Early postoperative serum cystatin C predicts severe acute kidney injury following pediatric cardiac surgery

Abstract

In this multicenter, prospective study of 288 children (half under 2 years of age) undergoing cardiac surgery, we evaluated whether the measurement of pre- and postoperative serum cystatin C (CysC) improves the prediction of acute kidney injury (AKI) over that obtained by serum creatinine (SCr). Higher preoperative SCr-based estimated glomerular filtration rates predicted higher risk of the postoperative primary outcomes of stage 1 and 2 AKI (adjusted odds ratios (ORs) 1.5 and 1.9, respectively). Preoperative CysC was not associated with AKI. The highest quintile of postoperative (within 6 h) CysC predicted stage 1 and 2 AKI (adjusted ORs of 6 and 17.2, respectively). The highest tertile of percent change in CysC independently predicted AKI, whereas the highest tertile of SCr predicted stage 1 but not stage 2 AKI. Postoperative CysC levels independently predicted longer duration of ventilation and intensive care unit length of stay, whereas the postoperative SCr change only predicted longer intensive care unit stay. Thus, postoperative serum CysC is useful to risk-stratify patients for AKI treatment trials. More research, however, is needed to understand the relation between preoperative renal function and the risk of AKI.

Figures

Figure 1. Plotted glomerular filtration rate (GFR) percentile values for subjects less than 2 years old

Displays the percentile curves for GFR derived from normal children from infancy to young adulthood. Individual preoperative estimated GFR (eGFR) of subjects from this study are plotted on the curves (+). To the right of the graph, the value for each percentile (Pct) curve shown.

Figure 2. Association of postoperative serum creatinine (SCr) and cystatin C (CysC) with duration of ventilation

Displays mean duration of mechanical ventilation (days) for the (a) quintiles of first postoperative CysC concentrations, (b) tertiles of first postoperative percent CystC change and (c) tertiles of first postoperative percent SCr change from baseline. Standard errors were extremely low (ranging from 0.01 to 0.04, and are not displayed). Univariate P-values for test of linear trend are displayed.