The clinical outcomes of acute kidney injury substages based on serum cystatin C in pediatric patients undergoing cardiac surgery

BackgroundMultiple biomarkers have been identified by previous studies to diagnose acute kidney injury (AKI). Moreover, combination of biomarkers with conventional criteria to define AKI substages so that we can identify high-risk patients and improve diagnostic accuracy were recommended. Our study aimed to explore the incidence of AKI substages defined by serum cystatin C (CysC), determine whether AKI substages were associated with worse outcomes.MethodsWe prospectively included 2519 pediatric patients (Results507 (20.8%) patients developed SCr-AKI, with 337 (13.8%) in stage 1, 77(3.2%) in stage 2 and 93 (3.8%) in stage 3 respectively. Of the 1925 patients without SCr-AKI, 256 (14.3%) met the definition of sub-AKI. Of the 507 patients with SCr-AKI, 281 (55.4%) patients were defined as AKI substage A, while others (226, 44.6%) were defined as AKI substage B. After adjusting for BSA, neonates, STAT mortality score≥4, previous sternotomy and CPB time>120min, the postoperative LOIS, LOHS and DMV were prolonged with increasing hospitalization expense (PConclusionsOur analysis indicates defining AKI with both CysC and SCr might more significantly affecting clinical outcome associations in pediatric patients undergoing cardiac surgery. Moreover, the serum CysC cutoff of 1.29mg/dL postoperatively is a valuable threshold for AKI risk assessment to define AKI subtypes.