Novel Urinary Biomarkers for Acute Kidney Injury and Prediction of Clinical Outcomes After Pediatric Cardiac Surgery

Prediction of cardiac surgery associated acute kidney injury using response to loop diuretic and urine neutrophil gelatinase associated lipocalin

BACKGROUND

Cardiac surgery associated acute kidney injury (CS-AKI) is common. Urine response to loop diuretic and urine neutrophil gelatinase associated lipocalin (uNGAL) are separately associated with CS-AKI. We aimed to determine whether urine response to loop diuretic and uNGAL together were associated with postoperative day 2-4 CS-AKI.

METHODS

Two-center prospective observational study (ages 0-18 years). uNGAL (8-12 h after admission) (ng/mL) and urine response to loop diuretic (6 h for bolus furosemide and 12 h for infusion bumetanide) (mL/kg/hr) were measured. All diuretic doses were converted to furosemide equivalents. The primary outcome was day 2-4 CS-AKI. Patients were sub-phenotyped using a priori cutoffs (uNGAL +  ≥ 100 ng/mL and UOP +  < 1.5 mL/kg/hr) and optimal cutoffs (uNGAL +  ≥ 127 ng/mL and UOP +  ≤ 0.79 mL/kg/hr): 1) uNGAL-/UOP-, 2) uNGAL-/UOP + , 3) uNGAL + /UOP-, and 4) uNGAL + /UOP + . Multivariable regression was used to assess the association of uNGAL, UOP and each sub-phenotype with outcomes.

RESULTS

476 patients were included. CS-AKI occurred in 52 (10.9%). uNGAL was associated with 2.59-fold greater odds (95%CI: 1.52-4.41) of CS-AKI. UOP was not associated with CS-AKI. Compared with uNGAL + alone, uNGAL + /UOP + improved prediction of CS-AKI using a priori and optimal cutoffs respectively (AUC 0.70 vs. 0.75). Both uNGAL + /UOP + (IQR OR:4.63, 95%CI: 1.74-12.32) and uNGAL + /UOP- (IQR OR:5.94, 95%CI: 2.09-16.84) were associated with CS-AKI when compared with uNGAL-/UOP-.

CONCLUSIONS

uNGAL is associated with CS-AKI. The sub-phenotype association was largely driven by uNGAL. Future studies standardizing diuretic dose and timing may be needed to refine the combined performance for clinical decision making.

Perioperative Neonatal Acute Kidney Injury Is Common: Risk Factors for Poor Outcomes

OBJECTIVE

Perioperative acute kidney injury (AKI) is associated with poor patient outcomes. The epidemiology of perioperative AKI is characterized in children and to a lesser extent in neonates with cardiac disease. We hypothesized that the prevalence of noncardiac perioperative AKI in neonates is higher than in older children. We also hypothesized that certain neonatal characteristics and comorbidities increase the risk of perioperative AKI and hospital mortality. We aimed to characterize the epidemiology and risk factors of perioperative AKI in neonates undergoing noncardiac surgeries and outline the associated mortality risk factors.

STUDY DESIGN

We performed a retrospective study of neonates ≤28 days old who underwent inpatient noncardiac surgery in 46 U.S. children's hospitals participating in the Pediatric Hospital Information System between 2016 and 2021. AKI was evaluated throughout the surgical admission encounter. AKI was defined using the International Classification of Diseases (ICD) versions 9 and 10 codes. Comorbid risk factors are chronic and longstanding diagnoses and were selected using ICD-9 and ICD-10 diagnostic and procedure codes.

RESULTS

Perioperative AKI occurred in 10% of neonates undergoing noncardiac surgeries. Comorbidities associated with high risk of perioperative AKI included metabolic, hematologic/immunologic, cardiovascular, and renal disorders. The relative risk of mortality in perioperative AKI was highest in infants with low birthweight (relative risk = 1.49, 1.14-1.94) and those with hematologic (1.46, 1.12-1.90), renal (1.24, 1.01-1.52), and respiratory comorbidities (1.35, 1.09-1.67).

CONCLUSION

Perioperative AKI is common in neonates undergoing noncardiac surgeries. Infants with high-risk comorbidity profiles for the development of perioperative AKI and mortality may benefit from close surveillance of their kidney function in the perioperative period. Although retrospective, the findings of our study could inform clinicians to tailor neonatal perioperative kidney care to improve short- and long-term outcomes.

KEY POINTS

· AKI is common in neonates undergoing noncardiac surgeries.. · Extremely preterm and very low birth weight neonates have the highest rates of perioperative AKI.. · Renal, hematologic, and respiratory comorbidities increase mortality risk in neonates with perioperative AKI..

Urinary L-FABP as an Early Biomarker for Pediatric Acute Kidney Injury Following Cardiac Surgery with Cardiopulmonary Bypass: A Systematic Review and Meta-Analysis

Acute kidney injury (AKI) following surgery with cardiopulmonary bypass (CPB-AKI) is common in pediatrics. Urinary liver-type fatty acid binding protein (uL-FABP) increases in some kidney diseases and may indicate CPB-AKI earlier than current methods. The aim of this systematic review with meta-analysis was to evaluate the potential role of uL-FABP in the early diagnosis and prediction of CPB-AKI. Databases Pubmed/MEDLINE, Scopus, and Web of Science were searched on 12 November 2023, using the MeSH terms "Children", "CPB", "L-FABP", and "Acute Kidney Injury". Included papers were revised. AUC values from similar studies were pooled by meta-analysis, performed using random- and fixed-effect models, with p < 0.05. Of 508 studies assessed, nine were included, comprising 1658 children, of whom 561 (33.8%) developed CPB-AKI. Significantly higher uL-FABP levels in AKI versus non-AKI patients first manifested at baseline to 6 h post-CPB. At 6 h, uL-FABP correlated with CPB duration (r = 0.498, p = 0.036), postoperative serum creatinine (r = 0.567, p < 0.010), and length of hospital stay (r = 0.722, p < 0.0001). Importantly, uL-FABP at baseline (AUC = 0.77, 95% CI: 0.64-0.89, n = 365), 2 h (AUC = 0.71, 95% CI: 0.52-0.90, n = 509), and 6 h (AUC = 0.76, 95% CI: 0.72-0.80, n = 509) diagnosed CPB-AKI earlier. Hence, higher uL-FABP levels associate with worse clinical parameters and may diagnose and predict CPB-AKI earlier.

Restoring glomerular filtration rate by sulforaphane modulates ERK1/2/JNK/p38MAPK, IRF3/iNOS, Nrf2/HO-1 signaling pathways against folic acid-induced acute renal injury in rats

BACKGROUND

Folic acid (FA)-induced acute renal injury (AKI) is a commonly and highly reproducible model used to study AKI. The current study aims to evaluate the possible protective effects of sulforaphane (SFN) against FA-induced renal damage and explore the underlying molecular mechanism.

METHODS

The animals were divided into four groups (6 rats/group) as follows: normal group (received vehicle, p.o.), FA group (received 250 mg/kg, i.p.), SFN low dose group (received 15 mg/kg, p.o. plus FA 250 mg/kg, i.p.), SFN high dose group (30 mg/kg, p.o. plus FA 250 mg/kg, i.p.). At the end of the experiment, serum samples and kidney tissues were obtained to perform biochemical, molecular, and histopathological investigations.

RESULTS

The present study showed that FA-caused AKI was confirmed by a significant elevation of kidney function biomarkers serum levels accompanied by an observation of histopathologic changes. Interestingly, SFN-administration significantly improved kidney function, reduced oxidative stress markers; MDA, NADPH oxidase, MPO, iNOS with up-regulation of GSH, GCLM, GPX4, SOD, NQO1, HO-1 and Nrf2 levels. SFN also downregulated proinflammatory markers. The results also demonstrated the anti-apoptotic effect of SFN through its ability to increase the antiapoptotic Bcl-2 protein and to decrease caspase-3. Moreover, SFN significantly decreased the relative expression of JNK, ERK-1/2, IRF3, and p38MAPK as compared to the FA-nephrotoxic group.

CONCLUSION

The present study revealed that SFN possess an antioxidant, anti-inflammatory and antiapoptotic activity by modulating caspase-3, Bcl-2, ERK1/2, JNK, GCLM, NQO1, GPX4, Nrf2, HO-1 and P38 signaling pathways in a dose dependent manner which provides a potential therapeutic strategy for preventing FA-induced AKI.

Serum soluble triggering receptor levels expressed on myeloid cells2 identify early acute kidney injury in infants and young children after pediatric cardiopulmonary bypass

Background

Acute kidney injury (AKI) is a potential complication after cardiopulmonary bypass (CPB) of pediatric cardiac surgery and contributes to a certain amount of perioperative mortality. Serum soluble triggering receptor expressed on myeloid cells2 (sTREM2) is an inflammation-associated cytokine in circulation. Alterations of sTREM2 level have been reported in Alzheimer's disease, sepsis, and some other pathologic conditions. This study aimed to investigate the role of sTREM2 as a forecasting factor for AKI in infants and young children and other factors associated with early renal injury after pediatric CPB.

Methods

A prospective cohort study with consecutive infants and young children ≤ 3 years old undergoing CPB from September 2021 to August 2022 was conducted in an affiliated university children's hospital. These patients were divided into an AKI group (n = 10) and a non-AKI group (n = 60). Children's characteristics and clinical data were measured. Perioperative sTREM2 levels were analyzed with enzyme-linked immunosorbent assay (ELISA).

Results

In children developing AKI, the sTREM2 levels significantly decreased at the beginning of CPB compared to the non-AKI group. Based on binary logistic regression analysis and multivariable regression analysis, risk-adjusted classification for congenital heart surgery (RACHS-1), operation time, and the s-TREM2 level at the beginning of CPB (AUC = 0.839, p = 0.001, optimal cut-off value: 716.0 pg/ml) had predictive value for post-CPB AKI. When combining the sTREM2 level at the beginning of CPB and other indicators together, the area under the ROC curve enlarged.

Conclusions

Operation time, RACHS-1 score, and sTREM2 level at the beginning of CPB were independent prognosis factors of post-CPB AKI in infants and young children ≤ 3 years old. Decreased sTREM2 identified post-CPB AKI, and ultimately hampered the outcomes. Our findings indicated that sTREM2 may be a protective factor for AKI after CPB in infants and young children ≤ 3 years old.

Association of Urine Biomarkers With Acute Kidney Injury and Fluid Overload in Infants After Cardiac Surgery: A Single Center Ancillary Cohort of the Steroids to Reduce Systemic Inflammation After Infant Heart Surgery Trial

To examine the association between three perioperative urine biomarker concentrations (urine cystatin C [uCysC], urine neutrophil gelatinase-associated lipocalin [uNGAL], and urine kidney injury molecule 1 [uKIM-1]), and cardiac surgery-associated acute kidney injury (CS-AKI) and fluid overload (FO) in infants with congenital heart disease undergoing surgery on cardiopulmonary bypass. To explore how urine biomarkers are associated with distinct CS-AKI phenotypes based on FO status.

DESIGN

Ancillary prospective cohort study.

SETTING

Single U.S. pediatric cardiac ICU.

PATIENTS

Infants less than 1 year old enrolled in the Steroids to Reduce Systemic Inflammation after Infant Heart Surgery trial (NCT03229538) who underwent heart surgery from June 2019 to May 2020 and opted into biomarker collection at a single center. Infants with preoperative CS-AKI were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Forty infants met inclusion criteria. Median (interquartile) age at surgery was 103 days (5.5-161 d). Modified Kidney Disease Improving Global Outcomes-defined CS-AKI was diagnosed in 22 (55%) infants and 21 (53%) developed FO. UCysC and uNGAL peaked in the early postoperative period and uKIM-1 peaked later. In unadjusted analysis, bypass time was longer, and Vasoactive-Inotropic Score at 24 hours was higher in infants with CS-AKI. On multivariable analysis, higher uCysC (odds ratio [OR], 1.023; 95% CI, 1.004-1.042) and uNGAL (OR, 1.019; 95% CI, 1.004-1.035) at 0-8 hours post-bypass were associated with FO. UCysC, uNGAL, and uKIM-1 did not significantly correlate with CS-AKI. In exploratory analyses of CS-AKI phenotypes, uCysC and uNGAL were highest in CS-AKI+/FO+ infants.

CONCLUSIONS

In this study, uCysC and uNGAL in the early postoperative period were associated with FO at 48 hours. UCysC, uNGAL, and uKIM-1 were not associated with CS-AKI. Further studies should focus on defining expected concentrations of these biomarkers, exploring CS-AKI phenotypes and outcomes, and establishing clinically meaningful endpoints for infants post-cardiac surgery.

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.

Utility of urinary liver-type fatty acid-binding protein as a prognostic marker in adult congenital heart patients hospitalized for acute heart failure

Progression to acute kidney injury (AKI) under treatment in adult congenital heart disease (ACHD) patients with heart failure is associated with poor prognosis, early detection and interventions are necessary. We aimed to explore the utility of urinary liver-type fatty acid binding protein (L-FABP) in ACHD patients hospitalized for acute decompensated heart failure (ADHF). We prospectively evaluated hemodynamic, biochemical data, and urinary biomarkers including urinary L-FABP in ACHD patients hospitalized in our institution from June 2019 to March 2022. The primary outcomes were the development of AKI and death. AKI was defined as serum creatinine level increased by 0.3 mg/dl or more within 5 days after hospitalization. A total of 104 ADHF patients aged 31 (36-51) years were enrolled. 26 cases (25% of ADHF patients) developed AKI during hospitalization and 4 died after hospital discharge. Serum creatinine (sCr), serum total bilirubin, brain natriuretic peptide (BNP), and urinary L-FABP in AKI patients were significantly higher than in non-AKI patients, whereas systemic oxygen saturation of the peripheral artery (SpO₂) and estimated glomerular filtration ratio in AKI patients were lower than non-AKI patients. There was no difference in the intravenous diuretic dose on admission and during hospitalization between the two groups. In the receiver operating characteristic (ROC) analysis, the maximum area under the curve (AUC) of urinary biomarkers in AKI patients was urinary L-FABP (AUC = 0.769, p < 0.001) with a cutoff value of 4.86 µg/gCr. Urinary L-FABP level on admission was associated with a predictor for AKI development during hospitalization after adjusting for sCr, BNP and SpO₂. Urinary L-FABP was a useful predictor for the development of AKI in ACHD patients hospitalized for ADHF. Monitoring of urinary L-FABP allows us to detect a high-risk patient earlier than the conventional biomarkers.

Predictive value of neutrophil gelatinase-associated lipocalin in children with acute kidney injury: A systematic review and meta-analysis

Purpose

Neutrophil gelatin lipase carrier protein (NGAL) has been used as an early biomarker to predict acute kidney injury (AKI). However, the predictive value of NGAL in urine and blood in children with acute kidney injury in different backgrounds remains unclear. Therefore, we conducted this systematic review and meta-analysis to explore the clinical value of NGAL in predicting AKI in children.

Methods

Computerized databases were searched for relevant the studies published through August 4th, 2022, which included PUBMED, EMBASE, COCHRANE and Web of science. The risk of bias of the original included studies was assessed by using the Quality Assessment of Studies for Diagnostic Accuracy (QUADA-2). At the same time, subgroup analysis of these data was carried out.

Results

Fifty-three studies were included in this meta-analysis, involving 5,049 patients, 1,861 of whom were AKI patients. The sensitivity and specificity of blood NGAL for predicting AKI were 0.79 (95% CI: 0.69-0.86) and 0.85 (95% CI: 0.75-0.91), respectively, and SROC was 0.89 (95% CI: 0.86-0.91). The sensitivity and specificity of urine NGAL for predicting AKI were 0.83 (95% CI: 0.78-0.87) and 0.81 (95% CI: 0.77-0.85), respectively, and SROC was 0.89 (95% CI: 0.86-0.91). Meanwhile, the sensitivity and specificity of overall NGAL (urine and blood NGAL) for predicting AKI in children were 0.82 (95% CI: 0.77-0.86) and 0.82 (95% CI: 0.78-0.86), respectively, and SROC was 0.89 (95% CI: 0.86-0.91).

Conclusion

NGAL is a valuable predictor for AKI in children under different backgrounds. There is no significant difference in the prediction accuracy between urine NGAL and blood NGAL, and there is also no significant difference in different measurement methods of NGAL. Hence, NGAL is a non-invasive option in clinical practice. Based on the current evidence, the accuracy of NGAL measurement is the best at 2 h after cardiopulmonary bypass (CPB) and 24 h after birth in asphyxiated newborns.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42022360157.

The Use of Renal Biomarkers in Pediatric Cardiac Patients With Acute Kidney Injury

Acute kidney injury (AKI) is a common and serious condition that occurs in approximately 30% to 50% of pediatric patients that undergo cardiac surgery. Currently used parameters to measure kidney function (serum creatinine and urine output) are often unreliable and delay the prediction of AKI, despite their adoption into clinical guidelines. Emerging evidence suggests that biomarkers such as neutrophil gelatinase-associated lipocalin, cystatin C, interleukin-18, kidney injury molecule 1, and liver-type fatty acid– binding protein may be useful in the identification and location of pediatric renal injury. Ontogeny-related changes in tubular function and nephrogenesis result in reference values that differ based on age and sex. In addition, changes in endogenous concentrations may result from factors such as cardiopulmonary bypass. The use of urine samples to measure renal biomarkers offers a significant advantage compared with routine blood sampling, especially in the neonatal patient population. Future research is warranted to determine age-dependent changes in AKI biomarkers and the relationship with pharmacokinetic clearance of commonly used medications in the postoperative cardiac patient.

Prediction value of regional oxygen saturation in intestine and kidney for acute kidney injury in children with congenital heart disease after surgery

OBJECTIVE

To study the prediction value of regional oxygen saturation (rSO ₂) in brain, intestine and kidney for acute kidney injury (AKI) in children with congenital heart disease after surgery.

METHODS

Fifty-seven children with congenital heart disease (CHD), whose weight >2.5 kg and age≤1 year were treated in Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine from January 2020 to December 2020. The rSO ₂ of brain, intestine and kidney were monitored with near-infrared spectroscopy continuously for 48 h after surgery. The predictive values of cerebral, intestinal and renal rSO ₂ for occurrence and severity of postoperative AKI were analyzed.

RESULTS

Among 57 patients, postoperative AKI developed in 38 cases (66.7%), including 18 cases of AKI-1 (47.4%), 9 cases of AKI-2 (23.7%) and 11 cases of AKI-3 (28.9%). There was no significant difference in cerebral rSO ₂ between AKI group and non-AKI group ( F=0.012, P>0.05), while the intestinal rSO ₂ and renal rSO ₂ in AKI group were significantly lower than those in non-AKI group ( F=5.017 and 5.003, both P<0.05). There was no significant difference in brain rSO ₂ between children with or without AKI-2 and above ( F=0.311, P>0.05), but the intestinal rSO ₂ and renal rSO ₂ in children with AKI-2 and above were lower than other children ( F=6.431 and 14.139, both P<0.05). The area under ROC curve (AUC) of intestinal rSO ₂ 3 h after surgery for predicting AKI was 0.823, and with intestinal rSO ₂ 3 h after surgery <85%, the sensitivity and specificity were 66.7% and 89.5%, respectively. The AUC of renal rSO ₂ for the diagnosis of AKI at 31 h after surgery was 0.918, and with intestinal rSO ₂ 31 h after surgery <84%, the sensitivity and specificity were 72.2% and 84.2%, respectively. The AUC of intestinal rSO ₂3 h after surgery for the diagnosis of AKI-2 and above was 0.829, and with intestinal rSO ₂ 3 h after surgery <84%, the sensitivity and specificity were 62.2% and 90.0%, respectively. The AUC of renal rSO ₂ for the diagnosis of AKI-2 and above was 0.826 at 34 h postoperatively, and with intestinal rSO ₂ 34 h after surgery <71%, the sensitivity and specificity were 91.9% and 55.0%, respectively.

CONCLUSION

The monitoring of intestinal and renal rSO ₂ can predict the occurrence and severity of postoperative AKI in children with congenital heart disease after surgery.

Prognostic factors in children with acute fulminant myocarditis receiving venoarterial extracorporeal membrane oxygenation

Background

Pediatric acute fulminant myocarditis (AFM) is a very dangerous disease that may lead to acute heart failure or even sudden death. Previous reports have identified some prognostic factors in adult AFM; however, there is no such research on children with AFM on venoarterial extracorporeal membrane oxygenation (VA-ECMO). This study aimed to find relevant prognostic factors for predicting adverse clinical outcomes.

Methods

A retrospective analysis was performed in an affiliated university children’s hospital with consecutive patients receiving VA-ECMO for AFM from July 2010 to November 2020. These children were classified into a survivor group (n=33) and a non-survivor group (n=8). Patient demographics, clinical events, laboratory findings, and electrocardiographic and echocardiographic parameters were analyzed.

Results

Peak serum creatinine (SCr) and peak creatine kinase isoenzyme MB during ECMO had joint predictive value for in-hospital mortality (p=0.011, AUC=0.962). Based on multivariable logistic regression analysis, peak SCr level during ECMO support was an independent predictor of in-hospital mortality (OR=1.035, 95% CI 1.006 to 1.064, p=0.017, AUC=0.936, with optimal cut-off value of 78 μmol/L).

Conclusion

Tissue hypoperfusion and consequent end-organ damage ultimately hampered the outcomes. The need for left atrial decompression indicated a sicker patient on ECMO and introduced additional risk for complications. Earlier and more cautious deployment would likely be associated with decreased risk of complications and mortality.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Combination of SOFA Score and Urinary NGAL May Be an Effective Predictor for Ventilator Dependence among Critically Ill Surgical Patients: A Pilot Study

Background: Ventilator dependence (VD) has been considered as a serious complication in critically ill patients in the intensive care unit (ICU). Acute kidney injury (AKI) is associated with VD as a result of lung–kidney interaction. The aim of our study was to investigate novel biomarkers in predicting ventilator dependence in critically ill surgical patients. Methods: Patients who were admitted to surgical ICU were enrolled and their serum and urine samples were collected. Novel biomarkers including gelatinase-associated lipocalin (NGAL), calprotectin, kidney injury molecule-1 (KIM-1), cystatin C, and growth differentiation factor 15 (GDF-15) were analyzed and correlated with clinical outcome. Results: A total of 33 patients were enrolled and analyzed. The majority of them received abdominal surgery prior to ICU admission. Thirteen patients were classified into the VD group, while the remaining 20 were in a non-ventilator dependence group (nVD). Statistical analysis demonstrated that the following were significantly higher in the VD group than in the nVD group: serum NGAL (420.25 ± 45.18 ng/mL vs. 314.68 ± 38.12 ng/mL, p-value 0.036), urinary NGAL (420.87 ± 41.08 ng/mL vs. 250.84 ± 39.45 ng/mL, p-value 0.002), SOFA score (11.3 ± 1.5 vs. 5.6 ± 0.7, p-value 0.001), and APACHE II score (23.2 ± 2.6 vs. 13.6 ± 0.8, p-value 0.001). The area under the ROC curve (AUROC) of urinary NGAL for VD was 0.808. The combination of urinary NGAL and SOFA score could further increase AUROC for VD to 0.835. Conclusions: The current study demonstrated the predictive capability of urinary NGAL for ventilator dependence among critically ill surgical patients. When combined with SOFA score, the predictive ability was further augmented. Further large-scale studies are warranted to validate our findings.

Acute Kidney Injury in Critically Ill Children Is Not all Acute: Lessons Over the Last 5 Years

Acute kidney injury (AKI) in the pediatric intensive care unit (PICU) is an important risk factor for increased morbidity and mortality during hospitalization. Over the past decade, accumulated data on children and young people indicates that acute episodes of kidney dysfunction can have lasting consequences on multiple organ systems and health outcomes. To date, there are no guidelines for follow-up of surviving children that may be at risk of long-term sequelae following AKI in the PICU. This narrative review aims to describe literature from the last 5 years on the risk of medium and long-term kidney and non-kidney outcomes after AKI in the PICU. More specifically, we will focus on outcomes in children and young people following AKI in the general PICU population and children undergoing cardiac surgery. These outcomes include mortality, hypertension, proteinuria, chronic kidney disease, and healthcare utilization. We also aim to highlight current gaps in knowledge in medium and long-term outcomes in this pediatric population. We suggest a framework for future research to develop evidence-based guidelines for follow-up of children surviving an episode of critical illness and AKI.

Goal-directed perfusion to reduce acute kidney injury after paediatric cardiac surgery (GDP-AKIp): study protocol for a prospective randomised controlled trial

INTRODUCTION

Cardiac surgery-associated acute kidney injury (CS-AKI) occurs in up to 40%~60% of paediatric patients and increases postoperative morbidity and mortality. A goal-directed perfusion (GDP) strategy aimed at maintaining indexed oxygen delivery (DO₂i) above the critical threshold (reported to be 260~300 mL/min/m² in adults) during cardiopulmonary bypass (CPB), is effective in reducing the incidence of CS-AKI. However, no clear standards of paediatric critical DO₂i exist. Our prior prospective cohort study exploring the critical DO₂i threshold during paediatric CPB has found the nadir DO₂i <353 mL/min/m² was an independent risk predictor of CS-AKI. Based on this background, this trial is designed to further determine whether the implementation of the GDP initiative aimed at maintaining DO₂i ≥360 mL/min/m² would reduce the rate of CS-AKI in paediatrics and improve clinical outcome.

METHODS AND ANALYSIS

This is a prospective, single-centre, randomised controlled trial. In total, 166 paediatric patients undergoing cardiac surgery will be randomly allocated to the GDP group or control group. Patients in the GDP arm will be treated with a GDP strategy during CPB aimed to maintain DO₂i at ≥360 mL/min/m² (to ensure safely above the risk DO₂i threshold we found). The perfusion strategy for patients in the control arm will be factored on body surface area and temperature. The primary outcome is the rate of postoperative CS-AKI (it is defined according to paediatric Risk, Injury, Failure, Loss of renal function and End-stage renal disease criteria). The secondary end points include: (1) the other oxygen metabolism parameters during CPB; (2) major complication and all-cause mortality (in-hospital or within 30 days postoperatively); (3) short-term clinical outcomes (ie, time to extubation, mechanical ventilation time, hospital stay).

ETHICS AND DISSEMINATION

The study has been approved by the Biomedical Research Ethics committee of West China Hospital of Sichuan University (approval number: 2019(863)). Results will be disseminated through peer-reviewed publications and conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2000029232.

New insights into the pathophysiological mechanisms underlying cardiorenal syndrome

Communication between the heart and kidney occurs through various bidirectional pathways. The heart maintains continuous blood flow through the kidney while the kidney regulates blood volume thereby allowing the heart to pump effectively. Cardiorenal syndrome (CRS) is a pathologic condition in which acute or chronic dysfunction of the heart or kidney induces acute or chronic dysfunction of the other organ. CRS type 3 (CRS-3) is defined as acute kidney injury (AKI)-mediated cardiac dysfunction. AKI is common among critically ill patients and correlates with increased mortality and morbidity. Acute cardiac dysfunction has been observed in over 50% of patients with severe AKI and results in poorer clinical outcomes than heart or renal dysfunction alone. In this review, we describe the pathophysiological mechanisms responsible for AKI-induced cardiac dysfunction. Additionally, we discuss current approaches in the management of patients with CRS-3 and the development of targeted therapeutics. Finally, we summarize current challenges in diagnosing mild cardiac dysfunction following AKI and in understanding CRS-3 etiology.