Prognostic comparison of atrial and ventricular functional mitral regurgitation

Abstract

Objective: Atrial functional mitral regurgitation (A-FMR) has been suggested as a new aetiology of functional MR (MR); however, its prognosis and prognostic predictors are not fully elucidated. Aim of this study was to investigate the prognosis and prognostic predictors of A-FMR in comparison with ventricular functional MR (V-FMR).

Methods: Three hundred and seventy-eight consecutive patients with moderate-to-severe or severe functional MR were studied. Functional MR was classified into V-FMR (N=288) and A-FMR (N=90) depending on the alterations of left ventricle (LV) or left atrium (LA) along with clinical context and diagnosis of ischaemic heart disease or cardiomyopathy.

Results: During a median follow-up of 4.1 (2.0-6.7) years, all-cause mortality, cardiovascular mortality and heart failure (HF) hospitalisation occurred in 98 (26%), 81 (21%) and 177 (47%) patients, respectively, and rates of these events and the composite end point of all-cause mortality and HF hospitalisation were consistently higher in V-FMR than A-FMR (unadjusted HR 1.762 (95% CI 1.250 to 2.438), p<0.001; adjusted HR 1.654 (95% CI 1.027 to 2.664), p=0.038, for the composite end point). Further analysis showed different prognostic predictors between V-FMR and A-FMR; while age and LA volume index were independent prognostic predictors of both V-FMR and A-FMR, systolic blood pressure and B-type natriuretic peptide were also those of V-FMR, and estimated glomerular filtration rate, LV end-systolic dimension and tricuspid regurgitation were also those of A-FMR.

Conclusions: The prognosis of V-FMR was significantly worse than that of A-FMR, and prognostic predictors were different between V-FMR and A-FMR. Our study suggests the importance of discriminating A-FMR and V-FMR, and that different treatment strategies may be considered for each aetiology.

Keywords: echocardiography; heart failure; mitral regurgitation.

Figure 1

Characteristics of atrial and ventricular functional mitral regurgitation and prognostic comparison. (A) Characteristics of atrial functional mitral regurgitation (MR) and ventricular functional MR. (B) Kaplan-Meier analysis for the composite end point of all-cause mortality and heart failure hospitalisation showed that ventricular functional MR had significantly higher event rates compared with atrial functional MR (p=0.001, log-rank). LV, left ventricle.

Figure 2

Kaplan-Meier analysis for all-cause mortality, cardiovascular mortality and heart failure hospitalisation Kaplan-Meier analysis showed that event rates of (A) all-cause mortality, (B) cardiovascular mortality and (C) heart failure hospitalisation were consistently higher in ventricular functional mitral regurgitation (MR) compared with atrial functional MR.

Figure 3

Kaplan-Meier analysis for composite end point stratified by atrial fibrillation. There were no significant differences between atrial functional mitral regurgitation (A-FMR) with and without atrial fibrillation (AF) (p=0.31), while ventricular FMR (V-FMR) with AF had a significantly worse outcome compared with V-FMR with no AF (p=0.011).