Transcatheter edge-to-edge repair (TEER) is an effective intervention for high-risk patients with severe symptomatic mitral regurgitation (MR), but its acute impact on left ventricular (LV) function has not been well studied using advanced echocardiographic techniques. This study investigated the immediate effects of TEER on LV volumes and functions, as well as their influence on mid-term outcomes, using high-resolution 3D transesophageal echocardiography. In 80 patients undergoing TEER for severe MR (mean age 79±8 years, 49% with primary MR), LV end-diastolic volume (LVEDV) and stroke volume significantly decreased (161±61 to 147±54 ml and 69±18 to 50±15 ml, respectively), while end-systolic volume increased (92±60 to 97±45 ml; p<0.0001 for all). Left ventricular ejection fraction (LVEF; 48±16% to 38±14%), global longitudinal strain (GLS; 16.2±6.8% to 12.8±5.4%), and global circumferential strain (GCS; 25±10.5% to 18.7±8.5%) deteriorated significantly (p<0.0001 for all). Absolute reductions in LVEF and GCS were associated with baseline values and afterload reduction, indicated by 3D vena contracta area decline (r=0.47 and r=0.65; p<0.0001), while GLS reduction was linked to baseline values and inversely proportional to LVEDV (r=0.63; p<0.0001). Relative LVEF reduction emerged as the strongest predictor of mortality, with a hazard ratio of 1.76 (1.12-2.76) per 10% decrease. In conclusion, the acute decline in LV function following TEER correlates with the degree of MR reduction, with greater impacts observed in circumferential function and patients with higher baseline LVEF. Relative LVEF reduction is a critical echocardiographic predictor of mortality.
