Effects of combined myectomy with mitral valve repair on a three-dimensional mitral valve model and left ventricle outflow obstruction in patients with hypertrophic cardiomyopathy

Aim . To assess the effects of combined myectomy with mitral valve repair on a three-dimensional model of the mitral valve in patients with obstructive hypertrophic cardiomyopathy. Methods. 24 patients with obstructive hypertrophic cardiomyopathy and left ventricular outflow obstruction over 50 mm Hg at rest were recruited in a study. Eight patients underwent combined myectomy with mitral valve repair according to the Carpentier method. Seven patients underwent the Alfieri's edge-to-edge repair, and nine patients underwent secondary chordae resection using the Ferrazzi’s technique. Before combined myectomy and two weeks after it, all patients underwent standard transthoracic echocardiography and real-time 3D transesophageal imaging of the mitral valve, followed by quantitative 3D reconstruction of the mitral valve and calculation of the annulus, the leaflets, and the aorto-mitral angle. Results. Despite the selected mitral valve repair technique, we observed a decrease in the LVOT obstruction gradient. There were no differences in the residual obstruction gradient between the selected mitral valve repair technique. Patients with obstructive hypertrophic cardiomyopathy, who underwent combined myectomy and posterior mitral leaflet plasty valve according to the Carpentier approach, reported a correlation of a decrease in the LVOT obstruction with the non-planar angle (r = -0.83; p = 0.040), sphericity index (r = 0.83; p = 0.04) and a decrease in the velocity excursion of the annulus (r = 0.94; p = 0.005). Patients who underwent the Alfieri's edge-to-edge repair demonstrated that the residual LVOT obstruction gradient depended on the annulus height (r = 0.90; p = 0.04) and the ratio of this height to the commissural diameter of the annulus ( r = 0.90; p = 0.04). After secondary chordae resection, a decrease in the LVOT obstruction gradient correlated with the sphericity index (r = 0.77; p = 0.03), the anterolateral-posteromedial annulus diameter (r = -0.72; p = 0.04), the anterior (r = -0.78; p = 0.02) and posterior (r = -0.78; p = 0.02) leaflets, the ratio of the total leaflet length to the anteroposterior diameter of the annulus (r = -0.83; p = 0.01), the area (r = -0.76; p = 0.0з) and the mitral valve tenting height (r = -0.95; p = 0.00). Conclusion .Combined myectomy with mitral valve repair is the method of choice in the treatment of patients with obstructive hypertrophic cardiomyopathy. The comparison of three mitral valve repair techniques did not reveal any differences in the residual LVOT obstruction gradient. However, the Alfieri's edge-to-edge repair may be considered as the most physiological technique to repair dynamic LVOT obstruction.