Predicting Acute Kidney Injury Following Mitral Valve Repair

Background: Acute kidney injury (AKI) after cardiac surgery is associated with short-term and long-term adverse outcomes. Novel biomarkers have been identified for the early detection of AKI; however, examining these in every patient who undergoes cardiac surgery is prohibitively expensive. Society of Thoracic Surgeons (STS) and Age, Creatinine, and Ejection Fraction (ACEF) scores have been proven to predict mortality in bypass surgery. The aim of this study was to determine whether these scores can be used to predict AKI after mitral valve repair. Materials and Methods: Between January 2010 and December 2013, 196 patients who underwent mitral valve repair were enrolled. The clinical characteristics, outcomes, and scores of prognostic models were collected. The primary outcome was postoperative AKI, defined using the Kidney Disease Improving Global Outcome 2012 clinical practice guidelines for AKI. Results: A total of 76 patients (38.7%) developed postoperative AKI. The STS renal failure (AUROC: 0.797, P < .001) and ACEF scores (AUROC: 0.758, P < .001) are both satisfactory tools for predicting all AKI. The STS renal failure score exhibited superior accuracy compared with the ACEF score in predicting AKI stage 2 and 3. The overall accuracy of both scores was similar for all AKI and AKI stage 2 and 3 when the cut-off points of the STS renal failure and ACEF scores were 2.2 and 1.1, respectively. Conclusion: In conclusion, the STS renal failure score can be used to accurately predict stage 2 and 3 AKI after mitral valve repair. The ACEF score is a simple tool with satisfactory power in screening patients at risk of all AKI stages. Additional studies can aim to determine the clinical implications of combining preoperative risk stratification and novel biomarkers.