Mitral annular dynamics after transcatheter edge-to-edge repair for functional mitral regurgitation: comparison with surgical annuloplasty

Abstract Background Transcatheter edge-to-edge repair (TEER) is a recently emerged therapeutic option for functional mitral regurgitation (FMR). Although the mitral annular shape and function may play an important role in the pathophysiology of FMR, few reports have evaluated the impact of TEER. We sought to investigate the impact of TEER on the mitral annulus and its motion in FMR compared with that of mitral annuloplasty (MAP). Methods Using three-dimensional transesophageal echocardiography, we evaluated the mitral annular morphology and dynamic motion in patients who underwent TEER or MAP before and after the procedures. Mitral annulus analysis was performed by a semi-automatic program to create a dynamic model of the three-dimensional structure, where the end-systolic annular structure was semi-automatically annotated and manually corrected, followed by automatic tracking of the annulus throughout the cardiac cycle . The mitral annular parameters such as mitral annular diameters, area, circumference, and height at all frames were automatically calculated from the model. In order to align the cardiac phase in each patient (i.e. to set the start and the end of diastole and systole at the same time for all patient), data were spline-interpolated to 100 systolic and 200 diastolic frames and then statistically analyzed. The dynamic changes of the parameters during the cardiac cycle were calculated as (maximum – minimum value) / maximum value after the interpolation. Results Patients who underwent TEER (n=20, 69±15 years, 40% female) and those who underwent MAP (n=16, 64±11 years, 6% female) had similar echocardiographic characteristics before the procedures. The maximum anteroposterior diameter and annulus area decreased after both TEER and MAP, while the intercommissural diameter decreased only after MAP but not after TEER. After TEER, the dynamic change in anteroposterior diameter throughout the cardiac cycle tended to decrease (p=0.055), while intercommissural change rather increased (p=0.049), resulting in preserved change in annulus area (p=0.74). After MAP, changes in both diameters and area decreased significantly (all p<0.05). MAP was associated with postoperative mitral annulus area immobility after adjustment (p=0.030). Conclusions The dynamic motion of the mitral annulus in patients with FMR was better preserved after TEER than after MAP. There was a decreasing trend in anteroposterior motion, which was compensated for by intercommissural motion after TEER. Future studies are needed to determine the association of these results with cardiac function and prognosis.