Association of Acute Kidney Injury with Outcomes in Patients Undergoing Transcatheter Mitral Valve Repair

Introduction: Although transcatheter mitral valve repair (TMVr) is a contrast-free procedure, prior single-center studies have demonstrated a high incidence of acute kidney injury (AKI) following TMVr. The main objective of this study was to examine risk factors for AKI, and its association with outcomes in patients undergoing TMVr. Methods: We queried the National Readmission Database to identify TMVr procedures performed between January 2014 and December 2017. Complex samples multivariable logistic and linear regression models were used to identify risk factors associated with AKI, as well as to determine the association between AKI and clinical outcomes (in-hospital mortality, index length of stay (LOS), 30-day all-cause readmissions, and 30-day heart failure [HF] readmissions). Results: Of 14,623 patients who underwent TMVr during the study period, 2,001 (13.6%) had a diagnosis of AKI. HF, chronic kidney disease, chronic liver disease, fluid/electrolyte disorder, weight loss, nonelective admission, cardiogenic shock, and bleeding/transfusion were independently associated with an increased risk of AKI. In patients undergoing TMVr, AKI was associated with an increased risk of in-hospital mortality (adjusted odds ratio [aOR], 4.94; 95% confidence interval [CI], 2.92-8.34), 30-day all-cause readmissions (aOR, 1.91; 95% CI, 1.49-2.46), 30-day HF readmissions (aOR, 2.30; 95% CI, 1.38-3.84), and longer index LOS (adjusted parameter estimate, 5.78; 95% CI, 5.26-6.41). Conclusion: AKI in the setting of TMVr is common and is associated with worse clinical outcomes. Further studies are needed to determine if optimizing renal function prior to TMVr may improve outcomes, as well as to understand the impact of TMVr itself on renal function.