(137) How Neutrophil Extracellular Traps Affect Acute Kidney Injury After Pediatric Cardiopulmonary Bypass

Introduction: Neutrophil extracellular traps (NETs) result from an alternative neutrophil cell death pathway formed in response to inflammatory stimuli. Excessive NET formation is associated with endothelial damage and end organ injury. Inflammation as a result of cardiopulmonary bypass (CPB) is well described. Acute kidney injury (AKI) is associated with worse pediatric outcomes after CPB including mortality and ICU length of stay. NETs are implicated in post-CPB AKI in adults. The association between NETs and pediatric AKI after CPB remains unknown. This study examines preoperative NET levels in post-CPB AKI in pediatrics, to investigate if NETs may be used as an early biomarker of disease.

Methods: This prospective observational cohort study included pediatric patients undergoing CPB at a single center between 2022-2023. Patients were excluded if they were on preoperative mechanical support (ECMO or VAD). Pre-cardiopulmonary bypass samples were collected, and myeloperoxidase (MPO)-DNA complexes, a specific marker for NETs, were measured via enzyme-linked immunosorbent assay (ELISA). MPO-DNA complexes were normalized to healthy controls. Data was collected via the Pediatric Critical Care Consortium (PC4) database and medical chart review. Markers of AKI were assessed via univariate analysis and Spearman Rank Correlations.

Results: Out of a total of 85 patients, there were 16 neonates (0-30 days), 33 infants (31 days-1 year) and 36 children (1-18 years). Neonates had significantly higher preoperative levels of NETs compared to infants and children (p < 0.001). Increased postoperative creatinine was also highest in neonates (p=0.03). Preoperative NET levels were not associated with postoperative lowest urine output (r=0.01, p=0.93) or days to first negative fluid balance (r=0.08, p=0.45). While not statistically significant, there was a trend towards positive correlation between preoperative NET levels and increased postoperative creatinine (r=0.2, p=0.104).

Conclusions: Preoperative NET levels were not associated with markers of post-CPB AKI in this study. As preoperative NET levels and increased postoperative creatinine were higher in neonates, closer evaluation of this particularly vulnerable patient population warrants further investigation.