Acute kidney injury in congenital cardiac surgery: Pediatric risk-injury-failure-loss-end-stage renal disease and Acute Kidney Injury Network

Acute Kidney Injury Requiring Dialysis After Pediatric Heart Transplant

BACKGROUND

Acute kidney injury (AKI) is a common complication of pediatric heart transplant, with a subset of patients developing severe AKI requiring dialysis (AKI-D). We aimed to identify the epidemiology, risk factors, and outcomes of postoperative AKI-D in pediatric heart transplant recipients.

METHODS

We retrospectively identified all pediatric first-time, single-organ heart transplants at our institution from 2014 to 2022. Postoperative AKI was defined as AKI within 2 weeks of transplant. Unadjusted and adjusted logistic regression were used to identify characteristics associated with AKI-D, and unadjusted time-to-event analyses were used to determine the association between AKI-D and survival free of kidney failure.

RESULTS

Among 177 patients included, 116 (66%) developed postoperative AKI of any stage, including 13 (7%) who developed AKI-D with median time from transplant to dialysis initiation of 6 days (IQR 3-13). In adjusted models, increased cardiopulmonary bypass time (OR 1.19, 95% CI 1.04-1.37, per 15 min increase in bypass time) and higher weight at transplant were associated with higher odds of AKI-D, whereas patient demographics and pretransplant kidney function were not associated with AKI-D. AKI-D was associated with greater mortality during initial hospitalization (46% vs. 1%, p < 0.001) and a lower rate of survival free of kidney failure.

CONCLUSIONS

The incidence of AKI-D after pediatric heart transplant was 7%, with extended cardiopulmonary bypass time associated with postoperative AKI-D even in adjusted models. Further research is needed to improve the prediction and management of AKI-D in this population.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Post Cardiac Surgery

INTRODUCTION

The long-term renal outcomes of survivors of pediatric acute kidney injury (AKI) are varied within the current literature, and we aim to establish long-term renal outcomes for pediatric patients after cardiac surgery. We studied long-term renal outcomes and markers of kidney injury in pediatric patients after congenital cardiac surgery.

METHODS

In a prospective case-control observational study (the Renal Outcomes in Children with acute Kidney injury post cardiac Surgery [ROCKS] trial) we reviewed all children who underwent cardiac surgery on cardiopulmonary bypass (December 2010-2017).

RESULTS

During the study period, 2035 patients underwent cardiac surgery, of whom 9.8% developed AKI postoperatively. Forty-four patients who had postoperative AKI had a long-term follow-up, met our inclusion criteria, and were compared with 49 control subjects. We conducted a univariate analysis of reported parameters. At a median follow-up of 41 months, the cases had significantly higher urine levels of neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), and kidney injury molecule-1 (KIM-1). The biomarkers remained higher after adjusting for the urine creatinine, and the ratio of urine KIM-1/urine creatinine was significantly higher among cases. None of the patients had proteinuria or hypertension on follow-up. The presence of AKI, AKI stage, and younger age were not associated with the occurrence of low glomerular filtration rate (GFR) at follow-up.

CONCLUSIONS

Urinary biomarker abnormalities persist years after a congenital cardiac surgery in children, who may have a low GFR on follow-up. The presence of AKI, AKI stage, and younger age at surgery are not associated with the occurrence of low GFR at follow-up. Children with a higher surgical complexity score have lower GFR on follow-up.

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.

Long-term survival of children following acute peritoneal dialysis in a resource-limited setting

BACKGROUND

There is a paucity of data on long term-outcomes of children who undergo acute peritoneal dialysis (PD) in resource-limited settings. We reviewed the outcomes of children who underwent PD after 18 months of follow-up.

METHODS

We conducted a prospective cohort study in children with acute kidney injury (AKI) who underwent PD. Diagnosis of AKI was based on the 2012 Kidney Disease: Improving Global Outcomes definition. We assessed outcomes of in-hospital mortality, 18-month post-dialysis survival, factors associated with survival, and progression to chronic kidney disease (CKD).

RESULTS

Twenty-nine children with a median age of 6 (3 to 11) years underwent acute PD. In-hospital mortality was 3/29 (10.3%) and rose to 27.6% during follow-up. Seven (24.1%) children were lost to follow-up. Of the 14 remaining children, six (42.9%) experienced full recovery of renal function, while eight (57.1%) progressed to CKD. Among those who experienced full recovery, median (interquartile range) estimated glomerular filtration rate (eGFR) rose from 12.67 (7.05, 22.85) mL/min/1.73 m2 to 95.56 (64.50, 198.00) mL/min/1.73 m2, P = 0.031. No significant changes in median eGFR from baseline were observed among those who progressed to CKD (P = 0.383) or in non-survivors (P = 0.838). According to Kaplan-Meier curve analyses, 18-month survival during follow-up was 66.0% (95% CI, 45.0% to 86.5%). Age < 5 was associated with greater likelihood of survival (OR, 3.217; 95% CI, 1.240 to 8.342).

CONCLUSION

Progression of post-PD AKI to CKD occurred in more than half of survivors. Age < 5 was associated with greater likelihood of survival.

Acute Kidney Injury and Risk of CKD and Hypertension after Pediatric Cardiac Surgery

BACKGROUND AND OBJECTIVES

The association of AKI after pediatric cardiac surgery with long-term CKD and hypertension development is unclear. The study objectives were to determine whether AKI after pediatric cardiac surgery is associated with incident CKD and hypertension.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a prospective cohort study of children of 1 month to 18 years old who were undergoing cardiac surgery at two tertiary care centers (Canada, United States). Participants were recruited before cardiac surgery and were followed during hospitalization and at 3, 12, 24, 36, and 48 months after discharge. Exposures were postoperative AKI, based on the Kidney Disease Improving Global Outcomes (KDIGO) definition, and age <2 years old at surgery. Outcomes and measures were CKD (low eGFR or albuminuria for age) and hypertension (per the 2017 American Academy of Pediatrics guidelines) at follow-up, with the composite outcome of CKD or hypertension.

RESULTS

Among 124 participants, 57 (46%) developed AKI. AKI versus non-AKI participants had a median (interquartile range) age of 8 (4.8-40.8) versus 46 (6.0-158.4) months, respectively, and higher preoperative eGFR. From the 3- to 48-month follow-up, the cohort prevalence of CKD was high (17%-20%); hypertension prevalence was also high (22%-30%). AKI was not significantly associated with the development of CKD throughout follow-up. AKI was associated with hypertension development at 12 months after discharge (adjusted relative risk, 2.16; 95% confidence interval, 1.18 to 3.95), but not at subsequent visits. Children aged <2 years old at surgery had a significantly higher prevalence of hypertension during follow-up than older children (40% versus 21% at 3-month follow-up; 32% versus 13% at 48-month follow-up).

CONCLUSIONS

CKD and hypertension burden in the 4 years after pediatric cardiac surgery is high. Young age at surgery, but not AKI, is associated with their development.

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.

Acute Kidney Injury in Hospitalized Pediatric Patients: A Review of Research

INTRODUCTION

Pediatric patients who develop acute kidney injury (AKI) while hospitalized have longer hospital stays, increased morbidity and mortality, and are at an increased risk for developing chronic kidney disease. Early recognition of AKI is becoming a major clinical focus. There is little research focusing on nursing interventions that may affect a pediatric patient's risk for developing AKI. The purpose of this review is to summarize reported predictors of AKI to improve its early recognition and treatment among hospitalized pediatric patients.

METHODS

A review of research was conducted to further identify risk factors of AKI among noncritically ill hospitalized pediatric patients.

RESULTS

The current literature demonstrated inconsistent findings in early recognition of AKI among hospitalized pediatric patients.

DISCUSSION

Interventions for early recognition and treatment of AKI should consider other variables, such as previous history of AKI and fluid status as risk factors, warranting additional research.

Risk Factors for Recurrent Acute Kidney Injury in Children Who Undergo Multiple Cardiac Surgeries: A Retrospective Analysis

OBJECTIVES

Determine the risk factors for repeated episodes of acute kidney injury in children who undergo multiple cardiac surgical procedures.

DESIGN

Single-center retrospective chart review.

SETTING

Cardiac ICU at a quaternary pediatric care center.

PATIENTS

Birth to 18 years who underwent at least two cardiac surgical procedures with cardiopulmonary bypass.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One-hundred eighty patients underwent two cardiac surgical procedures and 89 underwent three. Acute kidney injury was defined by the Kidney Disease: Improving Global Outcomes serum creatinine criteria. Acute kidney injury frequency was 26% (n = 46) after surgery 1, 20% (n = 36) after surgery 2, and 24% (n = 21) after surgery 3, with most acute kidney injury occurring on postoperative days 1 and 2. The proportion of patients with severe acute kidney injury increased from surgery 1 to surgery 3. Patients with acute kidney injury had a significantly longer duration of ventilation and length of stay after each surgery. The odds of acute kidney injury after surgery 3 was 2.40 times greater if acute kidney injury was present after surgery 1 or 2 (95% CI, 1.26-4.56; p = 0.008) after adjusting for confounders. The time between surgeries was not significantly associated with acute kidney injury (p = 0.85).

CONCLUSIONS

In a heterogeneous population of pediatric patients with congenital heart disease undergoing multiple cardiopulmonary bypass surgeries, odds of acute kidney injury after a third surgery was increased by the presence of acute kidney injury after prior procedures. Time between surgery did not play a role in increasing odds of acute kidney injury. Further studies in a larger multicenter investigation are necessary to confirm these findings.

Acute kidney injury after pediatric cardiac surgery

Acute kidney injury (AKI) is a common complication of pediatric cardiac surgery and is associated with increased morbidity and mortality. Literature of AKI after pediatric cardiac surgery is comprehensively reviewed in terms of incidence, risk factors, biomarkers, treatment and prognosis. The novel RIFLE (pediatric RIFLE for pediatrics), Acute Kidney Injury Network (AKIN) and Kidney Disease Improving Global Outcomes (KDIGO) criteria have brought about unified diagnostic standards and comparable results for AKI after cardiac surgery. Numerous risk factors, either renal or extrarenal, can be responsible for the development of AKI after cardiac surgery, with low cardiac output syndrome being the most pronounced predictor. Early fluid overload is also crucial for the occurrence of AKI and prognosis in pediatric patients. Three sensitive biomarkers, neutrophil gelatinase-associated lipocalin, cystatin C (CysC) and liver fatty acid-binding protein, are regarded as the earliest (increase at 2-4 h), and another two, kidney injury molecule-1 and interleukin-18 represent the intermediate respondents (increase at 6-12 h after surgery). To ameliorate the cardiopulmonary bypass techniques, improve renal perfusion and eradicate the causative risk factors are imperative for the prevention of AKI in pediatric patients. The early and intermediate biomarkers are helpful for an early judgment of occurrence of postoperative AKI. Improved survival has been achieved by prevention, renal support and modifications of hemofiltration techniques. Further development is anticipated in small children.

Wider intraoperative glycemic fluctuation increases risk of acute kidney injury after pediatric cardiac surgery

OBJECTIVE

The association between poor intraoperative glycemic control and postoperative acute kidney injury (AKI) in adult cardiac surgery has been observed, but data in the pediatrics remain unknown. We performed a hypothesis that intraoperative hyperglycemia and/or wider glycemic fluctuation were associated with the incidence of postoperative AKI in pediatric cardiac surgery.

METHODS

A retrospective study was performed in pediatrics who underwent cardiac surgery from 2013 to 2016. Perioperative glycemic data up to 48 hours after surgery were collected and analyzed. Patients with AKI were matched 1:1 with patients without AKI by a propensity score. Variables of demographic data, preoperative renal function and glycemic level, perioperative cardiac condition were matched.

RESULTS

The incidence of AKI was 11.5% (118/1026), with 53.4% (63/118), 30.5% (36/118), and 16.1% (19/118) categorized as AKIN stages I, II, and III, respectively. Children who experienced AKI were younger and cyanotic, underwent more complex surgeries, had higher peak intraoperative glucose levels, wider intraoperative glycemic fluctuation, greater inotropic scores and more transfusions, and poor outcomes (all p < .05). After matching, the AKI group had significantly wider intraoperative glycemic fluctuation (p < .05). Logistic regression showed intraoperative glycemic fluctuation was one of the risk factors for AKI (p = .033) and degree of AKI severity stage increased when the glycemic fluctuation increased (p < .01).

CONCLUSIONS

Wider intraoperative glycemic fluctuation, but not hyperglycemia, was associated with an increased incidence of postoperative AKI after pediatric cardiac surgery.

Factors that influenced undergoing renal replacement therapy and survival in children with acute kidney injury

AIM

Acute kidney injury (AKI) is an important clinical condition that is associated with increased mortality and morbidity. This study was performed to identify the factors that influence AKI stage, undergoing renal replacement therapy (RRT) and mortality.

METHODS

This study was retrospectively conducted on 219 children with AKI who had been referred to the paediatric nephrology division of Dr Sami Ulus Teaching Hospital during their inpatient treatment from 2008 to 2012. AKI was defined using pRIFLE criteria.

RESULTS

From the 219 enrolled patients, 131 were identified as having AKI at the time of hospital admission. Infant age group was the largest group. RRT was performed in 68 patients. Median RRT initiation time was 1.5 day (0-2) and the mortality increased significantly when RRT initiation time was >1 day. The likelihood of undergoing RRT was higher for patients who were younger, who were managed in PICU and who had intrinsic type of AKI. pRIFLE stage and AKI place did not influence the likelihood of undergoing RRT. Overall mortality was 26.9%. In log-rank tests, factors influencing survival were younger age, being treated in PICU, developing AKI during inpatient treatment, having a comorbid condition and undergoing RRT. pRIFLE stage did not influence survival. In the logistic regression model, factors associated with mortality included younger age, undergoing RRT and having AKI during inpatient treatment. Having underlying disease and being managed in PICU did not influence the likelihood of death.

CONCLUSION

Acute kidney injury is an important condition in all hospitalized patients. More studies and interventions are needed on this topic to identify, treat and prevent AKI.