Untargeted Metabolomic Analysis of Acute Kidney Injury After Maze-Inclusive Cardiac Surgery.
Abstract
BACKGROUND: The maze procedure is considered as the standard surgical treatment for atrial fibrillation and might be an independent risk factor for postoperative acute kidney injury (AKI). This study aimed to investigate the metabolic alterations associated with AKI following maze-inclusive cardiac surgery using untargeted metabolomics. METHODS: We prospectively enrolled 50 patients who underwent the maze procedure with concomitant cardiac surgery. AKI was diagnosed as an absolute increase in serum creatinine level of ≥ 0.3 mg/dL from baseline within 48 hours, or a ≥ 50% increase in serum creatinine within 7 days after surgery. Plasma samples were collected in operation and 24 hours after surgery, and untargeted metabolomic analysis was performed. Differential metabolites were identified and subjected to pathway enrichment analysis. Clinical variables and related metabolites were analyzed to elucidate relationship with AKI. RESULTS: The concomitant surgeries were valve surgeries in 37 patients, followed by coronary artery (8 patients), and aorta (5 patients). Postoperative AKI occurred in 23 patients (46%). Metabolomic profiling revealed upregulation of tryptophan metabolism in AKI patients, with five candidate metabolites implicated. Among them, kynurenic acid exhibited the most significant metabolite associated with AKI, with an area under the receiver operating characteristic curve of 0.93. Multivariable logistic regression analysis identified kynurenic acid as independent possible predictors of AKI. CONCLUSION: Tryptophan metabolism is significantly upregulated in patients with AKI after maze-inclusive cardiac surgery. Kynurenic acid presumed in this study represents as candidate metabolite of postoperative AKI, providing an opportunity to gain insight into the underlying pathophysiology through further targeted metabolomics. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0011192.
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