Aim: To assess the predictive ability of urinary and plasma biomarkers and clinical routine parameters for subsequent severe fluid overload. Patients & methods: In a pilot study, we studied 100 adult patients after cardiac surgery. On intensive care unit admission, we measured biomarkers in urine (midkine, IL-6, neutrophil gelatinase-associated lipocalin [NGAL], hepcidin-25) and plasma (creatinine, urea, B-type natriuretic peptide, lactate, C-reactive protein, leukocytes, IL-6, NGAL, hepcidin-25) to predict postoperative severe fluid overload. Results: Urinary midkine, IL-6, NGAL and hepcidin-25 (all AUCs ≥0.79) predicted postoperative severe fluid overload (n = 5 patients). Urinary NGAL/hepcidin-25 ratio (AUC 0.867) predicted postoperative severe fluid overload after adjustment to EuroScore and need for norepinephrine on surgery day (odds ratio: 2.4). Conclusion: Urinary biomarkers on intensive care unit admission might be helpful to predict subsequent severe fluid overload after cardiac surgery.
Keywords: IL-6; NGAL/hepcidin ratio; biomarker; cardiac surgery; cardiopulmonary bypass; cardiorenal syndrome; fluid overload; heart; kidney; midkine.
Lay abstract Aim: To assess whether proteins in the urine or blood or clinical routine laboratory parameters can predict severe body fluid overload after cardiac surgery. Patients & methods: In a pilot study, we studied 100 adult patients after cardiac surgery. After surgery, we measured proteins in the urine (midkine, IL-6, neutrophil gelatinase-associated lipocalin [NGAL], hepcidin-25) and blood (creatinine, urea, B-type natriuretic peptide, lactate, C-reactive protein, leukocytes, IL-6, NGAL, hepcidin-25) to predict postoperative severe fluid overload. Results: Urinary midkine, IL-6, NGAL and hepcidin-25 predicted postoperative severe fluid overload (n = 5 patients). Urinary NGAL/hepcidin-25 ratio predicted postoperative severe fluid overload after adjustment to important covariates. Conclusion: Urinary biomarkers might be helpful to predict subsequent severe fluid overload after cardiac surgery.