Preoperative Serum Ferritin Level and Acute Kidney Injury after Pediatric Cardiac Surgery
Authors: Cao Liang , Xiong Chao , Bie Dongyun , Jia Yuan , Yuan Su , Wang Jianhui 
Published: December 2024

Background

Acute kidney injury (AKI) is a significant complication in pediatric patients undergoing cardiac surgery. Iron metabolism-related indicators such as ferritin may predict AKI after adult cardiac surgery. However, it remains unclear whether ferritin can be used as a predictor of AKI after pediatric cardiac surgery. This study aims to investigate the association between preoperative serum ferritin levels and the risk of AKI in pediatric population.

Methods

A prospective observational cohort study included 6088 pediatric patients (aged <16 years) who underwent cardiac surgery between 2022 and 2023 in Fuwai hospital. Preoperative serum ferritin levels were measured. The primary outcome was the occurrence of AKI within 7 days postoperatively, diagnosed per KDIGO criteria. Secondary outcomes included severe AKI (KDIGO stages 2 and 3), postoperative dialysis, and in-hospital mortality.

Results

The preoperative serum ferritin demonstrated a J-shaped association with the occurrence of AKI. Categorically, higher serum ferritin levels (>300 μ g/L, 150-300 μ g/L and 80.6-150 μ g/L) significantly increased the risk of AKI compared to lower level (40-80.6 μ g/L) (adjusted OR, 3.468; 95% CI, 1.911-6.291; adjusted OR, 3.142; 95% CI, 2.037-4.8451; and adjusted OR, 1.880; 95% CI, 1.299-2.495; respectively). The risk of stage 2 and stage 3 AKI significantly increased with higher serum ferritin categories compared to lower level (adjusted OR, 4.428; 95% CI, 1.631-12.026; adjusted OR, 3.707; 95% CI, 1.710-8.035; and adjusted OR, 2.345; 95% CI, 1.220-4.505; respectively). As a continuous variable, consistent with categorical variables, elevated serum ferritin levels (>80.6μg/L) independently predicted AKI (adjusted OR, 1.001; 95% CI, 1.000-1.002).

Conclusions

This study highlights the importance of preoperative serum ferritin levels in predicting AKI risk in pediatric patients undergoing cardiac surgery. Further research is warranted to elucidate the underlying mechanisms and explore the therapeutic implications of ferritin monitoring in clinical practice.

Registration

URL:https://www.clinicaltrials.gov; Unique identifier:NCT05489263.

Clinical Perspective

What Is New?

An important role for iron metabolism in the pathogenesis of AKI has long been appreciated. Inflammatory factors and hemodynamic and the release of labile iron, contributing to oxidation from reactive oxygen species are among the major determinants of CSA-AKI. This study highlights the importance of preoperative serum ferritin levels in predicting AKI risk in pediatric patients undergoing cardiac surgery.

In this prospective observational cohort study included 3703 pediatric patients, who developed AKI had significantly higher concentrations of preoperative serum ferritin. The elevated serum ferritin levels exceeding 80.6μg/L were significantly correlated with AKI and severe AKI. This study highlights elevated preoperative serum ferritin level is an early warning indicator of CSA-AKI.

What Are the Clinical Implications?

Among pediatric patients undergoing cardiac surgery, serum creatine delayed diagnose of AKI. This study is the first to establish a relationship between elevated serum ferritin levels and CSA-AKI in a substantial pediatric population, thereby offering novel insights into AKI mechanisms within this demographic.

Early elevation of serum ferritin may serve as an early warning sign for AKI development in pediatric patients, with implications for utilizing ferritin as a biomarker to stratify AKI risk and exploring iron chelation therapy as a preventive measure.

Abbreviated legend for Central Picture