title: Identification of Plasma Metabolites Prognostic of Acute Kidney Injury after Cardiac Surgery with Cardiopulmonary Bypass.
abstract: Acute kidney injury (AKI) is a frequent complication after cardiopulmonary bypass, but early detection of postoperative AKI remains challenging. Protein biomarkers predict AKI excellently in homogeneous cohorts but are less reliable in patients suffering from various comorbidities. We employed nuclear magnetic resonance spectroscopy in a prospective study of 85 adult cardiac surgery patients to identify metabolites prognostic of AKI in plasma specimens collected 24 h after surgery. Postoperative AKI of stages 1-3, as defined by the Acute Kidney Injury Network (AKIN), developed in 33 cases. A random forests classifier trained on the NMR spectra prognosticated AKI across all stages, with an average accuracy of 80 ± 0.9% and an area under the receiver operating characteristic curve of 0.87 ± 0.01. Prognostications were based, on average, on 24 ± 2.8 spectral features. Among the set of discriminative ions and molecules identified were Mg(2+), lactate, and the glucuronide conjugate of propofol. Using creatinine, Mg(2+), and lactate levels to derive an AKIN index score, we found AKIN 1 disease to be largely indistinguishable from AKIN 0, in concordance with the rather mild nature of AKIN 1 disease.
authors.affiliation: †Institute of Functional Genomics, University of Regensburg, Josef-Engert-Str. 9, 93053 Regensburg, Germany.
authors.forename: Helena U
authors.initials: HU
authors.lastname: Zacharias
authors.affiliation: †Institute of Functional Genomics, University of Regensburg, Josef-Engert-Str. 9, 93053 Regensburg, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Hochrein
authors.affiliation: †Institute of Functional Genomics, University of Regensburg, Josef-Engert-Str. 9, 93053 Regensburg, Germany.
authors.forename: Franziska C
authors.initials: FC
authors.lastname: Vogl
authors.affiliation: ‡Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nürnberg, Ulmenweg 18, 91054 Erlangen, Germany.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Schley
authors.affiliation: §Department of Anaesthesiology, Friedrich-Alexander-University Erlangen-Nürnberg, Krankenhausstr. 12, 91054 Erlangen, Germany.
authors.forename: Friederike
authors.initials: F
authors.lastname: Mayer
authors.affiliation: §Department of Anaesthesiology, Friedrich-Alexander-University Erlangen-Nürnberg, Krankenhausstr. 12, 91054 Erlangen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Jeleazcov
authors.affiliation: ‡Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nürnberg, Ulmenweg 18, 91054 Erlangen, Germany.
authors.forename: Kai-Uwe
authors.initials: KU
authors.lastname: Eckardt
authors.affiliation: ‡Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nürnberg, Ulmenweg 18, 91054 Erlangen, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Willam
authors.affiliation: †Institute of Functional Genomics, University of Regensburg, Josef-Engert-Str. 9, 93053 Regensburg, Germany.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Oefner
authors.affiliation: †Institute of Functional Genomics, University of Regensburg, Josef-Engert-Str. 9, 93053 Regensburg, Germany.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Gronwald
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000209:etiology; D015415:Biomarkers / Q000097:blood*; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D006801:Humans; D013058:Mass Spectrometry; D019906:Nuclear Magnetic Resonance, Biomolecular; D011379:Prognosis; D012372:ROC Curve
chemical_list: D015415:Biomarkers
keywords: AKI; NMR spectroscopy; acute kidney injury; metabolomics; molecular signature; prognostication