Dynamics of Mitral Complex Geometry and Functional Mitral Regurgitation During Heart Failure Treatment

Background.Although mitral complex geometry alteration has been speculated as a major mechanism for the reduction in mitral regurgitation (MR) after heart failure treatment, it has been difficult to recognize the mechanistic changes of the mitral apparatus because of the complex morphology and anatomical position. We investigated the contributions of the dynamic changes in mitral valve geometry with papillary muscle (PM) alignment to the reduction of functional MR after intensive heart failure treatment.Methods.Two dimensional/three-dimensional (2D/3D) echocardiography was performed in 10 patients with decompensated heart failure and functional MR before and after intensive therapy. We used novel software to analyze the volumetric images recorded by real-time 3D echocardiography. Reconstructed 3D images showed both leaflets and annulus configuration in relation to PM position. We measured maximum tenting length (max-Tent-L); mean tenting length (mean-Tent-L) and tenting volume (Tent-V); distances from anterior annulus to anterolateral PM (A-tethering length) and posteromedial PM (P-tethering length); the distance between two PM (interpapillary distance); and the angle made by the anterolateral PM, anterior annulus, and posteromedial PM (interpapillary angle).Results.MR decreased after intensive treatment in all patients (p<0.0001). Leaflet tenting decreased significantly after therapy (max-Tent-L, 16.8±2.5 vs. 13.3±2.0mm, p<0.001; mean-Tent-L, 9.5±2.1 vs. 7.3±1.3mm, p<0.001; Tent-V, 10.3±2.8 vs. 6.2±1.6ml, p=0.0002). P-tethering length shortened (46.9±5.1 vs. 38.6±4.9mm, p<0.001). Interpapillary distance (25.8±5.6 vs. 17.2±4.0mm, p<0.001) and interpapillary angle (32.0±7.3 vs. 23.8±7.5 degree, p<0.001) decreased after treatment.Conclusions.Dynamic changes in PM position during heart failure treatment resulted in the reduction of mitral valve tenting, which improved functional MR.