Mitral annular geometry in normal and myxomatous mitral valves: Three-dimensional transesophageal echocardiographic quantification

Background and aim of the study: The mitral annulus (MA) has a complex dynamic geometry that is difficult to visualize in two dimensions; hence, novel real-time three-dimensional transesophageal echocardiography (RT-3D-TEE) provides insights into its dynamic nature. The study aim was to investigate changes in MA geometry in normal subjects and to explore differences in patients with myxomatous mitral valve disease (MMVD), using 3D quantitation with RT-3D-TEE. Methods: Thirty-five participants (18 with MMVD, 17 normal subjects as controls) were enrolled into the study. The following geometric measurements were obtained at end-systole (ES) and end-diastole (ED): surface area, circumference, perimeter, height, commissure-to-commissure (C-C) diameter, anterior-toposterior (A-P) diameter, and the ratio of A-P diameter to C-C diameter (circularization). To detect the effect of the severity of mitral regurgitation (MR) on MA dynamics, patients with MMVD were allocated to two subgroups with mild (n = 7) or moderate/severe (n = 11) MR. Results: Control subjects demonstrated a saddle-shaped, elliptical MA configuration with slightly larger ES parameters. The MA shape was changed during the cardiac cycle, being more circular at ES and flatter at ED (p <0.05). In MMVD patients, the MA retained a saddle shape but became dilated and circular with larger ED parameters compared to controls (p <0.05). The degree of MA geometric changes was more prominent in moderate/severe MR patients (p <0.001), while mild MR patients displayed MA geometry and dynamics similar to those of controls. Conclusion: The MA geometry is altered in MMVD patients, with the extent of changes being determined by the severity of the MR. RT-3D-TEE provides high-quality images that permit a precise quantitative analysis of the 3D geometry of the MA.