Evaluating Mitral TEER in the Management of Moderate Secondary Mitral Regurgitation Among Heart Failure Patients

BACKGROUND Moderate secondary mitral regurgitation (SMR) represents a subgroup of heart failure (HF) patients with treatment restricted to medical therapy. Outcomes in patients with moderate SMR treated with mitral transcatheter edge-to-edge repair (M-TEER) are less well known. OBJECTIVES The aim of this study was to assess the safety and effectiveness of M-TEER in subjects with moderate SMR using the EXPANDed studies. METHODS One-year outcomes in subjects from the EXPANDed studies (EXPAND [A Contemporary, Prospective Study Evaluating Real-world Experience of Performance and Safety for the Next Generation of MitraClip Devices] and EXPAND G4 [A Post-Market Study Assessment of the Safety and Performance of the MitraClip G4 System] MitraClip studies) with baseline moderate SMR (2+), per echocardiographic core laboratory (ECL) assessment, were compared with subjects with baseline severe SMR (>= 3+). RESULTS There were 335 subjects with moderate SMR and 525 with severe SMR at baseline per ECL review. Baseline characteristics were similar between the 2 subgroups. After treatment with M-TEER, significant MR reduction was achieved in both groups. Significant left ventricular (LV) reverse remodeling was observed through 1 year, with a >20 mL decrease in LV end-diastolic and end-systolic volumes on average in the moderate SMR group. Significant 1-year improvements in NYHA functional class (>78% NYHA functional class I or II) and quality of life (>20 points on the Kansas City Cardiomyopathy Questionnaire-Overall Summary) were observed in subjects with moderate SMR. Similarly, low rates of major adverse events, all-cause mortality, and HF hospitalizations were observed between the 2 subgroups through 1 year. CONCLUSIONS In the EXPANDed studies, subjects with moderate SMR treated with M-TEER had improvements similar to subjects with severe SMR in quality of life and positive LV remodeling at 1 year. Future studies are needed to evaluate if M-TEER would be beneficial for HF patients with moderate SMR. (JACC Heart Fail. 2025;13:213-225) (c) 2025 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).