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Urine hepcidin has additive value in ruling out cardiopulmonary bypass-associated acute kidney injury - an observational cohort study. Crit Care. 2011 Aug 4;15(4):R186 Authors: Haase-Fielitz A, Mertens PR, Plass M, Kuppe H, Hetzer R, Westerman M, Ostland V, Prowle JR, Bellomo R, Haase M Abstract
ABSTRACT: Introduction Conventional markers of acute kidney injury (AKI) lack diagnostic accuracy and are expressed only late after cardiac surgery with cardiopulmonary bypass (CPB). Recently, interest has focused on hepcidin, a regulator of iron homeostasis, as a unique renal biomarker. Methods We studied 100 adult patients in the control arm of a randomized controlled trial (clinicaltrials.gov NCT00672334) that were identified to be at increased risk of AKI after cardiac surgery with CPB. AKI was defined according to the RIFLE classification. Samples of plasma and urine were obtained simultaneously I) before CPB II) 6 hours after the start of CPB and III) at 24 hours after CPB. Plasma and urine hepcidin 25-isoforms were quantified by competitive enzyme-linked immunoassay. Results At 6 and 24 hours after CPB, in AKI-free patients (N=91) urine hepcidin concentrations had largely increased and were 3 to 7 times higher compared to patients with subsequent AKI (N=9) in whom postoperative urine hepcidin remained at preoperative levels (P = 0.004, P = 0.002). Furthermore, higher urine hepcidin and, even more so, urine hepcidin adjusted to urine creatinine at 6 hours after CPB discriminated patients who did not develop AKI (AUC-ROC 0.80 [95% CI 0.71-0.87]; 0.88 [95% CI 0.78-0.97]) or did not need renal replacement therapy initiation (AUC 0.81 [95% CI 0.72-0.88]; 0.88 [95% CI 0.70-0.99]) from those who did. At 6 hours, urine hepcidin adjusted to urine creatinine was an independent predictor of ruling out AKI (P = 0.011). Plasma hepcidin did not predict no development of AKI. The study findings remained essentially unchanged after excluding patients with preoperative chronic kidney disease. Conclusions Our findings suggest that urine hepcidin is an early predictive biomarker of ruling out AKI after CPB thereby contributing to early patients risk stratification.
PMID: 21816077 [PubMed - as supplied by publisher] Read more |
