Effect of Urine Output on the Predictive Precision of NephroCheck in On-Pump Cardiac Surgery With Crystalloid Cardioplegia: Insights from the PrevAKI Study.

• According to the manufacturer, an AKIRisk Score value of ≥0.3 identifies patients at high risk for AKI. • Crystalloid cardioplegia may induce high urine output in the hours after cardiac surgery. • There is a significant inverse relationship between urine output and AKIRisk Score. • AKIRisk Score thresholds may require adjustment for urine output. • Early serum creatinine may be superior to AKIRisk Score in predicting subsequent AKI development. Previous studies in other settings suggested that urine output (UO) might affect NephroCheck predictive value. We investigated the correlation between NephroCheck and UO in cardiac surgery patients. Post hoc analysis of a multicenter study. University hospital. Patients who underwent cardiac surgery using cardiopulmonary bypass (CPB) and crystalloid cardioplegia. All patients underwent NephroCheck testing 4 hours after CPB discontinuation. The primary outcome was the correlation between UO, NephroCheck results, and acute kidney injury (AKI, defined according to Kidney Disease: Improving Global Outcomes). Of 354 patients, 337 were included. Median NephroCheck values were 0.06 (ng/mL)²/1,000) for the overall population and 0.15 (ng/mL)²/1,000) for patients with moderate to severe AKI. NephroCheck showed a significant inverse correlation with UO (ρ = −0.17; p = 0.002) at the time of measurement. The area under the receiver characteristic curve (AUROC) for NephroCheck was 0.60 (95% confidence interval [CI], 0.54–0.65), whereas for serum creatinine was 0.82 (95% CI, 0.78–0.86; p < 0.001). When limiting the analysis to the prediction of moderate to severe AKI, NephroCheck had a AUROC of 0.82 (95% CI, 0.77 to 0.86; p<0.0001), while creatinine an AUROC of 0.83 (95% CI, 0.79–0.87; p = 0.001). NephroCheck measured 4 hours after the discontinuation from the CPB predicts moderate to severe AKI. However, a lower threshold may be necessary in patients undergoing cardiac surgery with CPB. Creatinine measured at the same time of the test remains a reliable marker of subsequent development of renal failure. [Display omitted] [ABSTRACT FROM AUTHOR]