Limitations of Early Serum Creatinine Variations for the Assessment of Kidney Injury in Neonates and Infants with Cardiac Surgery

Abstract

BackgroundChanges in kidney function, as assessed by early and even small variations in serum creatinine (ΔsCr), affect survival in adults following cardiac surgery but such associations have not been reported in infants. This raises the question of the adequate assessment of kidney function by early ΔsCr in infants undergoing cardiac surgery.MethodologyThe ability of ΔsCr within 2 days of surgery to assess the severity of kidney injury, accounted for by the risk of 30-day mortality, was explored retrospectively in 1019 consecutive neonates and infants. Patients aged ≤ 10 days were analyzed separately because of the physiological improvement in glomerular filtration early after birth. The Kml algorithm, an implementation of k-means for longitudinal data, was used to describe creatinine kinetics, and the receiver operating characteristic and the reclassification methodology to assess discrimination and the predictive ability of the risk of death.ResultsThree clusters of ΔsCr were identified: in 50% of all patients creatinine decreased, in 41.4% it increased slightly, and in 8.6% it rose abruptly. Mortality rates were not significantly different between the first and second clusters, 1.6% [0.0–4.1] vs 5.9% [1.9–10.9], respectively, in patients aged ≤ 10 days, and 1.6% [0.5–3.0] vs 3.8% [1.9–6.0] in older ones. Mortality rates were significantly higher when creatinine rose abruptly, 30.3% [15.1–46.2] in patients aged ≤ 10 days, and 15.1% [5.9–25.5] in older ones. However, only 41.3% of all patients who died had an abrupt increase in creatinine. ΔsCr improved prediction in survivors, but not in patients who died, and did not improve discrimination over a clinical mortality model.ConclusionsThe present results suggest that a postoperative decrease in creatinine represents the normal course in neonates and infants with cardiac surgery, and that early creatinine variations lack sensitivity for the assessment of the severity of kidney injury.

Acute kidney injury after pediatric cardiac surgery

“…41 According to a recent investigation, abrupt postoperative variation of SCr (DSCr) is also a nonsensitive marker because of its delayed rise and lack of differential function between survivors and deceased. 42…”

Does acute normovolemic hemodilution affect intraoperative value of serum-creatinine concentration in patients undergoing cardiac surgery

“…S-Cr increases due to acute tubular necrosis and subsequent reduction in glomerular filtration rate (GFR), which results in 50% loss of glomerular function [12][13][14]. Contrarily, The present study showed that ANH-induced hemodilution, which replaces whole blood by 5% HES of 5 ml/kg, does not affect neither s-Cr values nor, consequently, compromise the clinical efficacy of s-Cr.…”

Early Postoperative Serum Creatinine Adjusted for Fluid Balance Precisely Predicts Subsequent Acute Kidney Injury After Cardiac Surgery

“…As a standard surrogate of kidney function, SCr has been used widely in diagnosing and staging AKI despite its limitations. 29,30 Furthermore, relative changes of early SCr also might be one of the indicators for the subsequent development of AKI and poor outcomes. Previous studies have demonstrated the relationship between minimal changes of SCr as predictors for later AKI and overall outcomes in cardiac surgery patients.…”