Refining the prognostic impact of functional mitral regurgitation in chronic heart failure

Abstract Aims Significant efforts are currently undertaken to reduce functional mitral regurgitation (FMR) in patients with chronic heart failure in the hope to improve prognosis. We aimed to assess the prognostic impact of FMR in heart failure with reduced ejection fraction (HFrEF) under optimal medical therapy (OMT) and various conditions of HFrEF. We further intended to identify a heart failure phenotype, where FMR is most likely a driving force and not a mere bystander of the disease. Methods and results We prospectively included 576 consecutive HFrEF patients into our long-term observational study. Functional [i.e. New York Heart Association (NYHA) class], echocardiographic, invasive haemodynamic, and biochemical (i.e. NT-proBNP, MR-proANP, MR-proADM, CT-proET-1, copeptin) measurements were performed at baseline. During a median follow-up of 62 months (interquartile range 52–76), 47% of patients died. Severe FMR was a significant predictor of mortality [hazard ratio (HR) 1.76, 95% confidence interval (CI) 1.34–2.30; P