72 h whenever possible. ARC was defined as CLiohexol exceeding normal GFR for age plus two standard deviations.

RESULTS

Eighty-five patients were included; 57% were postoperative patients. Median CLiohexol1 was 122 mL/min/1.73 m2 (IQR 75-152). Forty patients (47%) expressed ARC on CLiohexol1. Major surgery other than cardiac surgery and eGFR were found as independent predictors of ARC. An eGFR cut-off value of 99 mL/min/1.73 m2 and 140 mL/min/1.73 m2 was suggested to identify ARC in children under and above 2 years, respectively. ARC showed a tendency to persist on CLiohexol2.

CONCLUSIONS

Our findings raise PICU clinician awareness about increased risk for ARC after major surgery and in patients with eGFR above age-specific thresholds. This knowledge enables identification of patients with an ARC risk profile who would potentially benefit from a dose increase at initiation of treatment to avoid underexposure.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05179564, registered retrospectively on January 5, 2022.

Persistent acute kidney injury and fluid accumulation with outcomes after the Norwood procedure: report from NEPHRON

BACKGROUND

Cardiac surgery-associated acute kidney injury (CS-AKI) is common, but its impact on clinical outcomes is variable. Parsing AKI into sub-phenotype(s) and integrating pathologic positive cumulative fluid balance (CFB) may better inform prognosis. We sought to determine whether durational sub-phenotyping of CS-AKI with CFB strengthens association with outcomes among neonates undergoing the Norwood procedure.

METHODS

Multicenter, retrospective cohort study from the Neonatal and Pediatric Heart and Renal Outcomes Network. Transient CS-AKI: present only on post-operative day (POD) 1 and/or 2; persistent CS-AKI: continued after POD 2. CFB was evaluated per day and peak CFB during the first 7 postoperative days. Primary and secondary outcomes were mortality, respiratory support-free and hospital-free days (at 28, 60 days, respectively). The primary predictor was persistent CS-AKI, defined by modified neonatal Kidney Disease: Improving Global Outcomes criteria.

RESULTS

CS-AKI occurred in 59% (205/347) neonates: 36.6% (127/347) transient and 22.5% (78/347) persistent; CFB > 10% occurred in 18.7% (65/347). Patients with either persistent CS-AKI or peak CFB > 10% had higher mortality. Combined persistent CS-AKI with peak CFB > 10% (n = 21) associated with increased mortality (aOR: 7.8, 95% CI: 1.4, 45.5; p = 0.02), decreased respiratory support-free (predicted mean 12 vs. 19; p < 0.001) and hospital-free days (17 vs. 29; p = 0.048) compared to those with neither.

CONCLUSIONS

The combination of persistent CS-AKI and peak CFB > 10% after the Norwood procedure is associated with mortality and hospital resource utilization. Prospective studies targeting intra- and postoperative CS-AKI risk factors and reducing CFB have the potential to improve outcomes.

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.

Fluid assessment, fluid balance, and fluid overload in sick children: a report from the Pediatric Acute Disease Quality Initiative (ADQI) conference

BACKGROUND

The impact of disorders of fluid balance, including the pathologic state of fluid overload in sick children has become increasingly apparent. With this understanding, there has been a shift from application of absolute thresholds of fluid accumulation to an appreciation of the intricacies of fluid balance, including the impact of timing, trajectory, and disease pathophysiology.

METHODS

The 26th Acute Disease Quality Initiative was the first to be exclusively dedicated to pediatric and neonatal acute kidney injury (pADQI). As part of the consensus panel, a multidisciplinary working group dedicated to fluid balance, fluid accumulation, and fluid overload was created. Through a search, review, and appraisal of the literature, summative consensus statements, along with identification of knowledge gaps and recommendations for clinical practice and research were developed.

CONCLUSIONS

The 26th pADQI conference proposed harmonized terminology for fluid balance and for describing a pathologic state of fluid overload for clinical practice and research. Recommendations include that the terms daily fluid balance, cumulative fluid balance, and percent cumulative fluid balance be utilized to describe the fluid status of sick children. The term fluid overload is to be preserved for describing a pathologic state of positive fluid balance associated with adverse events. Several recommendations for research were proposed including focused validation of the definition of fluid balance, fluid overload, and proposed methodologic approaches and endpoints for clinical trials.

Development and Validation of a Nomogram for Predicting Acute Kidney Injury in Pediatric Patients Undergoing Cardiac Surgery

Acute kidney injury (AKI) is a common complication after cardiac surgery and associated with adverse outcomes. The purpose of this study is to construct a nomogram to predict the probability of postoperative AKI in pediatric patients undergoing cardiac surgery. We conducted a single-center retrospective cohort study of 1137 children having cardiac surgery under cardiopulmonary bypass. We randomly divided the included patients into development and validation cohorts at a ratio of 7:3. The least absolute shrinkage and selection operator regression model was used for feature selection. We constructed a multivariable logistic regression model to select predictors and develop a nomogram to predict AKI risk. Discrimination, calibration and clinical benefit of the final prediction model were evaluated in the development and validation cohorts. A simple nomogram was developed to predict risk of postoperative AKI using six predictors including age at operation, cyanosis, CPB duration longer than 120 min, cross-clamp time, baseline albumin and baseline creatinine levels. The area under the receiver operator characteristic curve of the nomogram was 0.739 (95% CI 0.693-0.786) and 0.755 (95% CI 0.694-0.816) for the development and validation cohort, respectively. The calibration curve showed a good correlation between predicted and observed risk of postoperative AKI. Decision curve analysis presented great clinical benefit of the nomogram. This novel nomogram for predicting AKI after pediatric cardiac surgery showed good discrimination, calibration and clinical practicability.

Acute kidney injury after arterial switch operation: incidence, risk factors, clinical impact - a retrospective single-center study

BACKGROUND

This retrospective study aimed to determine the incidence, risk factors, and outcomes of acute kidney injury (AKI) in neonates following the arterial switch operation (ASO) for transposition of great arteries (TGA).

METHODS

Retrospective review of medical data of children who underwent ASO in 2019-2020 in the Ukrainian Children's Cardiac Center.

RESULTS

76 consecutive neonatal patients were included, 48 developed AKI after ASO (51.7%), and 24 - had severe AKI (25.8%). Severe AKI development was associated with longer cross-clamp time: 82 (61-127) versus 73.5 (53-136) in the non-severe AKI group (p = 0.02). 76 min of cross-clamp time were defined as a threshold value for increased severe AKI risk, OR 4.4 (95% CI: 1.5 - 13, p = 0.01). Higher lactate levels during cardiopulmonary bypass (CPB) increased severe AKI development risk, OR 1.5 (95% CI: 1.0 - 2.0, p = 0.03). Children with severe AKI had prolonged mechanical ventilation, longer time to negative fluid balance, and higher postoperative day 3 (POD3) Inotropic Score (IS). Only one patient required peritoneal dialysis.

CONCLUSIONS

In our study, 51.7% of patients developed AKI after ASO, 25.8%-severe AKI. Prolonged cross-clamp time and higher lactate levels during cardiopulmonary bypass increased the risk for severe AKI development. The development of AKI was associated with prolonged mechanical ventilation, longer time to negative fluid balance, higher POD 3 Inotropic Score.

Intraoperative Transfusion of Autologous Blood Protects from Acute Kidney Injury after Pediatric Congenital Heart Surgery

Background

Acute kidney injury (AKI) is a common complication after pediatric cardiac surgery. And autologous blood transfusion (ABT) is an important predictor of postoperative AKI. Unlike previous studies, which mainly focused on the correlation between ABT and AKI, the current study focuses heavily on the causal relationship between them, thus providing guidance for the treatment of patients during hospitalization to reduce the occurrence of AKI.

Methods

A retrospective cohort of 3386 patients extracted from the Pediatric Intensive Care database was used for statistical analysis, multifactorial analysis, and causal inference. Characteristics that were correlated with ABT and AKI were categorized as confounders, instrumental variables, and effect modifiers, and were entered into the DoWhy causal inference model to determine causality. The calculated average treatment effect (ATE) was compared with the results of the multifactorial analysis.

Results

The adjusted odds ratio (OR) for ABT volume was obtained by multifactorial analysis as 0.964. The DoWhy model refute test was able to indicate a causal relationship between ABT and AKI. Any ABT reduces AKI about 15.3%-18.8% by different estimation methods. The ATE regarding the amount of ABT was -0.0088, suggesting that every 1 mL/kg of ABT reduced the risk of AKI by 0.88%.

Conclusions

Intraoperative transfusion of autologous blood can have a protective effect against postoperative AKI.

Cardiopulmonary bypass in neonates and infants: advantages of high flow high hematocrit bypass strategy-clinical practice review

Cardiopulmonary bypass is an integral and indispensable part of surgical repair of congenital heart defects. While the complications and morbidity secondary to the use of cardiopulmonary bypass has decreased considerably, there remains a significant incidence of clinically relevant renal and neurological injury. To provide more physiological delivery of oxygenated blood to the end-organs, our center has been successfully using a high-flow, high hematocrit cardiopulmonary bypass strategy since 2006. The essential components of this strategy include maintaining high flows (typically 200 mL/kg/min in neonates, 150-175 mL/kg/min in older infants weighing <10 kg, and 2.6 L/min/m2 in older children) throughout the duration of cardiopulmonary bypass irrespective of patient temperature, as well as maintaining a hematocrit of at least 32% on cardiopulmonary bypass. The incidence of post-operative acute kidney injury (around 3%) and clinical acute neurological events (<1%) with this strategy is considerably less when compared to other contemporary publications using the conventional cardiopulmonary bypass strategy. In this review, we discuss the rationale behind our approach and present evidence to support the high-flow, high-hematocrit strategy. We also discuss the practical aspects of our strategy and describe the adjuncts we use to derive additional benefits. These adjuncts include the use of a hybrid pH/alpha stat strategy during cooling/rewarming, aggressive use of conventional ultrafiltration during cardiopulmonary bypass, a terminal hematocrit of 40-45%, and avoidance of milrinone and albumin in the early peri-operative period. This results in a very low incidence of post-operative bleeding, facilitates chest closure in the operating room even in most neonates, helps in reducing the need for post-operative blood product transfusion and helps in achieving a favorable post-operative fluid balance early after surgery.

Contrast-Associated Acute Kidney Injury Requiring Continuous Renal Replacement Therapy in A Neonate with Aortic Stenosis-A Case Report

BACKGROUND

Acute kidney injury occurs commonly in the Neonatal Intensive Care Unit and is associated with increased mortality and morbidity. We report a case of a neonate with congenital heart disease who developed acute kidney injury after cardiac surgery, administration of iodinated contrast media for cardiac catheterization, and a combination of nephrotoxic drugs.

CASE REPORT

A term neonate without a prenatal diagnosis of congenital heart disease and with a good postnatal transition was transferred at 13 days of life to the MS Curie Emergency Hospital for Children, Newborn Intensive Care Unit, from a regional hospital where he was admitted at 10 days of life with severe general status, respiratory distress, cyanosis, and arterial hypotension. The cardiac ultrasound detected critical aortic valve stenosis, hypoplastic descending aorta, acute heart failure, and pulmonary hypertension. The patient was intubated and mechanically ventilated and received antibiotherapy (meropenem, vancomycin, and colistin), inotropic and vasoactive support (epinephrine, norepinephrine, dopamine, and milrinone), and diuretic support (furosemide, aminophylline, and ethacrynic acid). A balloon aortic valvuloplasty was performed several hours after admission, but after two days the patient required reintervention by open heart surgery due to relapsing severe aortic stenosis. He developed oligo-anuria, generalized edema, and altered renal function tests on the second postoperative and fourth day post-contrast media administration. Continuous renal replacement therapy was initiated for 75 h, leading to almost instant improvement in blood pressure, then diuresis and creatinine levels. The patient required long-term treatment for heart, respiratory, and liver failure. He was discharged at almost four months of age with normal renal function tests, blood pressure, and good urine output without diuretic support. The literature review indicates that contrast-associated acute kidney injury (CA-AKI) requiring continuous renal replacement therapy is rare.

CONCLUSIONS

Our current case proves that iodinated contrast media administration in a neonate with concomitant insults, such as cardiac surgery for a specific pathology, aortic stenosis, coarctation, arch stenosis, arterial hypotension, and administration of nephrotoxic drugs, may lead to severe kidney injury.

Oxygen delivery in pediatric cardiac surgery and its association with acute kidney injury using machine learning

OBJECTIVE

Acute kidney injury (AKI) after pediatric cardiac surgery with cardiopulmonary bypass (CPB) is a frequently reported complication. In this study we aimed to determine the oxygen delivery indexed to body surface area (Do2i) threshold associated with postoperative AKI in pediatric patients during CPB, and whether it remains clinically important in the context of other known independent risk factors.

METHODS

A single-institution, retrospective study, encompassing 396 pediatric patients, who underwent heart surgery between April 2019 and April 2021 was undertaken. Time spent below Do2i thresholds were compared to determine the critical value for all stages of AKI occurring within 48 hours of surgery. Do2i threshold was then included in a classification analysis with known risk factors including nephrotoxic drug usage, surgical complexity, intraoperative data, comorbidities and ventricular function data, and vasoactive inotrope requirement to determine Do2i predictive importance.

RESULTS

Logistic regression models showed cumulative time spent below a Do2i value of 350 mL/min/m2 was associated with AKI. Random forest models, incorporating established risk factors, showed Do2i threshold still maintained predictive importance. Patients who developed post-CPB AKI were younger, had longer CPB and ischemic times, and required higher inotrope support postsurgery.

CONCLUSIONS

The present data support previous findings that Do2i during CPB is an independent risk factor for AKI development in pediatric patients. Furthermore, the data support previous suggestions of a higher threshold value in children compared with that in adults and indicate that adjustments in Do2i management might reduce incidence of postoperative AKI in the pediatric cardiac surgery population.

Potential of Urine Biomarkers CHI3L1, NGAL, TIMP-2, IGFBP7, and Combinations as Complementary Diagnostic Tools for Acute Kidney Injury after Pediatric Cardiac Surgery: A Prospective Cohort Study

Acute kidney injury (AKI) is common after pediatric cardiac surgery (CS). Several urine biomarkers have been validated to detect AKI earlier. The objective of this study was to evaluate urine CHI3L1, NGAL, TIMP-2, IGFBP7, and NephroCheck® as predictors for AKI ≥ 1 in pediatric CS after 48 h and AKI ≥ 2 after 12 h. Pediatric patients (age < 18 year; body weight ≥ 2 kg) requiring CS were prospectively included. Urine CHI3L1, NGAL, TIMP-2, IGFBP7, and NephroCheck® were measured during surgery and intensive care unit (ICU) stay and corrected for urine dilution. One hundred and one pediatric patients were included. AKI ≥ 1 within 48 h after ICU admission occurred in 62.4% and AKI ≥ 2 within 12 h in 30.7%. All damage biomarkers predicted AKI ≥ 1 within 48 h after ICU admission, when corrected for urine dilution: CHI3L1 (AUC-ROC: 0.642 (95% CI, 0.535–0.741)), NGAL (0.765 (0.664–0.848)), TIMP-2 (0.778 (0.662–0.868)), IGFBP7 (0.796 (0.682–0.883)), NephroCheck® (0.734 (0.614–0.832)). Similarly, AKI ≥ 2 within 12 h was predicted by all damage biomarkers when corrected for urine dilution: uCHI3L1 (AUC-ROC: 0.686 (95% CI, 0.580–0.780)), NGAL (0.714 (0.609–0.804)), TIMP-2 (0.830 (0.722–0.909)), IGFBP7 (0.834 (0.725–0.912)), NephroCheck® (0.774 (0.658–0.865)). After pediatric cardiac surgery, the damage biomarkers urine CHI3L1, NGAL, TIMP-2, IGFBP7, and NephroCheck® reliably predict AKI after correction for urine dilution.

Del Nido cardioplegia for myocardial protection in adult cardiac surgery: a systematic review and update meta-analysis

OBJECTIVE

Although the application of del Nido cardioplegia solution (DNC) in adult cardiac surgery is accumulating, the feasibility and safety of this myocardial protection strategy in adults remains controversial. We aimed to update our previous meta-analysis to determine the myocardial protective effect of DNC versus conventional cardioplegia (CC) in adult cardiac surgery.

METHODS

A comprehensive literature search was performed using PubMed, EMBASE, the Cochrane Library, and International Clinical Trials Registry Platform databases through November 2020.

RESULTS

Thirty-seven observational studies and four randomized controlled trials (RCTs) including 21,779 patients were identified. The DNC group was associated with decreased postoperative cardiac enzymes [troponin T (cTnT) and creatine kinase-MB (CK-MB)] [standardized mean differences (SMD): -0.59, 95% confidence interval (CI): -0.99 to -0.19, p = 0.004], cardiopulmonary bypass (CPB) time (MD: -9.31, 95% CI: -13.10 to -5.51, p < 0.00001), aortic cross-clamp (ACC) time (MD: -7.20, 95% CI: -10.31 to -4.09, p < 0.00001), and cardioplegia volume (SMD: -1.95, 95% CI: -2.46 to -1.44, p < 0.00001). Intraoperative defibrillation requirement was less in the DNC group [relative risk (RR): 0.50, 95% CI: 0.33 to 0.75, p = 0.0007]. The pooled analysis revealed no significant difference in operative mortality among the patients assigned to DNC and those undergoing CC.

CONCLUSION

In adult cardiac surgery, compared to CC, myocardial protection used with DNC yield similar or better short-term clinical outcomes. More high-quality trials and RCTs reflecting long-term follow-up morbidity and mortality are required in the future to confirm these findings.

Acute Kidney Injury Predictors and Outcomes after Cardiac Surgery in Children with Congenital Heart Disease: An Observational Cohort Study

Acute Kidney Injury (AKI) commonly complicates cardiac surgery in children with congenital heart disease (CHD). In this study we assessed incidence, risk factors, and outcomes of postoperative AKI, while testing the hypothesis that, depending on the underlying diagnosis, there would be significant differences in AKI incidence among different diagnostic groups. We conducted an observational cohort study of children with CHD undergoing cardiac surgery in a single tertiary center between January 2019 and August 2021 (n = 362). Kidney Disease Improving Global Outcome (KDIGO) criteria were used to determine the incidence of postoperative AKI. Diagnosis was incorporated into multivariate models using an anatomic-based CHD classification system. Overall survival was estimated using Kaplan−Meier curves. Log-rank test and adjusted Cox proportional hazard modelling were used to test for differences in survival distributions and determine AKI effect on survival function, respectively. AKI occurred in 70 (19.3%), with 21.4% in-hospital mortality for AKI group. Younger age, lower weight, longer cardiopulmonary bypass time, preoperative mechanical ventilation and diagnostic category were associated with postoperative AKI. Resolution rate was 92.7% prior to hospital discharge for survivors. AKI was associated with longer duration of mechanical ventilation, ICU and hospital length of stay. AKI patients had significantly higher probability of all-cause mortality postoperatively when compared to the non-AKI group (log-rank test, p < 0.001). Adjusted hazard ratio for AKI versus non-AKI group was 11.08 (95% CI 2.45−50.01; p = 0.002). Diagnostic category was associated with cardiac surgery-related AKI in children with CHD, a finding supporting the development of lesion specific models for risk stratification. Postoperative AKI had detrimental impact on clinical outcomes and was associated with decreased survival to hospital discharge.

Cardiorenal syndrome in the pediatric population: A systematic review

The concept of cardiorenal syndrome (CRS) is derived from the crosstalk between the heart and kidneys in pathological conditions. Despite the rising importance of CRS, there is a paucity of information on the understanding of its pathophysiology and management, increasing both morbidity and mortality for patients. This review summarizes the existing conceptual pathophysiology of different types of CRS and delves into the associated therapeutic modalities with a focus on pediatric cases. Prospective or retrospective observational studies, comparative studies, case reports, case-control, and cross-sectional studies that include pediatric patients with CRS were included in this review. Literature was searched using PubMed, EMBASE, and Google Scholar with keywords including "cardio-renal syndrome, type," "reno-cardio syndrome," "children," "acute kidney injury," and "acute decompensated heart failure" from January 2000 to January 2021. A total of 14 pediatric studies were ultimately included and analyzed, comprising a combined population of 3608 children of which 32% had CRS. Of the 14 studies, 57% were based on type 1 CRS, 14% on types 2 and 3 CRS, and 7% were on types 4 and 5 CRS. The majority of included studies were prospective cohort, although a wide spectrum was observed in terms of patient age, comorbidities, etiologies, and treatment strategies. Commonly observed comorbidities in CRS type 1 were hematologic, oncologic, cardiology-related side effects, muscular dystrophy, and pneumonia/bronchiolitis. CRS, particularly type 1, is prevalent in children and has a significant risk of mortality. The current treatment regimen primarily involves diuretics, extracorporeal fluid removal, and treatment of underlying etiologies and comorbidities.

Evaluation of postoperative renal functions and its effect on body perfusion in patients with double aortic cannulation

BACKGROUND

The optimal visceral preservation method during aortic arch reconstruction is still controversial. It has been thought that double aortic cannulation is effective. Herein, it was aimed to evaluate this technique in providing distal perfusion.

METHODS

A total of 74 patients who underwent arch reconstruction between 2011 and 2019 were included. Patients were grouped according to ventricular physiology and cannulation strategies. Group 1 were univentricle patients, and all had double aortic cannulation. Group 2 were biventricular patients. Group 2A double aortic cannulation-done and Group 2B non-double aortic cannulation were included. Lactate, urea, creatinine values, renal functions, and need for peritoneal dialysis of patients were evaluated.

RESULTS

There were no complications observed due to descending aortic cannulation in any of the patients. A delayed sternal closure and the need for peritoneal dialysis were more common in the Group 1 (p < 0.01). The preoperative and postoperative 1st- and 2nd-day lactate, urea, and creatinine values in the Group 1 were higher (p < 0.05) when compared with the Group 2A and 2B. The same values were higher in Group 2A than the Group 2B (p < 0.05).

CONCLUSION

The positive effect of double aortic cannulation on renal dysfunction could not be demonstrated. This may be associated with a <1 month of age, low weight, complex surgical procedure, and high preoperative lactate, urea, and creatinine values in patients with double aortic cannulation.

Biomarkers of acute kidney injury after pediatric cardiac surgery: a meta-analysis of diagnostic test accuracy

Acute kidney injury (AKI) occurs frequently after cardiac surgery in children. Although current diagnostic criteria rely on serum creatinine and urine output, changes occur only after considerable loss of kidney function. This meta-analysis aimed to synthesize the knowledge on novel biomarkers and compare their ability to predict AKI. PubMed/MEDLINE, Embase, Scopus, and reference lists were searched for relevant studies published by March 2021. Diagnostic accuracy parameters were extracted and analyzed using hierarchical summary receiver operating characteristic (HSROC) method. Pooled estimates of the area under the curve (AUC) were calculated using conventional random-effects meta-analysis. Fifty-six articles investigating 49 biomarkers in 8617 participants fulfilled our eligibility criteria. Data from 37 studies were available for meta-analysis. Of the 10 biomarkers suitable for HSROC analysis, urinary neutrophil gelatinase-associated lipocalin (uNGAL) to creatinine (Cr) ratio yielded the highest diagnostic odds ratio (91.0, 95% CI 90.1-91.9), with a sensitivity of 91.3% (95% CI 91.2-91.3%) and a specificity of 89.7% (95% CI 89.6-89.7%). These results were confirmed in pooled AUC analysis, as uNGAL-to-Cr ratio and uNGAL were the only elaborately studied biomarkers (> 5 observations) with pooled AUCs ≥ 0.800. Liver fatty acid-binding protein (L-FABP), serum cystatin C (sCysC), serum NGAL (sNGAL), and interleukin-18 (IL-18) all had AUCs ≥ 0.700.

CONCLUSION

A variety of biomarkers have been proposed as predictors of cardiac surgery-associated AKI in children, of which uNGAL was the most prominent with excellent diagnostic qualities. However, more consolidatory evidence will be required before these novel biomarkers may eventually help realize precision medicine in AKI management.

WHAT IS KNOWN

• Acute kidney injury (AKI) occurs in about 30-60% of children undergoing cardiac surgery and is associated with increased in-hospital mortality and adverse short-term outcomes. However, in current clinical practice, AKI definitions and detection often rely on changes in serum creatinine and urine output, which are late and insensitive markers of kidney injury. • Although various novel biomarkers have been studied for the diagnosis of AKI in children after cardiac surgery, it remains unclear how these compare to one another in terms of diagnostic accuracy.

WHAT IS NEW

• Pooled analyses suggest that for the diagnosis of AKI in children who underwent cardiac surgery, NGAL is the most accurate among the most frequently studied biomarkers. • A number of other promising biomarkers have been reported, although they will require further research into their diagnostic accuracy and clinical applicability.

Early post-operative PV-ACO2/CA-VO2 predicts subsequent acute kidney injury after complete repair of tetralogy of Fallot

BACKGROUND

Acute kidney injury is a severe complication following complete repair of tetralogy of Fallot. Anaerobic metabolism is believed to contribute to the development of acute kidney injury. The ratio of central venous to arterial carbon dioxide tension to arterio-venous oxygen content (PV-ACO2/CA-VO2) has been proposed as a surrogate for respiratory quotient and an indicator of tissue oxygenation. We hypothesised that a small increase of PV-ACO2/CA-VO2 might have superior discrimination ability in subsequent acute kidney injury prediction.

METHODS

This study is retrospective and single-centre design study. The study population consisted of 61 children with tetralogy of Fallot that underwent a complete surgical repair between July 2017 and January 2021. Baseline characteristics and intra-operative parameters were collected through a retrospective chart review. PV-ACO2/CA-VO2 was collected within 12 hours of surgical completion. Acute kidney injury was defined according to the criteria established by the Kidney Disease: Improving Global Outcomes group. Univariate and logistic regression analyses were performed to determine risk factors for acute kidney injury.

RESULTS

Of the 61 patients, 20 (32.8%) developed acute kidney injury. Multivariate logistic analyses showed that age, height, haematocrit, and Pv-aCO2/Ca-vO2 were independently associated with the development of acute kidney injury. The addition of Pv-aCO2/Ca-vO2 to the model significantly increased model discrimination [AUROC 0.939 (95% CI 0.894-0.984) and AUROC 0.922 (95% CI 0.869-0.975), respectively].

CONCLUSIONS

The increase of PV-ACO2/CA-VO2 could improve the predictive ability for subsequent development of acute kidney injury in children with tetralogy of Fallot.

Postoperative Acute Kidney Injury in Williams Syndrome Compared With Matched Controls

OBJECTIVES

Cardiovascular manifestations occur in over 80% of Williams syndrome (WS) patients and are the leading cause of morbidity and mortality. One-third of patients require cardiovascular surgery. Renal artery stenosis (RAS) is common in WS. No studies have assessed postoperative cardiac surgery-related acute kidney injury (CS-AKI) in WS. Our objectives were to assess if WS patients have higher risk of CS-AKI postoperatively than matched controls and if RAS could contribute to CS-AKI.

DESIGN

This was a retrospective study of all patients with WS who underwent cardiac surgery at our center from 2010 to 2020. The WS study cohort was compared with a group of controls matched for age, sex, weight, and surgical procedure.

SETTING

Patients underwent cardiac surgery and postoperative care at Lucile Packard Children's Hospital Stanford.

PATIENTS

There were 27 WS patients and 43 controls (31% vs 42% female; p = 0.36). Median age was 1.8 years (interquartile range [IQR], 0.7-3.8 yr) for WS and 1.7 years (IQR, 0.8-3.1 yr) for controls.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Postoperative hemodynamics, vasopressor, total volume input, diuretic administration, and urine output were collected in the first 72 hours. Laboratory studies were collected at 8-hour intervals. Multivariable analysis identified predictors of CS-AKI.Controlled for renal perfusion pressure (RPP) and vasoactive inotrope score (VIS), compared with controls, the odds ratio (OR) of CS-AKI in WS was 4.2 (95% CI, 1.1-16; p = 0.034). Higher RPP at postoperative hours 9-16 was associated with decreased OR of CS-AKI (0.88 [0.8-0.96]; p = 0.004). Increased VIS at hour 6 was associated with an increased OR of CS-AKI (1.47 [1.14-1.9]; p = 0.003). Younger age was associated with an increased OR of CS-AKI (1.9 [1.13-3.17]; p = 0.015).

CONCLUSIONS

The OR of CS-AKI is increased in pediatric patients with WS compared with controls. CS-AKI was associated with VIS at the sixth postoperative hour. Increases in RPP and mean arterial pressure were associated with decreased odds of CS-AKI.

Effect of intraoperative theophylline use on acute kidney injury in paediatric cardiac surgery

BACKGROUND

This study aimed to examine the effects of theophylline use in preventing renal dysfunction in patients undergoing CHD surgery.

METHODS

A total of 94 patients aged 1-60 months were included in the study. Patients in the theophylline group were enrolled according to a pre-defined protocol for treatment administration, while controls were selected retrospectively from patients without theophylline treatment during the same period - who were matched according to critical baseline characteristics.

RESULTS

The incidence of acute kidney injury was similar between the two groups (p = 1.000). Higher urinary output and lower fluid balance were found intraoperatively and also postoperatively in the theophylline group (all, p < 0.050). Postoperative decrease in urinary output and estimated glomerular filtration rate were higher in the theophylline group (p < 0.050). Lower postoperative urea and creatinine levels were shown in theophylline recipients (p < 0.050). Urea levels increased significantly in the non-theophylline group during surgery (p < 0.001), and no significant change was observed in theophylline group (p = 0.136). Postoperative increase in creatinine and lactate levels was demonstrated in theophylline group (p < 0.050), and lactate levels were higher in the non-theophylline group during and after cardiopulmonary bypass (p = 0.010). Multiple linear regression analysis revealed less reduction in estimated glomerular filtration rate with higher age and in the presence of theophylline use (p < 0.050).

CONCLUSION

Although we demonstrated a similar incidence of acute kidney injury in the both groups, we revealed an important decrease in serum creatinine, urea and lactate levels, accompanied by improved estimated glomerular filtration rate, increased urine output and decreased fluid overload, with theophylline treatment, suggesting that renal functions significantly improved with the use of theophylline.

Risk Factors and Consequences of Acute Kidney Injury After Noncardiac Surgery in Children

BACKGROUND

Postoperative acute kidney injury (AKI) is a serious complication that is associated with prolonged hospital stay, high risk of short-term postsurgical mortality, need for dialysis, and possible progression to chronic kidney disease. To date, very little data exist on the risk of postoperative AKI among children undergoing noncardiac surgical procedures. We used data from a large multicenter cohort to determine the factors associated with AKI among children who underwent inpatient noncardiac surgical procedures and its impact on the postoperative course.

METHODS

We utilized the National Surgical Quality Improvement Program Pediatric participant user files to identify a cohort of children who underwent inpatient surgery between 2012 and 2018 (n = 257,439). We randomly divided the study population into a derivation cohort of 193,082 (75%) and a validation cohort of 64,357 (25%), and constructed a multivariable logistic regression model to identify independent risk factors for AKI. We defined AKI as the occurrence of either acute renal failure or progressive renal insufficiency within the 30 days after surgery.

RESULTS

The overall rate of postoperative AKI was 0.10% (95% confidence interval [CI], 0.09-0.11). In a multivariable model, operating times longer than 140 minutes, preexisting hematologic disorder, and preoperative sepsis were the strongest independent predictors of AKI. Other independent risk factors for AKI were American Society of Anesthesiologists (ASA) physical status ≥III, preoperative inotropic support, gastrointestinal disease, ventilator dependency, and corticosteroid use. The 30-day mortality rate was 10.1% in children who developed AKI and 0.19% in their counterparts without AKI (P < .001). Children who developed AKI were more likely to require an extended hospital stay (≥75th percentile of the study cohort) relative to their peers without AKI (77.4% vs 21.0%; P < .001).

CONCLUSIONS

Independent preoperative risk factors for AKI in children undergoing inpatient noncardiac surgery were hematologic disorder, preoperative sepsis, ASA physical status ≥III, inotropic support, gastrointestinal disease, ventilator dependency, and steroid use. Children with AKI were 10 times more likely to die and nearly 3 times more likely to require an extended hospital stay, relative to their peers without AKI.

The comparison of three different acute kidney injury classification systems after congenital heart surgery

BACKGROUND

We aimed to compare the frequency of acute kidney injury (AKI) and its effects on mortality and morbidity with different classification systems in pediatric patients who had surgery under cardiopulmonary bypass for congenital heart disease.

METHODS

This study included children younger than 18 years old who were followed up in the pediatric cardiac intensive care unit between September 1 and December 1, 2020, after congenital heart surgery with cardiopulmonary bypass. Each case was categorized postoperatively in terms of AKI using Pediatric-Modified Risk, Injury, Failure, Loss, and End-Stage (pRIFLE), Acute Kidney Injury Network (AKIN), and Kidney Disease: Improving Global Outcomes (KDIGO). Hospital mortality (developed within the first 30 days postoperatively) and morbidity (longer than 7 days intensive care unit stay) were compared by three model classes. Results were evaluated statistically.

RESULTS

One hundred patients were included in the study. The median age was 3 months (1 day-180 months). Acute kidney injury was diagnosed in 49% of the cases according to the pRIFLE classification. It was diagnosed in 31% of the patients by AKIN classification. It was diagnosed in 41% of the patients with the KDIGO criteria. Morbidity was observed in 25% (n = 25) of all cases. The morbidity predictor was 0.800 for pRIFLE, 0.747 for AKIN and 0.853 for KDIGO by receiver operating characteristics analysis. All three categories predicted morbidity significantly (P < 0.001). Mortality was 10% (n = 10) for all groups. The mortality predictor was 0.783 for pRIFLE, 0.717 for AKIN and 0.794 for KDIGO by receiver operating characteristics analysis, and all three categories predicted mortality significantly (P < 0.001).

CONCLUSIONS

Regardless of the three methods used, AKI was commonly detected in pediatric patients undergoing congenital heart surgery. pRIFLE classification diagnosed more patients with AKI than AKIN and KDIGO. The KDIGO and pRIFLE classifications were better in predicting hospital mortality.

Acute Kidney Injury After Neonatal Aortic Arch Surgery: Deep Hypothermic Circulatory Arrest Versus Moderate Hypothermia With Distal Aortic Perfusion

BACKGROUND

Acute kidney injury (AKI) is a common complication observed after neonatal aortic arch repair. We studied its incidence after procedures carried out using deep hypothermic circulatory arrest (DHCA) versus moderate hypothermia with distal aortic perfusion (MHDP), usually through the common femoral artery. In both groups, continuous regional cerebral perfusion (RCP) was used during the time required for aortic arch repair.

METHODS

A total of 125 neonates underwent aortic arch repair. Between 2007 and 2012, DHCA with RCP was used in 51 neonates. From 2013 to 2019, MHDP with RCP was performed on 74 newborns. Operative complexity was similar in both periods. Acute kidney injury was defined as a significant elevation of serum creatinine and was classified according to the neonatal modified n-KDIGO (neonatal Kidney Disease: Improving Global Outcomes) stages 1 to 3 (Kidney Disease Improving: Global Outcomes).

RESULTS

Acute kidney injury was observed in a total of 68 patients (68/125: 54.4%). In the majority (44/68: 64.7%), n-KDIGO stage 1 occurred. Stage 2 (n = 14) and stage 3 (n = 10) were observed more frequently after DHCA versus MHDP: 29.4% (15/51) versus 12.2% (9/74), P = .02. At cardiopulmonary bypass end, lactate levels were significantly higher (P = .001) after DHCA: 3.4 (2.9-4.3) mmol/L compared to 2.7 (2.3-3.7) mmol/L after MHDP. Early mortality was 12% (15/125) in the entire cohort. It was 17.6% (9/51) after DHCA versus 8.1% (6/74) after MHDP, however not statistically significant (P = .16).

CONCLUSION

Mild (stage 1) AKI occurred frequently after neonatal aortic arch repair. The use of MHDP was associated with a significantly lower incidence of moderate (stage 2) and severe (stage 3) AKI forms.

Higher total ultrafiltration volume during cardiopulmonary bypass-assisted infant cardiac surgery is associated with acute kidney injury and fluid overload

BACKGROUND

Ultrafiltration (UF) is used for fluid removal during and after infant cardiopulmonary bypass (CPB) surgery to reduce fluid overload. Excessive UF may have the opposite of its intended effect, resulting in acute kidney injury (AKI), oliganuria, and fluid retention.

METHODS

This is a single-center, retrospective review of infants treated with conventional and/or modified UF during CPB surgery. UF volume was indexed to weight. AKI was defined using serum creatinine "Kidney Disease Improving Global Outcome (KDIGO)" criteria. Fluid balance was defined according to: [Formula: see text]. Peak fluid overload was determined on postoperative day 3. Multivariable logistic regression adjusted for multiple covariates was used to explore associations with UF, AKI, and fluid overload.

RESULTS

Five hundred thirty subjects < 1 year of age underwent CPB-assisted congenital heart surgery with UF. Sixty-four (12%) developed postoperative AKI. On multivariable regression, higher indexed total UF volume was associated with increased AKI risk (OR 1.11, 95% CI=1.04-1.19, p = 0.003). UF volume > 119.9 mL/kg did not reduce peak fluid overload. Subjects with AKI took longer to reach a negative fluid balance (2 vs. 3 days, p = 0.04). Those with more complex surgery were at highest AKI risk (STAT 3 [25-75 percentile: 3-4] in AKI group versus STAT 3 [25-75 percentile: 2-4] in non-AKI group, p = 0.05). AKI was reduced in subjects undergoing more complex surgery and treated with UF volume < 119.9 mL/kg.

CONCLUSIONS

Judicious use of UF in more complex congenital cardiac surgery reduces the risk of AKI.

Association of pediatric cardiac surgery-associated acute kidney injury with post-discharge healthcare utilization, mortality and kidney outcomes

BACKGROUND

Acute kidney Injury (AKI) in children undergoing cardiac surgery (CS) is strongly associated with hospital morbidity. Post-discharge CS AKI outcomes are less clear. We evaluated associations between AKI and post-discharge (a) healthcare utilization, (b) chronic kidney disease (CKD) or hypertension and (c) mortality.

METHODS

This is a retrospective two-centre cohort study of children surviving to hospital discharge after CS. Primary exposures were post-operative ≥Stage 1 AKI and ≥Stage 2 AKI defined by Kidney Disease Impoving Global Outcomes. Association of AKI with time to outcomes was determined using multivariable Cox-Proportional Hazards analysis.

RESULTS

Of 350 participants included (age 3.1 (4.5) years), 180 [51.4%] developed AKI and 60 [17.1%] developed ≥Stage 2 AKI. Twenty-eight (9%) participants developed CKD or hypertension (composite outcome), and 17 (5%) died within 5 years of discharge. Post-operative ≥Stage 1 and ≥Stage 2 AKI were not associated with post-discharge hospitalizations, emergency room (ER) visits, physician visits or CKD or hypertension in adjusted analyses. A trend was observed between ≥Stage 2 AKI and mortality but was not statistically significant. In unadjusted stratified analyses, AKI was associated with post-discharge hospitalizations in children with RACHS-1 score ≥3, complex chronic disease classification and children living in urban areas.

CONCLUSIONS

Post-CS AKI is not associated with post-discharge healthcare utilization, death and CKD or hypertension, though it may be associated with healthcare utilization in more complex paediatric CS children. Studies should aim to better understand post-CS healthcare utilization patterns and non-AKI risk factors for CKD, hypertension and mortality, to reduce adverse long-term outcomes after CS.

Severe postoperative hyperbilirubinemia in congenital heart disease

PURPOSE

The purpose of our present study was to explore the characteristics and outcomes of congenital heart disease (CHD) patients with severe postoperative hyperbilirubinemia.

METHODS

All patients who underwent cardiopulmonary bypass surgical treatment for CHD and had severe postoperative hyperbilirubinemia (total bilirubin [TB] ≥85.5 μmol/L) in our center between January 2015 and December 2018 were retrospectively screened. Univariate and multivariate analyses were employed to identify risk factors for the study endpoints, including postoperative acute kidney injury (AKI), in-hospital mortality, and long-term mortality.

RESULTS

After screening, 86 patients were included in our present study. In-hospital mortality was 10.9%. Fifty-one (59.3%) patients experienced AKI, and four (4.7%) patients received continuous renal replacement therapy. Multivariate analysis identified that the peak TB concentration (P = 0.002) and duration of mechanical ventilation (P = 0.008) were independent risk factors for in-hospital mortality, and stage 3 AKI was an independent risk factor for long-term mortality. The optimal cutoff value for peak TB concentration was 125.9 μmol/L. Patients with a postoperative TB level ≥125.9 μmol/L had worse long-term survival.

CONCLUSION

Hyperbilirubinemia was a common complication after CHD surgery. CHD patients with severe postoperative hyperbilirubinemia ≥125.9 μmol/L and AKI had a higher risk of mortality.

Renal tissue desaturation and acute kidney injury in infant cardiac surgery: a prospective propensity score-matched cohort study

BACKGROUND

Previous studies on the association between renal tissue desaturation and acute kidney injury (AKI) in infant cardiac surgery are limited by small sample sizes and inconsistent results. This prospective study aimed to determine the association between renal desaturation and AKI in infants undergoing surgical repair of an isolated ventricular septal defect (VSD).

METHODS

Infants undergoing VSD repair involving cardiopulmonary bypass participated in this prospective cohort study. The exposure of interest was renal tissue desaturation, defined as at least 20% decrease in saturation from baseline for at least 60 consecutive seconds. Intraoperative care was not guided by renal oxygenation, as the anaesthesiologists were blinded to the monitor. The outcome was AKI arising within postoperative Days 1-3. The primary analysis was based on propensity score-matched infants with and without intraoperative renal desaturation.

RESULTS

Intraoperative renal desaturation was detected in 38 of 242 infants using near-infrared spectroscopy. This group of infants was matched with 114 infants without intraoperative renal saturation after propensity score matching. Acute kidney injury occurred in 47% (18/38) and 27% (31/114) of infants with or without renal desaturation, respectively. Infants with renal desaturation had higher odds of developing AKI than infants without renal desaturation based on conditional logistic regression (odds ratio 2.79; 95% confidence interval: 1.21-6.44; P=0.016). The cumulative time of renal desaturation correlated moderately with the ratio of postoperative peak creatinine to preoperative baseline creatinine (r=0.51; P<0.001).

CONCLUSIONS

Intraoperative renal desaturation is associated with increased odds of developing AKI after surgical repair of an isolated VSD involving cardiopulmonary bypass in infants.

CLINICAL TRIAL REGISTRATION

NCT03941015.

Contrast media exposure in the perioperative period confers no additional risk of acute kidney injury in infants and young children undergoing cardiac surgery with cardiopulmonary bypass

BACKGROUND

Recently, there has been an interest in the temporal relationship between contrast exposure (CM) and cardiac surgery suggesting that a "double hit" on the kidney function in close succession increases the risk of acute kidney injury (AKI) after cardiac surgery. However, data from young children is limited. The purpose of this study was to retrospectively evaluate the effects of preoperative CM exposure on postoperative AKI in infant and young children patients and to further analyze the influence of exposure time interval.

METHODS

Patients (age ≤ 3 years) who underwent diagnostic imaging within 14 days before on-pump cardiac surgery between 1 May 2017 and 31 May 2018 in Fuwai Hospital, Beijing, were analyzed. Kidney outcome was assessed according to Kidney Disease: Improving Global Outcomes creatinine-based criteria.

RESULTS

One thousand four hundred pediatric patients (192 CM and 1,248 non-CM) were identified. Postoperative AKI occurred in 57 (29.7%) of the 192 patients who were exposed to CM. Following propensity score adjustment, no difference in risk for AKI was observed between the CM and non-CM groups (RR 1.142, 95% CI 0.916-1.424; P = 0.264). Multivariable logistic regression of the CM group indicated that independent predictors of postoperative AKI were lower weight, lower preoperative creatinine level, and longer CPB duration. Time interval between CM exposure and on-pump cardiac surgery was not significantly associated with increased risk of AKI (OR 0.853, 95% CI 0.265~2.747; P = 0.790).

CONCLUSIONS

For pediatric patients who are soon to undergo on-pump cardiac procedures, there appears to be no need to hesitate in performing the diagnostic imaging investigations requiring CM, or delay CPB after CM exposure. These patients may benefit from increased diagnostic utility without increasing their risk of postoperative AKI.

Preoperative Anemia and Outcomes After Corrective Surgery in Neonates With Dextro-Transposition of the Great Arteries

OBJECTIVES

The authors aimed to assess whether untreated preoperative anemia was associated with increased risk for adverse outcomes after the arterial switch operation in neonates with dextro-transposition of the great arteries (d-TGA).

DESIGN

Retrospective cohort study.

SETTING

Single cardiac surgery center.

PARTICIPANTS

Eighty-two newborns with d-TGA.

INTERVENTIONS

The authors categorized the cohort into the following two groups: the infants with preoperative anemia group (defined as a hematocrit <0.40 L/L) and the control group.

MEASUREMENTS AND MAIN RESULTS

Preoperative anemia was diagnosed in 21 (25.6%) infants. Anemic infants received intraoperative red blood cell transfusions significantly more often than controls (81.0% v 34.4%, p < 0.001). No differences were observed in the incidence of adverse events, duration of hospitalization (median 27 days v 26 days, p = 0.881), and mortality (0% v 4.9%, p = 0.566). Postnatal hematocrit was the only variable independently associated with preoperative anemia in multivariate logistic regression analysis (unit odds ratio, 0.832; 95% confidence interval, 0.743-0.931; p = 0.001).

CONCLUSIONS

Untreated preoperative anemia was not associated with adverse outcomes in neonates undergoing reparative surgery for d-TGA.

Cardiorenal Syndrome

Cardiorenal syndrome (CRS) describes a specific acute and chronic clinical picture in which the heart or the kidney are primarily dysfunctioning and secondarily affect each other. CRS is divided into five classes: acute and chronic CRS, acute and chronic renocardiac syndromes, and secondary dysfunction of heart and kidneys. This article specifically details the classification and the epidemiology, some risk factors, and the pathophysiology of CRS. Some emerging aspects of CRS are also discussed, such as CRS in patients with end-stage heart failure, with mechanical ventricular assistance, and after heart transplantation. Finally, some aspects of pediatric CRS are detailed.

Nadir Oxygen Delivery During Pediatric Bypass as a Predictor of Acute Kidney Injury

BACKGROUND

Cardiac surgery-associated acute kidney injury (CS-AKI) is common in infants and is associated with negative outcomes. Nadir indexed oxygen delivery (DO₂i) during cardiopulmonary bypass (CPB) is associated with the occurrence of postoperative CS-AKI, with critical thresholds for DO₂i reported to be 262 to 300 mL/min/m² in adults. However, given that infants have a higher metabolic rate and oxygen demand, the critical DO₂i in infants is not comparable with existing adult standards. This study aimed to explore the critical DO₂i threshold during pediatric CPB.

METHODS

Between March 2019 and April 2020, 106 consecutive infants undergoing cardiac surgery with CPB were admitted to this prospective observational cohort study. The DO₂i levels of each patient were monitored during CPB. Pre- and intraoperative factors were tested for independent association with CS-AKI. The postoperative outcomes of patients with or without CS-AKI were compared.

RESULTS

In our patient population (n = 83), we identified 25 patients (38.5%) with postoperative CS-AKI. Multivariate analysis revealed 2 independent risk factors for onset of CS-AKI: CPB duration and nadir DO₂i. The lowest suitable DO₂i during CPB in the present population was 353 mL/min/m² (sensitivity, 65.6%; specificity, 74.5%). CS-AKI during pediatric CPB remained significantly associated with an increased morbidity, related mainly to a postoperative low cardiac output syndrome, but not to mortality.

CONCLUSIONS

The lowest suitable DO₂i during CPB in the infant population undergoing cardiac surgery was 353 mL/min/m². Below this threshold, there was a high probability of inducing CS-AKI.

Preoperative Hemoglobin Level, Oxygen Saturation and Postoperative Outcomes in Children With Cyanotic Congenital Heart Disease: A Propensity-Score Matching Analysis

BACKGROUND

The optimal preoperative hemoglobin (Hb) level is difficult to define in children with cyanotic congenital heart disease (CHD) due to hypoxemia-induced secondary erythrocytosis. This retrospective study integrated preoperative Hb and pulse oxygen saturation (SpO₂) using the product of Hb × SpO₂ to predict postoperative outcomes in children with cyanotic CHD.

PATIENTS AND METHODS

Children aged <18 years undergoing cardiac surgery with cyanotic CHD were included. The cutoff value of Hb × SpO₂ was the age-adjusted lower limit of normal Hb (aaHb) in healthy children. The main outcomes were in-hospital death and the composite outcome of severe postoperative events. Multivariate logistic regression analysis and propensity score matching analysis were used to adjust for important confounders.

RESULTS

The presence of preoperative Hb × SpO₂ < aaHb was observed in 21.6% of cyanotic children (n = 777). Children with Hb × SpO₂ < aaHb had higher in-hospital mortality (12.5% vs. 4.6%, P < 0.001) and composite outcome incidence (69.6% vs. 32.3%, P < 0.001) than those with Hb × SpO₂ ≥ aaHb. After propensity score matching, 141 pairs of children were successfully matched. Multivariate analysis showed that preoperative Hb × SpO₂ < aaHb was significantly associated with the composite outcome in the entire population (odds ratio = 4.092, 95% confidence interval = 2.748-6.095, P < 0.001) and the matched cohorts (odds ratio = 2.277, 95% confidence interval = 1.366-3.795, P = 0.002).

CONCLUSION

Our results suggest that a preoperative Hb × SpO₂ value below the lower limit of normal hemoglobin is a prognostic factor in cyanotic children undergoing cardiac surgery and is a potential criterion to evaluate preoperative anemia in this population.

Acute Kidney Injury Post-cardiac Surgery in Infants and Children: A Single-Center Experience in a Developing Country

Introduction: The incidence of acute kidney injury (AKI) in pediatric patients following cardiac surgery varies between 15 and 64%, with a mortality rate of 10-89% among those requiring dialysis. This variation in the incidence and mortality of AKI across studies is probably due to the inconsistent definitions used for AKI. The purpose of this study is to present our experience with AKI post-cardiac surgery with emphasis on predisposing or aggravating factors. Patients and Methods: We evaluated the incidence of AKI using the KDIGO criteria in 150 infants and children undergoing cardiac surgeries between 2015 and 2017. Post-operatively, all patients were admitted to the pediatric intensive care unit (PICU) at a tertiary care center in a developing country. This is a retrospective chart review in which data collected included age, gender, type of heart disease, prior cardiac surgeries, RACHS-1 category, and pre- and post-operative creatinine levels. Neonates were not included in this study. Results: Six percent of the studied patients were below 1 year of age, 84% 1-10 years, and 10% 10-18 years. Fourteen patients (9.3%) developed AKI. Patients with cyanotic heart disease were more prone to develop AKI (78%) compared to those with non-cyanotic heart disease (44%). Children with AKI had a higher length of stay in PICU, 2.56 ± 1.44 vs. 4 ± 2.66 (p- 0.02). Serum lactic acid was higher in patients who developed AKI with a mean value of 6.8 ± 6.9 vs. 2.85 ± 1.55 mmol/l in the non-AKI group (p- 0.03). Lower hemoglobin levels and hyperlactic acidemia were significantly more prevalent in the AKI group. There were five deaths in this series (3.3%), and four of those (80%) were in the AKI group. Conclusion: Using the KDIGO criteria, the incidence of AKI in infants and children following cardiac surgery was 9.3%. This is slightly lower than in previously published studies where the range was between 15 and 64%. Children with cyanotic cardiac disease, hyperlactic acidemia, and anemia were more prone to developing AKI. Identifying patients at risk might help decrease the risk of post-operative AKI.

The association of acute kidney injury with hospital readmission and death after pediatric cardiac surgery

Background

Acute kidney injury (AKI) in children undergoing cardiac surgery (CS) is strongly associated with increased hospital mortality and length of stay. The association of AKI with postdischarge outcomes is unclear. We evaluated the association of AKI with all-cause readmissions and death within 30 days and 1 year of CS discharge.

Methods

This was a prospective, 3-center cohort study of children after CS with cardiopulmonary bypass. The primary exposures were postoperative ≥stage 1 AKI and ≥stage 2 AKI defined by Kidney Disease: Improving Global Outcomes AKI definition. Two separate outcomes were hospital readmission and death within 30 days and 1 year of discharge. Association of AKI with time to outcomes was determined using multivariable Cox-proportional hazards analysis. Age, The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery risk adjustment tool score ≥3, cardiopulmonary bypass >120 minutes, and cyanotic heart disease were evaluated as effect modifiers.

Results

Of 402 participants included (median age 1.8 years [interquartile range 0.4, 5.2]), 32 (8.0%) and 109 (27.1%) were readmitted; 7 (1.7%) and 9 (2.2%) died within 30 days and 1 year of CS, respectively. AKI was not associated with readmission at 30 days or 1 year postdischarge. ≥Stage 2 AKI (adjusted hazard ratio, 11.68 [1.88, 72.61]) was associated with mortality 30 days post-CS.

Conclusions

Postoperative AKI was not associated with readmission at 30 days and 1-year postdischarge. However, more severe AKI (≥stage 2) appears to be associated with increased morality risk at 30 days post-CS.

Effects of intraoperative dexmedetomidine on the incidence of acute kidney injury in pediatric cardiac surgery patients: A randomized controlled trial

BACKGROUND

Perioperative dexmedetomidine use has been reported to reduce the incidence of postoperative acute kidney injury after adult cardiac surgery. However, large-scale randomized controlled trials evaluating the effect of dexmedetomidine use on acute kidney injury in pediatric patients are lacking.

AIMS

We investigated whether intraoperative dexmedetomidine could reduce the incidence of acute kidney injury in pediatric cardiac surgery patients.

METHODS

In total, 141 pediatric patients were randomly assigned to dexmedetomidine or control groups. After anesthetic induction, patients in the dexmedetomidine group were administered 1 µg/kg of dexmedetomidine over 10 minutes and an additional 0.5 µg/kg/h of dexmedetomidine during surgery. Additionally, 1 µg/kg of dexmedetomidine was infused immediately after cardiopulmonary bypass was initiated. The incidence of acute kidney injury was defined following Kidney Disease Improving Global Outcomes guidelines.

RESULTS

The final analysis included 139 patients. The incidence of acute kidney injury did not differ between dexmedetomidine and control groups (16.9% vs 23.5%; odds ratio 0.661; 95% CI 0.285 to 1.525; P = .33). Similarly, neither the incidence of abnormal postoperative estimated glomerular filtration rate values (P = .96) nor the incidence of arrhythmia, mechanical ventilation duration, length of stay in the intensive care unit, and hospitalization differed between the two groups.

CONCLUSIONS

Intraoperative dexmedetomidine did not reduce acute kidney injury incidence in pediatric cardiac surgery patients.

Development of acute kidney injury following pediatric cardiac surgery

Acute kidney injury (AKI) in the pediatric population is a relatively common phenomenon. Specifically, AKI has been found in increasing numbers within the pediatric population following cardiac surgery, with up to 43% of pediatric patients developing AKI post-cardiac surgery. However, recent advances have allowed for the identification of risk factors. These can be divided into preoperative, intraoperative, and postoperative factors. Although the majority of pediatric patients developing AKI after cardiac surgery completely recover, this condition is associated with worse outcomes. These include fluid overload and increased mortality and result in longer hospital and intensive care unit stays. Detecting the presence of AKI has advanced; use of relatively novel biomarkers, including neutrophil gelatinase associated lipocalin, has shown promise in detecting more subtle changes in kidney function when compared to conventional methods. While a single, superior treatment has not been elucidated yet, novel functions of medications, including fenoldopam, theophylline and aminophylline, have been shown to have better outcomes for these patients. With the recent advances in identification of risk factors, outcomes, diagnosis, and management, the medical community can further explain the complexities of AKI in the pediatric population post-cardiac surgery.

The Epidemiology and Management of Pediatric AKI in Asia

Because of the lack of early recognition and referral, the incidence of pediatric acute kidney injury (AKI) in Asia still is underestimated. Although each diagnostic criteria has its own merits, the Kidney Disease Improving Global Outcomes classification now is widely accepted. In Asia, the spectrum of pediatric AKI is wide-ranging, from pediatric AKI in highly sophisticated tertiary-care pediatric intensive care units in resource-rich regions due to advanced procedures such as transplantation, cardiac surgery, and other hospital-acquired causes, to primary care preventable causes, such as infectious diseases, snakebite, and so forth in rural parts of the developing world. The development and application of novel biomarkers, concepts such as the Renal Angina Index and advanced renal replacement therapy have revolutionized the era of treating AKI, but the cost and feasibility are the key determinants, especially in rural areas. In view of availability and expenses, peritoneal dialysis should be the first choice in less-developed areas, however, because of various barriers, it still needs more effort. Effective educational steps to both medical carers and families are needed urgently.

A meta-analysis of the incidence rate of postoperative acute kidney injury in patients with congenital heart disease

Background

Acute kidney injury (AKI) is a common complication of cardiac surgery. However, the incidence rate of AKI in patients with congenital heart disease (CHD) greatly varies between reports owing to the different definitions used for AKI. Therefore, this study was designed as a meta-analysis aimed at summarizing the incidence rate of AKI in patients with congenital heart disease (CHD) on the basis of different AKI criteria.

Methods

Studies published till April 24, 2020, on the incidence rate of AKI in patients with CHD, were retrieved from electronic databases and printed literature. To pool data from the included studies, the effect size, a combined statistics, was chosen and presented with the incidence rate and 95% confidence interval (CI). Heterogeneity was evaluated using I² statistics and Cochran Q test. The incidence rates obtained from the subgroup analysis according to study location, type of surgery, type of cohort, age, and AKI criteria) were also evaluated to determine the correlation of AKI with these factors. Publication bias was estimated using the Egger test.

Results

Thirty studies, comprising 9925 patients with AKI who had CHD, were included. Overall, the pooled incidence rate of AKI in the patients with CHD was 38.4% (95% CI, 32.0–44.7%). However, the incidence rate was not significantly affected by gender, study location, type of surgery, type of cohort, and AKI criteria. Moreover, age was significantly associated with the incidence of AKI, and the incidence rate was higher in the patients aged < 1 month than in those aged 1 month to 18 years, < 18 years, and ≥ 18 years (P < 0.05).

Conclusions

In this study, the estimated incidence rate of AKI in patients with CHD was 38.4% and may be influenced by age. These findings highlight the importance of further investigation of the specific causes of and effective preventive measures for AKI.

Prevalence and predictors of postoperative peritoneal dialysis in infants

BACKGROUND

Data regarding predictors of the eventual need for postoperative peritoneal dialysis in infants undergoing open heart surgery is still limited. We aimed to determine whether prolonged cardiopulmonary bypass time, surgical complexity classified according to Risk Adjustment for Congenital Heart Surgery category, younger age, and lower body weight increase the probability of requiring postoperative peritoneal dialysis.

METHODS

We retrospectively analyzed data of 181 infants who underwent open heart surgery at our institution from January 1 to December 31, 2018. Cardiopulmonary bypass time, Risk Adjustment for Congenital Heart Surgery category, age, body weight, and the need for postoperative peritoneal dialysis were recorded and analyzed.

RESULTS

Thirteen (7.2%) of the 181 patients required postoperative peritoneal dialysis. This group was found to have a longer cardiopulmonary bypass time, younger age, and lower body weight. Longer cardiopulmonary bypass time (p = 0.001), higher Risk Adjustment for Congenital Heart Surgery category (p = 0.018), younger age (p < 0.001), and lower body weight (p < 0.001) significantly increased the risk of postoperative peritoneal dialysis.

CONCLUSION

Longer cardiopulmonary bypass time, more complex surgery, younger age, and lower body weight increase the probability of requiring postoperative peritoneal dialysis in infants undergoing open heart surgery.

Incidence, risk factors, and outcomes of acute kidney injury in neonates after surgical procedures

BACKGROUND

Acute kidney injury (AKI) is common and associated with poor outcomes in critically ill neonates. The objective of this study was to study the incidence, risk factors, and clinical outcomes of AKI in neonates receiving non-cardiac surgery.

METHODS

We performed a single-center retrospective study between January 2017 and December 2018 of neonates who had received abdominal and thoracic surgical procedures. AKI was defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Patient information, clinical data, and outcomes were collected and analyzed. Logistic regression was used to analyze risk factors of AKI and association between AKI and mortality.

RESULTS

Fifty-four (33.8%) of 160 patients developed AKI after surgical procedures. Compared with neonates without AKI, neonates with AKI had higher mortality rate (18.5% VS 5.7%, p = 0.022), lower gestational age (30.5 weeks, interquartile range [IQR] 28-33.5, VS 34.5 weeks, IQR 33-37.5, p = 0.035), higher rates of very low birth weight (33.3% VS 17.0%, p = 0.019), longer duration of mechanical ventilation (0.5 days, IQR 0-1.5, VS 0 days, IQR 0-1, p = 0.043) and higher rates of sepsis (35.2% VS 19.8%, p = 0.034). Risk factors of AKI included gestational age under 32 weeks (OR 4.8, 95% CI 1.8-12.6; p = 0.001), sepsis (OR 4.3, 95% CI 1.7-11.3; p = 0.003), operation time longer than 120 min (OR 2.7, 95% CI 1.1-6.6; p = 0.024), and diagnosis of necrotizing enterocolitis (OR 3.5, 95% CI 1.3-9.1; p = 0.011). AKI after surgery was significantly associated with mortality (OR 4.3, 95% CI 1.1-16.9; p = 0.036).

CONCLUSIONS

AKI is common and associated with poor outcomes in surgical neonates. Early recognition and intervention of AKI in these patients are important.

Early prediction of acute kidney injury in neonates with cardiac surgery

Background

Acute kidney injury (AKI) occurs in 42%–64% of the neonatal patients experiencing cardiac surgery, contributing to postoperative morbidity and mortality. Current diagnostic criteria, which are mainly based on serum creatinine and hourly urine output, are not sufficiently sensitive and precise to diagnose neonatal AKI promptly. The purpose of this review is to screen the recent literature, to summarize the novel and cost-effective biomarkers and approaches for neonatal AKI after cardiac surgery (CS-AKI), and to provide a possible research direction for future work.

Data sources

We searched PubMed for articles published before November 2019 with pertinent terms. Sixty-seven articles were found and screened. After excluding 48 records, 19 articles were enrolled for final analysis.

Results

Nineteen articles were enrolled, and 18 possible urinary biomarkers were identified and evaluated for their ability to diagnose CS-AKI. Urinary neutrophil gelatinase-associated lipocalin (uNGAL), serum cystatin C (sCys), urinary human kidney injury molecule-1 (uKIM-1), urinary liver fatty acid-binding protein (uL-FABP) and interleukin-18 (uIL-18) were the most frequently described as the early predictors of neonatal CS-AKI.

Conclusions

Neonates are vulnerable to CS-AKI. UNGAL, sCys, uL-FABP, uKIM-1 and uIL-18 are potential biomarkers for early prediction of neonatal CS-AKI. Renal regional oxygen saturation by near-infrared spectroscopy is a non-invasive approach for early identification of neonatal AKI. Further work should focus on exploring a sensitive and specific combined diagnostic model that includes novel biomarkers and other complementary methods.

Racial and health insurance disparities in pediatric acute kidney injury in the USA

BACKGROUND

Acute kidney injury (AKI) significantly increases morbidity and mortality for hospitalized children, yet sociodemographic risk factors for pediatric AKI are poorly described. We examined sociodemographic differences in pediatric AKI amongst a national cohort of hospitalized children.

METHODS

Secondary analysis of the most recent (2012) Kids' Inpatient Database (KID) from the Agency for Healthcare Research and Quality. Study sample weights were used to obtain national estimates of AKI (defined by administrative data). KID is a nationally representative sample of pediatric discharges throughout the USA. Linear risk regression models were used to assess the relationship between our primary exposures (race/ethnicity, health insurance, household urbanization, gender, and age) and the diagnosis of AKI, adjusting for comorbidities.

RESULTS

A total of 1,699,841 hospitalizations met our study criteria. In 2012, AKI occurred in approximately 12.3/1000 pediatric hospitalizations, which translates to almost 30,000 children nationally. Asian/Pacific Islander, African-American, and Hispanic children were at slightly increased risk for AKI compared to Caucasian children (adjusted risk difference (RD) 4.5 per 1000 hospitalizations, 95% confidence interval (CI) 2.9-6.0; 2.5/1000 hospitalizations, 95% CI 1.7-3.3; and 1.7/1000 hospitalizations, 95% CI 0.9-2.5, respectively). Uninsured children were more likely to suffer AKI compared to children with any health insurance (e.g., no insurance versus Medicaid: adjusted RD 14.4/1000 hospitalizations, 95% CI 12.7-16.2). Based on these national estimates, one episode of AKI might be prevented if 70 (95% CI 62-79) hospitalized children without insurance were provided with Medicaid.

CONCLUSIONS

Pediatric AKI occurs more frequently in racial minority and uninsured children, factors linked to lower socioeconomic status.

Association of postoperative fluid overload with adverse outcomes after congenital heart surgery: a systematic review and dose-response meta-analysis

BACKGROUND

Pediatric cardiac surgery is commonly associated with acute kidney injury (AKI) and significant fluid retention, which complicate postoperative management and lead to increased rates of morbidity. This meta-analysis aimed to accumulate current literature evidence and evaluate the correlation of fluid overload degree with adverse outcome in patients undergoing congenital heart surgery.

METHODS

Medline, Scopus, CENTRAL, Clinicaltrials.gov, and Google Scholar were systematically searched from inception. All studies reporting the effects of fluid overload on postoperative clinical outcomes were selected. A dose-response meta-analytic method using restricted cubic splines was implemented in R-3.6.1.

RESULTS

Twelve studies were included, with a total of 3111 pediatric patients. Qualitative synthesis indicated that fluid overload was linked to significantly higher risk of mortality, AKI, prolonged hospital, and intensive care unit (ICU) stay, as well as with increased duration of mechanical ventilation, inotrope need, and infection rate. Meta-analysis demonstrated a linear correlation between fluid overload and the risk of mortality (χ² = 6.22, p value = 0.01) and AKI (χ² = 35.84, p value < 0.001), while a positive curvilinear relationship was estimated for the outcomes of hospital (χ² = 18.84, p value = 0.0001) and ICU stay (χ² = 63.69, p value = 0.0001).

CONCLUSIONS

The present meta-analysis supports that postoperative fluid overload is significantly linked to elevated risk of prolonged hospital stay, AKI development, and mortality in pediatric patients undergoing cardiac surgery. These findings warrant replication by future prospective studies, which should define the optimal cutoff values and assess the effectiveness of therapeutic strategies to limit fluid overload in the postoperative setting.

The Year in Review: Anesthesia for Congenital Heart Disease 2019

This review focuses on the literature published from January 2019 to February 2020 that is of interest to anesthesiologists taking care of children and adults with congenital heart disease. Five themes are addressed during this time period, and 59 peer-reviewed articles are discussed.

Variation in clinical usefulness of biomarkers of acute kidney injury in young children undergoing cardiac surgery

BACKGROUND

Acute kidney injury (AKI) is one of the most significant postoperative complications of pediatric cardiac surgery. Because serum creatinine has limitations as a diagnostic marker of AKI, new biomarkers including neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and interleukin-18 (IL-18) are being evaluated to overcome these limitations and detect AKI at an early stage after cardiac surgery.

PURPOSE

This study aimed to investigate the clinical usefulness of these biomarkers in young children.

METHODS

Thirty patients with congenital heart diseases who underwent cardiac surgery using cardiopulmonary bypass (CPB) were selected, and their urine and blood samples were collected at baseline and 6, 24, and 48 hours after surgery. Serum creatinine and blood urea nitrogen levels as well as NGAL, KIM-1, and IL-18 levels in urine samples were measured, and clinical parameters were evaluated.

RESULTS

Of the 30 patients, 12 developed AKI within 48 hours after cardiac surgery. In the AKI group, 8 of 12 (66.6%) met AKI criteria after 24 hours, and urine KIM-1/creatinine (Cr) level (with adjustment of urine creatinine) peaked at 24 hours with significant difference from baseline level. Additionally, urine KIM-1/Cr level in the AKI group was significantly higher than in the non-AKI group at 6 hours. However, urine NGAL/Cr and IL-18/Cr levels showed no specific trend with time for 48 hours after cardiac surgery.

CONCLUSION

It is suggested that urine KIM-1/Cr concentration could be considered a good biomarker for early AKI prediction after open cardiac surgery using CPB in young children with congenital heart diseases.