Acute kidney injury after cardiac surgery in infants and children: evaluation of the role of angiotensin-converting enzyme inhibitors

Growth Failure in Children with Congenital Heart Disease

Background/Objectives: Growth failure is a common complication in children with congenital heart disease (CHD), yet its underlying mechanisms and consequences remain incompletely understood. This review aims to provide a comprehensive overview of growth failure in children with CHD and outline a framework of factors contributing to this condition. Methods: To lay the foundation for this narrative review, several databases were searched using broad search terms related to CHD and growth failure. Results: Growth failure is most pronounced during the first year of life, but often improves after achieving hemodynamic stability through surgical or medical interventions. However, children with complex conditions, such as single-ventricle physiology or multiple heart defects, may experience persistent growth impairment due to chronic disease effects. Specific features of CHD-cyanosis, pulmonary hypertension, and low cardiac output-can further hinder growth by disrupting endocrine function and impairing musculoskeletal development. Long-term use of medications and exposure to repeated diagnostic procedures also contribute to growth failure. Beyond physical effects, growth failure profoundly influences neurodevelopment, psychosocial well-being, and survival outcomes. Based on our review, we have developed a knowledge map to better understand the complexities of growth failure in children with CHD. Conclusions: A thorough understanding of the multifaceted contributors to growth failure in CHD is essential for identifying high-risk children and devising strategies to support optimal growth. Integrating this knowledge into clinical practice can improve long-term outcomes for children with CHD.

Incidence and risk factors of drug-induced kidney injury in children: a systematic review and meta-analysis

PURPOSE

To comprehensively summarize the incidence and risk factors of drug-induced kidney injury (DIKI) in children.

METHODS

We systematically searched seven databases from inception to November 2022. Two independent reviewers selected studies, extracted data, and assessed the risk of bias. Meta-analyses were conducted to quantify the incidence and risk factors of DIKI in children.

RESULTS

A total of 69 studies comprising 195,894 pediatric patients were included. Overall, the incidence of DIKI in children was 18.2% (95%CI: 16.4%-20.1%). The incidence of DIKI in critically ill children (19.6%, 95%CI: 15.9%-23.3%) was higher than that in non-critically ill children (16.1%, 95%CI: 12.9%-19.4%). Moreover, the risk factors for DIKI in children were intensive care unit (ICU) admission (OR = 1.59, 95% CI: 1.42-1.78, P = 0.000), treatment days (OR = 1.04, 95% CI: 1.03-1.05, P = 0.000), surgical intervention (OR = 1.43, 95% CI: 1.00-2.02, P = 0.048), infection (OR = 2.30, 95% CI: 1.44-3.66, P = 0.000), patent ductus arteriosus (OR = 4.78, 95% CI: 1.82-12.57, P = 0.002), chronic kidney disease (OR = 2.78, 95% CI: 1.92-4.02, P = 0.000), combination with antibacterial agents (OR = 1.98, 95% CI: 1.54-2.55, P = 0.000), diuretics (OR = 1.97, 95% CI: 1.51-2.56, P = 0.000), combination with antiviral agents (OR = 1.50, 95% CI: 1.11-2.04, P = 0.008), combination with non-steroidal anti-inflammatory drugs (OR = 1.79, 95% CI: 1.40-2.28, P = 0.000), and combination with immunosuppressive agents (OR = 2.84, 95% CI: 1.47-5.47, P = 0.002).

CONCLUSION

The incidence of DIKI in children is high, especially in critically ill children. Identifying high-risk groups and determining safer treatments is critical to reducing the incidence of DIKI in children. In clinical practice, clinicians should adjust medication regimens for high-risk pediatric groups, such as ICU admission, some underlying diseases, combination with nephrotoxic drugs, etc., and regularly evaluate kidney function throughout treatment.

Kidney disease and congenital heart disease: Partnership for life

The literature on the relationship between kidney and cardiovascular diseases is continuously expanding. Scientists have elucidated many of the neurohormonal and hemodynamic pathways involved in cardiorenal disease. However, little is known about kidney disease in patients with congenital heart disease. Given advances in the medical and surgical care of this highly complex patient population, survival rates have dramatically improved leading to a higher percentage of adults living with congenital heart disease. Accordingly, a noticeable increase in the prevalence of kidney disease is appreciated in these patients. Some of the main risk factors for developing chronic kidney disease in the adult congenital heart disease population include chronic hypoxia, neurohormonal derangements, intraglomerular hemodynamic changes, prior cardiac surgeries from minimally invasive to open heart surgeries with ischemia, and nephrotoxins. Unfortunately, data regarding the prevalence, pathophysiology, and prognosis of chronic kidney disease in the adult congenital heart disease population remain scarce. This has led to a lack of clear recommendations for evaluating and managing kidney disease in these patients. In this review, we discuss contemporary data on kidney disease in adults with congenital heart disease in addition to some of the gaps in knowledge we face. The article highlights the delicate interaction between disease of the heart and kidneys in these patients, and offers the practitioner tools to more effectively manage this vulnerable population.

Impact of acute kidney injury in patients prescribed angiotensin-converting enzyme inhibitors over the first two years of life

BACKGROUND

The association of long-term acute kidney injury (AKI) risk with angiotensin-converting enzyme (ACE) inhibitor use in neonates/infants is poorly understood. We examined this association to identify potential AKI risk factors.

METHODS

We retrospectively evaluated 119 children aged < 2 years (72 boys; median age, 5.0 months) who received ACE inhibitors for congenital heart disease for ≥ 6 months between January 2009 and June 2019. We monitored the occurrence of AKI, defined according to the Kidney Disease Improving Global Outcomes guidelines. Demographic and clinical data were extracted from medical records. Risk factors associated with AKI onset were identified by a Cox proportional hazards regression analysis of variables previously identified as risk factors of AKI and those significant in a univariate analysis.

RESULTS

Thirty-three of 119 patients (28%) developed AKI at a median follow-up of 1.3 years (interquartile range, 0.8-3.2 years). AKI incidence was 1257 events per 10,000 patient-years. Concomitant tolvaptan use (hazard ratio [HR], 3.81; 95% confidence interval [CI], 1.82-7.97; P < 0.01) and Down syndrome (HR, 3.22; 95% CI, 1.43-7.29; P < 0.01) were identified as independent risk factors of AKI onset.

CONCLUSIONS

AKI was strongly associated with concomitant tolvaptan use and Down syndrome in our study population. Physicians should consider these factors when prescribing ACE inhibitors for neonates/infants. Low-dose ACE inhibitors slow CKD progression because of their antifibrotic properties. ACE inhibitors may be beneficial for patients with Down syndrome who have underlying CKD in a non-acute setting. Therefore, they should be administered to such patients with caution.

Angiotensin-Converting Enzyme Inhibitor Initiation and Dose Uptitration in Children With Cardiovascular Disease: A Retrospective Review of Standard Clinical Practice and a Prospective Randomized Clinical Trial

Background

Angiotensin‐converting enzyme inhibitors (ACEIs) are a mainstay of medical management in pediatric cardiology. However, there are no data defining how best to initiate and uptitrate the dose of these medications in children.

Methods and Results

Retrospective chart review revealed only 24% of our pediatric cardiology inpatients were discharged on predefined optimal doses of ACEIs and few underwent further dose uptitration in the 8 weeks after hospital discharge. Therefore, 2 alternative protocols for initiation of captopril were compared in a prospective randomized clinical trial. A “rapid uptitration” protocol reached an optimal dose on day 3, whereas the alternative, “prolonged uptitration” protocol, reached an optimal dose on day 9. Forty‐6 patients (54% male) were recruited to the trial, with a median age of 0.7 year (IQR 0.5–2.3 years). Captopril was initiated while in intensive care in 39% of patients and on the cardiology ward in 61%. There were no differences between the protocols in episodes of hypotension, symptomatic hypotension, or indices of renal function. Patients following the rapid protocol reached higher doses of captopril (0.93±0.24 versus 0.57±0.38 mg/kg per dose, P<0.0001) and were more likely to have achieved the predefined target (88% versus 43%, P=0.002) and optimal ACEI doses (80% versus 29%, P=0.001) before discharge.

Conclusions

A protocol of rapid ACEI dose uptitration for infants and children with cardiovascular disease can be introduced safely, even in patients receiving intensive care therapy. Compared with standard clinical practice or with a more prolonged protocol, rapid ACEI dose uptitration achieves a higher dosage in this population with no evident disadvantages.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00742040.

A Decline in Intraoperative Renal Near-Infrared Spectroscopy Is Associated With Adverse Outcomes in Children Following Cardiac Surgery

OBJECTIVES

Renal near-infrared spectroscopy is known to be predictive of acute kidney injury in children following cardiac surgery using a series of complex equations and area under the curve. This study was performed to determine if a greater than or equal to 20% reduction in renal near-infrared spectroscopy for 20 consecutive minutes intraoperatively or within the first 24 postoperative hours is associated with 1) acute kidney injury, 2) increased acute kidney injury biomarkers, or 3) other adverse clinical outcomes in children following cardiac surgery.

DESIGN

Prospective single center observational study.

SETTING

Pediatric cardiac ICU.

PATIENTS

Children less than or equal to age 4 years who underwent cardiac surgery with the use of cardiopulmonary bypass during the study period (June 2011-July 2012).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A reduction in near-infrared spectroscopy was not associated with acute kidney injury. Nine of 12 patients (75%) with a reduction in renal near-infrared spectroscopy did not develop acute kidney injury. The remaining three patients had mild acute kidney injury (pediatric Risk, Injury, Failure, Loss, End stage-Risk). A reduction in renal near-infrared spectroscopy was associated with the following adverse clinical outcomes: 1) a longer duration of mechanical ventilation (p = 0.05), 2) longer intensive care length of stay (p = 0.05), and 3) longer hospital length of stay (p < 0.01). A decline in renal near-infrared spectroscopy in combination with an increase in serum interleukin-6 and serum interleukin-8 was associated with a longer intensive care length of stay, and the addition of urine interleukin-18 to this was associated with a longer hospital length of stay.

CONCLUSIONS

In this cohort, the rate of acute kidney injury was much lower than anticipated thereby limiting the evaluation of a reduction in renal near-infrared spectroscopy as a predictor of acute kidney injury. A greater than or equal to 20% reduction in renal near-infrared spectroscopy was significantly associated with adverse outcomes in children following cardiac surgery. The addition of specific biomarkers to the model was predictive of worse outcomes in these patients. Thus, real-time evaluation of renal near-infrared spectroscopy using the specific levels of change of a 20% reduction for 20 minutes may be useful in predicting prolonged mechanical ventilation and other adverse outcomes in children undergoing cardiac surgery.

Drugs as risk factors of acute kidney injury in critically ill children

BACKGROUND

Acute kidney injury (AKI) is a serious condition in critically ill children. Nephrotoxic medication exposure is a common contributing factor to AKI, but little literature is available in pediatrics. The aim of the present study was to assess potential associations between drugs and the risk of developing AKI.

METHODS

We performed a retrospective case-control study in a pediatric intensive care unit (PICU). Cases were patients who developed AKI during PICU stay. Patients without AKI served as controls and were matched to cases by age and gender in a one-to-one ratio.

RESULTS

One hundred case-control pairs were included. Cases were not statistically different from controls with regard to median weight and main diagnoses, but differed with regard to the need for mechanical ventilation, severity of illness, and median length of PICU stay. Multivariate models revealed a statistically significant higher risk of developing AKI for patients treated with metamizole, morphine, paracetamol, and tropisetron. A similar risk could be shown for medication groups, namely glucocorticoids, betalactam antibiotics, opioids, and non-steroidal anti-inflammatory drugs.

CONCLUSIONS

The results suggest that drugs are associated with acute renal dysfunction in critically ill children, but the multifactorial causes of AKI should be kept in mind.

Chronic kidney disease in congenital heart disease patients: a narrative review of evidence

Purpose of review

Patients with congenital heart disease have a number of risk factors for the development of chronic kidney disease (CKD). It is well known that CKD has a large negative impact on health outcomes. It is important therefore to consider that patients with congenital heart disease represent a population in whom long-term primary and secondary prevention strategies to reduce CKD occurrence and progression could be instituted and significantly change outcomes. There are currently no clear guidelines for clinicians in terms of renal assessment in the long-term follow up of patients with congenital heart disease. Consolidation of knowledge is critical for generating such guidelines, and hence is the purpose of this view. This review will summarize current knowledge related to CKD in patients with congenital heart disease, to highlight important work that has been done to date and set the stage for further investigation, development of prevention strategies, and re-evaluation of appropriate renal follow-up in patients with congenital heart disease.

Sources of information

The literature search was conducted using PubMed and Google Scholar.

Findings

Current epidemiological evidence suggests that CKD occurs in patients with congenital heart disease at a higher frequency than the general population and is detectable early in follow-up (i.e. during childhood). Best evidence suggests that approximately 30 to 50 % of adult patients with congenital heart disease have significantly impaired renal function. The risk of CKD is higher with cyanotic congenital heart disease but it is also present with non-cyanotic congenital heart disease. Although significant knowledge gaps exist, the sum of the data suggests that patients with congenital heart disease should be followed from an early age for the development of CKD.

Implications

There is an opportunity to mitigate CKD progression and negative renal outcomes by instituting interventions such as stringent blood pressure control and reduction of proteinuria. There is a need to invest time, thought and money to fill existing knowledge gaps to improve health outcomes in this population. This review should serve as an impetus for generation of follow-up guidelines of kidney health evaluation in patients with congenital heart disease.

Urinary Albumin Levels Predict Development of Acute Kidney Injury After Pediatric Cardiac Surgery: A Prospective Observational Study

OBJECTIVE

Mortality and morbidity of acute kidney injury (AKI) after cardiac surgery still remain high. The authors undertook the present study to evaluate the utility of early postoperative urinary albumin (uAlb) as a diagnostic marker for predicting occurrence of AKI and its severity in pediatric patients undergoing cardiac surgery.

DESIGN

A prospective observational study.

SETTING

A single-institution university hospital.

PARTICIPANTS

All patients<18 years of age who underwent repair of congenital heart disease with cardiopulmonary bypass between July 2010 and July 2012 were included in the study. Neonates age<1 month were excluded from the study population.

INTERVENTIONS

The association between uAlb and occurrence of AKI within 3 days after admission to the intensive care unit was investigated. Criteria from pediatric-modified Risk Injury Failure Loss and End-stage kidney disease (pRIFLE) were used to determine the occurrence of AKI. The value of uAlb was measured at intensive care unit admission immediately after cardiac surgery in all participants from whom a 5-mL urine sample was obtained.

MEASUREMENTS AND MAIN RESULTS

Of 376 patients, AKI assessed by pRIFLE was identified in 243 (64.6%): 172 for risk (R; 45.7%), 44 for injury (I; 11.7%), and 27 for failure (F; 7.2%). One hundred thirty-three patients (35.4%) were classified as being without AKI (normal [N]) by pRIFLE. The concentration of uAlb was significantly higher in AKI patients than in non-AKI patients (median [interquartile range]): uAlb (µg/mL): 13.5 (6.4-39.6) v 6.0 (3.4-16), p<0.001; uAlb/Cr (mg/gCr): 325 (138-760) v 121 (53-269), p< 0.001.

CONCLUSIONS

The utility of uAlb for prompt diagnosis of AKI was shown. Obtaining uAlb measurements early after pediatric cardiac surgery may be useful for predicting the occurrence and severity of AKI.

Hypotension as the etiology for angiotensin-converting enzyme (ACE) inhibitor-associated acute kidney injury in pediatric patients

This retrospective study aimed to compare systolic and diastolic blood pressures between patients with acute kidney injury (AKI) after initiation of angiotensin-converting enzyme (ACE) inhibitor therapy and those of patients who do not experience AKI after ACE inhibitor therapy. Of 332 patients who received an ACE inhibitor as inpatients at our institution from 1 January 2010 to 1 July 2012, 20 patients had a doubling of serum creatinine (SCr) within 72 h after initiation or dose uptitration of an ACE inhibitor (AKI group). These cases were matched one to four by age and gender to patients who received an ACE inhibitor but did not have a doubling of SCr (control group). The patients in the AKI group had a significantly greater decrease in systolic and diastolic blood pressures before their AKI than the control group. Pediatric patients who experience ACE inhibitor-associated AKI have a significantly greater decrease in blood pressure than patients who do not experience ACE inhibitor-associated AKI. The authors suggest that the risk and benefits of ACE inhibitor use be stringently evaluated before initiation of therapy.

Angiotensin-converting enzyme inhibitor nephrotoxicity in neonates with cardiac disease

Angiotensin-converting enzyme inhibitors (ACEi) are commonly used for pediatric cardiology patients. However, studies examining their safety for neonates with cardiac disease are scarce. The current study aimed to test the hypothesis that ACEi-mediated nephrotoxicity occurs in neonates and may be underappreciated in this population. A retrospective review of 243 neonates with cardiac disease between 2007 and 2010 was performed. Demographic data, weight, length, captopril and enalapril dosing, serum [K⁺], serum creatinine, and concomitant medications during ACEi therapy were recorded and analyzed. Body surface area (BSA), creatinine clearance (CrCl), and change in [K⁺] were calculated. The age range of neonates at ACEi initiation was 15.9-18.1 days. The inclusion criteria was met by 206 neonates: 168 term (82%) and 38 preterm (18%) newborns. Of these neonates, 42% were female, and all the patients had a BSA smaller than 0.33 m² (a group known to have relative renal insufficiency). The mean dose of enalapril was 0.08 ± 0.007 mg/kg for the preterm neonates and 0.08 ± 0.003 mg/kg for the term neonates. The mean dose of captopril was 0.07 ± 0.009 mg/kg for the preterm neonates and 0.13 ± 0.019 mg/kg for the term neonates. A significant decrease in CrCl occurred for both the preterm (p < 0.01) and term (p < 0.001) neonates while they were receiving ACEi. However, the two groups did not differ significantly (p = 0.183). Nearly 42% of all the patients showed renal risk, with approximately 30% demonstrating renal failure by modified pRIFLE (pediatric risk, injury, failure, loss, and end-stage renal disease) criteria. Despite the lack of significantly different CrCl, the premature neonates were more likely to experience ACEi-related renal failure by pRIFLE (55%) than their term counterparts (23%; p < 0.001). Despite its common use for term neonates with cardiac disease, ACEi should be used cautiously and only when indications are clear. These results also raise the question whether ACEi should be used at all for preterm neonates.

Preoperative prediction of acute kidney injury--from clinical scores to biomarkers

Early acute kidney injury (AKI) diagnosis in critically ill children has been an important recent research focus because of the known association of AKI with poor outcomes and the requirement of early intervention to mitigate negative effects of AKI. In children having surgery, the preoperative period offers a unique opportunity to predict postoperative acute kidney injury (AKI), well before AKI occurs. Pediatric AKI epidemiologic studies have begun to identify which preoperative factors may predict development of postoperative cardiac surgery. Using these clinical risk factors, it may be possible to derive preoperative clinical risk scores and improve upon our ability to risk-stratify children into AKI treatment trials, pre-emptively provide conservative renal injury prevention strategies, and ultimately improve patient outcomes. Developing risk scores requires rigorous methodology and validation before widespread use. There is little information currently on the use of preoperative biological or physiological biomarkers to predict postoperative AKI, representing an important area of future research. This review will provide an overview of methodology of preoperative risk score development, discuss pediatric-specific issues around deriving such risk scores, including the combination of preoperative clinical and biologic biomarkers for AKI prediction, and suggest future research avenues.