Acute Kidney Injury After Pediatric Cardiac Surgery

Syndecan-1 as a Biomarker for Fluid Overload After High-Risk Pediatric Cardiac Surgery: A Pilot Study

OBJECTIVE

Fluid overload (FO) after pediatric cardiac surgery with cardiopulmonary bypass (CPB) is common and has been associated with poor outcomes. We aimed to describe the relationship between plasma concentrations of syndecan-1 (SD1), a biomarker of endothelial glycocalyx injury, and FO in a cohort of children undergoing cardiac surgery.

DESIGN

Single-center prospective observational pilot study, 2022-2023.

SETTING

Twenty-six-bed pediatric cardiac ICU (CICU) at a quaternary pediatric referral center.

PATIENTS

Children younger than 18 years old undergoing Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery congenital heart surgery mortality category 3, 4, and 5 cardiac surgeries with CPB.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We enrolled 15 patients. Blood samples were collected preoperatively and 4 hours postoperatively, then processed for plasma. SD1 concentrations were measured using enzyme-linked immunosorbent assays and compared with fluid balance on postoperative days (PODs) 1, 2, 3, and peak. SD1 discriminated fluid balance of greater than or equal to 10% on POD-1, POD-2, and POD-3 with an area under the receiver operating characteristic curve (AUROC) of 0.74, 0.84, and 0.88, respectively. SD1 also discriminated peak fluid balance of greater than or equal to 10% occurring on any day over the first seven PODs with an AUROC of 0.94. Patients with greater than or equal to 10% fluid balance on POD-2 (p = 0.037), POD-3 (p = 0.020), or peak (p = 0.021) had significantly elevated delta SD1 when compared with those reaching less than 10%. Fluid balance of greater than or equal to 10% on POD-2 was associated with adverse events including longer duration of mechanical ventilation and CICU stay.

CONCLUSIONS

Plasma SD1 was associated with FO in pediatric patients undergoing high-risk cardiac surgery with CPB. Further studies exploring the clinical utility of SD1 as a biomarker for FO in the postoperative management of children who undergo cardiac surgery with CPB should be pursued.

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.

Association between plasma-free haemoglobin and postoperative acute kidney injury in paediatric cardiac surgery: a prospective observational study

Background

Acute kidney injury (AKI) is a common complication among patients requiring cardiopulmonary bypass (CPB) during paediatric cardiac surgery. Plasma-free haemoglobin (PFH) produced by haemolysis during CPB contributes to AKI. This study aimed to determine the association between PFH and postoperative AKI during paediatric cardiac surgery requiring CPB.

Methods

This prospective, single-centre, observational study included children aged <5 yr who underwent cardiac surgery requiring CPB. PFH was measured pre-CPB, every 30 min during CPB, after modified ultrafiltration, on ICU admission, and once a day at 1-3 days after surgery. The study outcome included the relationship between peak PFH concentrations and the development of postoperative AKI up to 3 days after surgery. Additionally, multivariable analysis was performed to determine the risk factors for AKI.

Results

Of 179 patients, 74 (41%) developed postoperative AKI. Patients who developed AKI had significantly higher peak PFH concentrations (80 mg dl-1 [inter-quartile range, 50-132.5] vs 60 mg dl-1 [40-100]; P=0.006). Multivariable analysis did not identify peak PFH concentrations as an independent risk factor for postoperative AKI (odds ratio [OR] 1.00; 95% confidence interval [CI]: 0.99-1.00; P=0.268). Factors associated with postoperative AKI were age in months (OR 0.96; 95% CI: 0.94-0.99; P=0.007) and CPB duration (OR 1.02; 95% CI: 1.01-1.02; P<0.001).

Conclusions

There was an association between postoperative AKI and CPB time rather than PFH. Perioperative peak PFH concentrations were significantly higher in patients with postoperative AKI after paediatric cardiac surgery requiring CPB.

Association between postoperative ibuprofen exposure and acute kidney injury after pediatric cardiac surgery

BACKGROUND

Acute kidney injury (AKI) is a common complication after pediatric cardiac surgery and is associated with worse outcomes. Ibuprofen is widely used in the perioperative period and can affect kidney function in children. However, the association between ibuprofen exposure and AKI after pediatric cardiac surgery has not been determined yet.

METHODS

In this retrospective cohort study, children undergoing cardiac surgery with cardiopulmonary bypass were studied. Exposure was defined as given ibuprofen in the first 7 days after surgery. Postoperative AKI was diagnosed using the KDIGO criteria. A multivariable Cox regression model was used to assess the association between ibuprofen exposure and postoperative AKI by taking ibuprofen as a time-varying covariate.

RESULTS

Among 1,112 included children, 198 of them (17.8%) experienced AKI. In total, 396 children (35.6%) were exposed to ibuprofen. AKI occurred less frequently among children who were administered ibuprofen than among those who were not (46 of 396 [11.6%] vs. 152 of 716 [21.2%], p < 0.001). Using the Cox regression model accounting for time-varying exposures, ibuprofen treatment was not associated with AKI (adjusted HR, 0.99; 95% CI 0.70-1.39, p = 0.932). This insignificant association was consistent across the sensitivity and subgroup analyses.

CONCLUSIONS

Postoperative ibuprofen exposure in pediatric patients undergoing cardiac surgery was not associated with an increased risk of AKI.

A Clinical Mathematical Model Estimating Postoperative Urine Output in Children Underwent Cardiopulmonary Bypass for Congenital Heart Surgery

Objectives Our objective was to build a proof of concept of the clinical mathematical model estimating postoperative urine output (UOP) utilizing preoperative, intraoperative, and immediate postoperative variables in children who underwent cardiopulmonary bypass (CPB) for congenital heart surgery.

Methods This was a single-center, retrospective cohort study in a university-affiliated children's hospital. Patients younger than 21 years old who underwent CPB for congenital heart surgery and were postoperatively admitted to West Virginia University Children's Hospital's pediatric intensive care unit (PICU) between September 1, 2007 and June 31, 2013 were included in the study. Body surface area, CPB duration, first measured hematocrit, serum pH, central venous pressure, and vasoactive-inotropic score in the PICU were used to build the mathematical model. A randomly selected 50% of the dataset was used to calculate model parameters. A cross-validation was used to assess model performance.

Results A total of 256 patients met the inclusion criteria. The model was able to achieve mean absolute error of 1.065 mL/kg/h (95% confidence interval (CI): 1.062–1.067 mL/kg/h), root mean squared error of 1.80 mL/kg/h (95% CI: 1.799–1.804 mL/kg/h), and R2 of 0.648 (95% CI: 0.646–0.650) in estimating UOP in the first 32 hours of postoperative period.

Conclusions The mathematical model utilizing preoperative, intraoperative, and immediate postoperative variables may be a potentially useful clinical tool in estimating UOP in the first 32 hours postoperative period.