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

Acute kidney injury (AKI) is a serious complication of pediatric cardiac surgery, with high morbidity and mortality. We aimed to evaluate the perioperative risk factors for AKI, and the validity of novel diagnostic urinary biomarkers after pediatric cardiac surgery. We analyzed 103 consecutive pediatric patients (≤ 18 years old), who underwent cardiac surgery. AKI was defined by ≥ 50% increase in serum creatinine levels from baseline. Urinary liver-type fatty acid binding protein (L-FABP) and neutrophil gelatinase-associated lipocalin (NGAL) were measured postoperatively at the intensive care unit (ICU) admission, subsequently at 4, 12, and 24 h. Areas under the receiver-operating characteristic curves (AUC) were calculated at each assessment time. AKI had developed in 47 patients (45.6%) by the second postoperative day. Univentricular status, aortic cross-clamping time, and intraoperative fluid balance were independently associated with AKI (p = 0.02, 0.01 and 0.01, respectively). Urinary L-FABP and NGAL were significantly higher in the AKI group at each point (p < 0.05). The predictive abilities of both biomarkers (AUC = 0.78–0.90) at ICU admission and 4 h after were especially high. The patients with L-FABP greater than the cutoff value at ICU admission and 4 h after ICU admission had significantly longer intubation and hospitalization periods (p < 0.05). Those with elevated NGAL levels at admission, and 4 h and 24 h after ICU admission, had significantly longer intubation, ICU stay, and hospitalization (p < 0.05). L-FABP and NGAL can be useful biomarkers for detecting early AKI after pediatric cardiac surgery and predicting adverse clinical outcomes.