Functional Mitral Regurgitation Outcome and Grading in Heart Failure With Reduced Ejection Fraction.

Abstract Objectives This study aims to define excess-mortality linked to functional mitral regurgitation (FMR) quantified in routine-practice. Background Appraisal of FMR in heart failure with reduced ejection fraction (HFrEF) is challenging because risks of excess mortality remain uncertain and guidelines diverge. Methods Cases of HFrEF (ejection-fraction Results In the FMR cohort (age: 70 ± 11 years, ejection fraction: 36 ± 10%, effective regurgitant orifice area [EROA]: 0.09 ± 0.13 cm2), EROA distribution was skewed towards low-values (≥0.40 cm2 in only 8% vs 38% for the DMR cohort; P  Conclusions In HFrEF, FMR is skewed towards smaller EROA. Nevertheless, when measured in routine practice, EROA is the strongest independent FMR determinant of survival after diagnosis. Excess mortality increases exponentially above the threshold of 0.10 cm2, with a much steeper slope than in DMR, for any EROA increment. An expanded EROA-based stratification, superior to existing grading schemes in determining survival, should allow guideline harmonization.