Evaluation of acute kidney injury after surgery for congenital heart disease in neonates: a tertiary hospital experience.

Purpose Of The Article: Acute kidney injury (AKI) after cardiac surgery in children with congenital heart disease (CHD) is a serious complication closely associated with high morbidity and mortality. Despite numerous studies on AKI in children, most studies have excluded neonates. We sought to characterize AKI associated with cardiac surgery in neonates, determine its incidence, perioperative and postoperative risk factors, and short-term results.

Materials And Methods: This retrospective study included 177 neonates who were operated on for CHD in our hospital between January 2015 and December 2019. Data of the patients were analyzed according to nKDIGO (neonatal Kidney Disease Improving Global Outcomes) and nRIFLE (neonatal Risk, Injury, Failure, Loss of function, End-stage kidney disease) criteria for evaluating AKI retrospectively. Data of groups with and without AKI were analyzed.

Results: The average age of 177 neonates were 8.2 ± 6.1 (1-28) days. Twenty-two (12.4%) neonates had CS-AKI defined according to nKDIGO criteria. Four (2.3%) neonates reached nKDIGO stage I, 1 (0.6%) reached stage II, 17 (9.6%) reached stage III. Thirty-eight (21.5%) neonates had CS-AKI defined according to nRIFLE criteria. Twenty-four (13.6%) neonates reached nRIFLE stage risk(R), 6 (3.4%) reached stage injury(I), 8 (4.5%) reached stage failure (F). The incidence of cardiac surgery-associated acute kidney injury (CS-AKI) in neonates was 12.5% and 21.5% for nKDIGO and nRIFLE, respectively. The percentage difference between nKDIGO and nRIFLE for AKI assessment was due to the criteria for nRIFLE stage risk(R) urine output < 1.5 mL/kg/h for 24 h. In both classifications, the duration of cardiopulmonary bypass, operation, inotropic treatment, and mechanical ventilation, length of intensive care unit (ICU), and hospital stay were significantly higher in the AKI group than those without AKI group (˂.05). The mortality rate in the groups with AKI was found to be significantly higher (˂.05) than in the groups without AKI. In Kappa analysis, when two classifications were compared according to AKI stages, a significant agreement was found between nKDIGO and nRIFLE classifications (˂.05) (Kappa: 0.299).

Conclusion: AKI and mortality rates were similar between groups according to the nKDIGO and nRIFLE criteria. For early prediction of AKI and adverse outcomes, diagnostic reference intervals might be specified in more detail in neonates undergoing cardiac surgery for CHD.