Early Postoperative Cell-Free DNA Reflects Renal and Hepatic Injury After Pediatric Cardiac Surgery

Circulating cell-free DNA (cfDNA) is released during tissue injury and systemic inflammation, but its association with postoperative organ injury following pediatric cardiac surgery remains incompletely defined. We evaluated the relationship between early postoperative cfDNA levels and acute kidney injury (AKI) and biochemical hepatic injury in children undergoing open-heart surgery with cardiopulmonary bypass (CPB). This retrospective observational cohort study included 50 pediatric patients (<18 years) who underwent CPB at a tertiary congenital heart center between 2017 and 2018. Plasma cfDNA concentrations were measured perioperatively, with the 6 h postoperative value analyzed as an early biomarker window. AKI was classified using Kidney Disease: Improving Global Outcomes criteria, and hepatic injury was assessed using serial liver enzyme measurements. cfDNA levels increased significantly within 6 h after CPB and were higher in patients with more severe AKI. Six-hour cfDNA concentrations correlated with postoperative creatinine, urea, alanine aminotransferase, and aspartate aminotransferase. In multivariable regression analyses adjusting for cardiopulmonary bypass duration, aortic cross-clamp time, and preoperative oxygen saturation, cfDNA at 6 h remained independently associated with AKI severity and peak liver enzyme levels. These exploratory findings suggest that early postoperative cfDNA elevation is associated with AKI severity and biochemical hepatic injury after pediatric cardiac surgery with CPB. Larger prospective studies are needed to determine its independent predictive value and clinical utility.