MITRAL VALVE GEOMETRY IN HYPERTROPHIC CARDIOMYOPATHY AND ITS ROLE IN THE DEVELOPMENT OF LEFT VENTRICULAR OUTFLOW TRACT OBSTRUCTION

Aim. To evaluate structural features of the mitral valve (MV) in patients with left ventricular hypertrophy (LVH) and to identify characteristics of MV structural remodeling in hypertrophic obstructive cardiomyopathy (HOCM) patients using three-dimensional MV quantification analysis.Material and Methods. The study included 48 patients with HOCM and 15 patients with arterial hypertension and LVH. All patients underwent standard echocardiography and real-time 3D transesophageal echocardiography, followed by MV reconstruction with quantitative analysis. Quantitative analysis of MV included assessment of the mitral annulus and cusps.Results. Differences in characteristics of three-dimensional MV model between patients with HOCM and arterial hypertension and LVH were identified. In patients with HOCM, the height of the fibrous ring of the MV was increased compared to that in patients with arterial hypertension (8.00±1.72 mm vs. 5.99±1.95 mm; p=0.02). Mitral annular height (r=-0.55; p=0.02) and area(3D) (r=-0.30; p=0.04) correlated with peak LV outflow tract (LVOT) gradient. MV nonplanarity index was higher in HOCM patients (2.37±0.47 units vs. 1.73±0.62 units; p=0.02). Mitral annular maximal velocity correlated with peak (r=0.48, p=0.002) and mean (r=0.47, p=0.01) LVOT gradients. Anterior (6.40±2.04 sm2 vs. 5.07±1.04 sm2 ; p<0.05) and posterior (6.61±2.01 см2 vs. 5.27±1.23 см2 ; p=0.006) cusp areas, total cusp area (13.01±3.54 sm2 vs. 10.34±1.82 sm2 ; p=0.008), and total cusp area to annular area ratio (1.31±0.2 units vs. 1.15±0.09 units; р=0.01) had higher values in patients with HOCM. Correlation existed between anterior leaflet length and peak LVOT gradient (r=-0.45; p=0.01). Patients with HOCM had increased anterior leaflet angle compared to patients with arterial hypertension and LVH (32.13±9.21° vs. 24.86±4.45°; р=0.04).Conclusion. Compared to patients with arterial hypertension and LVH, patients with HOCM experienced more pronounced MV annular remodeling presented as an increase in the annular height, which was accompanied by an increase in the cusp areas and the anterior leaflet angle. In patients with HOCM, the annular area and the maximum mitral annular velocity correlated with LVOT gradient.