The role of left ventricular remodeling in functional mitral regurgitation: functional and prognostic implications in patients with heart failure

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Abstract Background Left ventricular (LV) dilatation plays a key role on functional mitral regurgitation (MR) in patients with heart failure (HF) and exercise MR causes an additional LV remodeling. This study sought to investigate the different phenotypes and prognostic impact of LV end-diastolic volume (EDV) and MR during exercise in HF patients of any left ventricular ejection fraction (LVEF) categorization. Methods 201 HF patients with reduced (n=119), mildly-reduced (n=46), and preserved (n=36) EF underwent exercise with gas exchange analysis combined with echocardiography for assessment of MR and were divided by 3 groups according to EDV index tertiles (T1 <70.1, T2 70.1–95.6, T3 >95.6 ml/m2). Results There was no significant difference in age (67±12 years) and peak oxygen consumption (VO2: 13.1±3.7 ml/kg/min) among the 3 groups but VE/VCO2 slope was higher in T3 group (T1 31±7, T2 31±5, T3 37±11, P<0.05). EDV index was positively correlated with VE/VCO2 slope (R=0.33, P<0.001) and effective regurgitant orifice area (EROA) of MR at rest (R=0.27, P=0.01) and exercise (R=0.45, P<0.001). During follow up, 48 patients had the composite end point of all cause death or HF hospitalization. The age and gender adjusted hazard ratio for the events in patients with MR >2+ was 1.8 (P=0.049) at rest and 1.9 (P=0.026) at exercise. The age, gender, peak VO2, VE/VCO2 slope, and exercise MR >2+ adjusted hazard ratio of EDV index 10 ml/m2 increase was 1.1 (P=0.041) and the ratio in patients with EDV index >95.6 ml/m2, derived by ROC curve (AUC=0.69, P<0.05), was 2.0 (P<0.033, figure). Conclusions Functional MR with LV dilation combines with the worse exercise gas exchange phenotype. Given also the predictive role of a EDV index cutoff of 95.6 ml/m2 attention for chamber geometry during exercise might become an indicator of mitral valve reparation. Funding Acknowledgement Type of funding sources: None.