Backgrounds:
Recent studies evidenced growth of the mitral leaflet (ML) in patients with functional mitral regurgitation (FMR), casting doubt on the traditional understanding of FMR. The aim of this study was to explore whether growth of ML occurs in patients with non-ischemic left ventricular (LV) systolic dysfunction and to examine whether there was any relationship between the growth of ML and the development of FMR.
Methods:
Echocardiographic examination was performed in 3 groups of patients: patients with non-ischemic LV systolic dysfunction [LV ejection fraction (EF) <50%] and significant FMR (MR jet area ratio≥20%) (group1, n=40), patients with non-ischemic LV systolic dysfunction but no significant FMR (MR jet area ratio <20%) (group2, n=30), and normal subjects (group3, n=40). The lengths of the anterior (AML) and posterior (PML) mitral leaflets as well as the anterior-posterior mitral annular dimension (MAD) were measured to reflect the degree of ML growth and mitral annular dilation. The ratio of AML and PML to MAD (AML: MAD, PML: MAD) were calculated respectively to assess the adequacy of ML growth in the context of mitral annular dilation.
Results:
The AML, PML, and the MAD were all increased in patients with LV systolic dysfunction (group1 and group2) compared with normal subjects (group3). In patients with LV systolic dysfunction, both PML and MAD were further increased in group1 compared with group2. However, AML showed no significant difference between the 2 groups. As a result, PML:MAD showed no significant difference between group1 and group2, while AML:MAD was significantly decreased in group1 compared with group2 (Table 1).
Conclusion:
Mitral leaflet growth occurs in patients with non-ischemic LV systolic dysfunction. Insufficient growth of the anterior mitral leaflet relative to dilated mitral annulus is associated with the development of significant FMR.
Functional mitral regurgitation and papillary muscle dyssynchrony in patients with left ventricular systolic dysfunction