(692) Urine Biomarkers, Acute Kidney Injury, and Fluid Overload in Neonatal Cardiac Surgery

Introduction: Acute kidney injury (AKI) and fluid overload (FO) are common after neonatal cardiac surgery on cardiopulmonary bypass and associated with increased morbidity and mortality. Urine biomarkers may permit earlier AKI diagnosis, but their role, time course, and association with FO in neonates is unknown. We describe concentrations of 14 urine biomarkers (cystatin C, neutrophil gelatinase associated lipocalin [NGAL], kidney injury molecule-1 (KIM1), albumin, β-2 microglobulin [β2M], calbindin, clusterin, epidermal growth factor [EGF], osteopontin [OPN], osteoactivin, trefoil factor family-3 (TFF3), uromodulin, vascular endothelial growth factor, and α-glutathione s-transferase [αGST]) at multiple perioperative time points in neonates with congenital heart disease and explore associations with AKI and FO.

Methods: We performed a single-center ancillary prospective cohort study of neonates < 29 days undergoing cardiac surgery and enrolled in the STRESS trial (NCT03229538) from June 2019-May 2020. We excluded preterm neonates and those with preoperative AKI, as defined by the modified KDIGO criteria. Our primary outcome was development of KDIGO-defined AKI. Our secondary outcome was development of ≥10% FO within 48 hours postbypass. Urine samples were collected at 3 time points (preoperative, 0- < 8 hours postbypass, 8-24 hours postbypass). We describe perioperative biomarker values for all neonates, and stratified by AKI and FO.

Results: In our cohort of 13 neonates, 62% developed AKI, all stage 1, and 38% developed FO. The majority of biomarkers peaked in the early postoperative period. In neonates with AKI, β2M (median [standard deviation]; 7760 [5470] v 4420 [4950] ng/mL) and αGST (163 [339] v 12.8 [15.7] ng/mL) were higher in the early postoperative period. In neonates with FO, clusterin (425 [439] v 120 [126] ng/mL), cystatin C (1510 [1080] v 153 [100] ng/mL), OPN (2870 [2310] v 661 [295] ng/mL), NGAL (1310 [1340] v 181 [203] ng/mL), and αGST (281 [433] v 9.77 [11.8] ng/mL) were higher in the early postoperative period.

Conclusions: In a small, single-center cohort, we describe concentrations of 14 urine biomarkers in neonates undergoing cardiac surgery. These data identify typical urine biomarker concentration trends and will inform future studies of their predictive ability for AKI and FO.