European Journal of Molecular & Clinical Medicine

Abstract

Introduction: Acute Kidney Injury (AKI) following surgery for congenital heart disease
with cardiopulmonary bypass (CPB-AKI) is fairly common. Limited studies have compared
newer definitions of AKI in relation to early non-invasive urinary biomarkers for
prediction of post CPB AKI. We sought to evaluate a) incidence using pediatric RIFLE,
AKIN and KDIGO criteria, b) utility of urinary protein creatinine ratio (UPCR), modified
urine microscopy score and NGAL as predictive early AKI biomarkers and c) risk factors
for post CPB-AKI in children with CHD.
Material & Methods: Serial blood and urine samples were collected for all children (2 mo-
18 y) undergoing congenital heart surgery with cardiopulmonary bypass between Nov
2017 to Apr 2019 at pre surgery,6,24, 48 hrs and day 7, day 30. Incidence of AKI was
calculated as per standard definitions. Urine samples were analysed for UPCR
and NGAL in the supernatant and the sediments were microscopically analysed to derive a
modified urine microscopy score. Risk factors predisposing to AKI were analysed by
multivariate analysis. ROC analysis was done for urinary biomarkers taking KDIGO as
gold standard definition of AKI.
Results: Amongst 76 children with CHD, incidence of AKI was 51% with AKIN/KDIGO
criteria and 55% with pRIFLE criteria. Urinary NGAL rose within 6 hrs of CPB. A cut-off
>84 ng/ml had 95% specificity with only 45% sensitivity (AUC-ROC 0.71). At 24 hrs, urine
PCR was significantly high (AUC-ROC 0.7686) while urine microscopy score was similar
in cases who developed AKI. Ventilation >48 hrs, exposure to multiple antibiotics and
sepsis were significantly associated with AKI.
Conclusion: Combination of pRIFLE with AKIN/KDIGO increased detection of post CPB
AKI by 4%. In our cohort urinary NGAL at 6 hours and UPCR at 24 hours had a moderate
predictive value.