Mitral annulus functional changes in different phenotypes of degenerative mitral regurgitation

Abstract Background The mitral annulus (MA) is a fibrous structure with anteroposterior contraction and increased annular height accentuating the annular saddle shape during systole. MA dynamics are abnormal in patients with mitral regurgitation (MR) and change according to the underlying etiology. Annular contractility damage is associated with the loss of physiologic morphology. Four-dimensional transesophageal echocardiography (RT4D-TEE) is an appropriate imaging technique for the quantification of these functional changes. Purpose The study aimed to evaluate echocardiographic MA functional features according to MR etiology. Methods The study included 191 patients with MR, 97 patients with functional (FMR), 94 with degenerative mitral regurgitation (DMR), and 40 subjects with normal mitral valve (MV). All patients diagnosed with MR by transthoracic echocardiography (TTE) underwent a comprehensive real-time four-dimensional transesophageal echocardiography (RT4D-TEE) evaluation of the MV apparatus. The images were acquired by a commercial ultrasound system. The analysis was performed offline by EchoPAC version 204 with a Four-Dimensional Automated Mitral Valve Quantification (4D Auto MVQ) software. The study measured mitral annular excursion (MAE), mitral annular max velocity (MAV), and annular area (2D) fraction (AAF). Results 1. Degenerative group was divided into Barlow disease – 29 (30.85%) patients, prolapse of one or two leaflet segments - 33 (35,10%) patients, and flail -34 (36.17%) patients. 2. Patients with FMR presented reduced values of MA functional parameters compared with patients with normal MV: MAE 4.07 mm/s (SD 1.96), p < 0.0001, MAV 27 mm/s (SD 9.62), p = 0.0001, AAF -0.29% (SD 1.4), p = 0.0003. 3. Subjects with DMR had increased values of mitral MA functional parameters compared with those with normal MV: MAE 5.94 mm/s (SD 2.48), p = 0.3494, MAV 39.07mm/s (SD 13.54), p = 0.0580, AAF -0.15% (SD 1.91), p = 0.0010. 4. In the DMR group, MA function was increased as follows: in case of MV prolapse: MAE 4.76 mm/s (SD 2.12), MAE 31.1mm/s (SD 6), AAF -0,1% (SD 1.53); in Barlow disease: MAE 4.96mm/s (1.74), MAE 35.04 mm/s (SD 9.85), AAF -0.11% (SD 1.22),, in patients with flail MAE 7.8 mm/s (SD 2.21), MAV 50.02 mm/s (SD 14.32), AAF -0.24% (SD 2.62). Conclusions 1. The MA function is damaged in FMR and DMR compared with normal MV. 2. MA velocities are increased in Barlow disease and patients with flail compared to patients with MV prolapse. 3. The subjects with MV flail presented the highest MA velocities.RT4D-TEE in FMR RT4D-TEE in DMR