Aims: Right ventricular dysfunction (RVD), as expressed by right ventricular to pulmonary artery coupling, has recently been identified as a strong outcome predictor in patients undergoing mitral valve edge‐to‐edge repair (M‐TEER) for secondary mitral regurgitation (MR). The aim of this study was to define RVD in patients undergoing M‐TEER for primary MR (PMR) and to evaluate its impact on procedural MR reduction, symptomatic development and 2‐year all‐cause mortality. Methods and results: This multicentre study included patients undergoing M‐TEER for symptomatic PMR at nine international centres. The study cohort was divided into a derivation (DC) and validation cohort (VC) for calculation and validation of the best discriminatory value for RVD. A total of 648 PMR patients were included in the study. DC and VC were comparable regarding procedural success and outcomes at follow‐up. Sensitivity analysis identified RVD as an independent predictor for 2‐year mortality in the DC (hazard ratio [HR] 2.37, 95% confidence interval [CI] 1.47–3.81, p < 0.001), which was confirmed in the VC (HR 2.06, 95% CI 1.36–3.13, p < 0.001). Procedural success (MR ≤2+) and symptomatic improvement at follow‐up (New York Heart Association [NYHA] class ≤II) were lower in PMR patients with RVD (MR ≤2+: 82% vs. 93%, p = 0.002; NYHA class ≤II: 57.3% vs. 66.5%, p = 0.09 for with vs. without RVD). In all PMR patients, the presence of RVD significantly impaired 2‐year survival after M‐TEER (HR 2.23, 95% CI 1.63–3.05, p < 0.001). Conclusions: Mitral valve edge‐to‐edge repair is an effective treatment option for PMR patients. The presence of RVD is associated with less MR reduction, less symptomatic improvement and increased 2‐year mortality. Accordingly, RVD might be included into pre‐procedural prognostic considerations.

Conflicting results from 2 randomized clinical trials of transcatheter mitral valve edge-to-edge repair in secondary mitral regurgitation (SMR) have led to the recognition that SMR is a heterogeneous disease entity presenting with different functional and morphological phenotypes. This review summarizes the current knowledge on SMR caused primarily by atrial secondary mitral regurgitation (aSMR) and ventricular SMR pathology. Although aSMR is generally characterized by severe left atrial enlargement in the setting of preserved left ventricular anatomy and function, different patterns of mitral annular distortion cause different phenotypes of aSMR. In ventricular SMR, the relation of SMR severity to left ventricular dilation as well as the degree of pulmonary hypertension and right ventricular dysfunction are important phenotypic characteristics, which are key for a better understanding of prognosis and treatment response.

Transcatheter tricuspid valve edge-to-edge repair (T-TEER) has been reported to be associated with right ventricular reverse remodeling (RVRR). Data on the temporal evolution of this phenomenon are scarce. The aim of this study was to evaluate RVRR over the course of 2-year follow-up after T-TEER using sequential 3-dimensional echocardiograms (3DE). The study included T-TEER patients with available 3DE at baseline and discharge. Further follow-ups were scheduled at 1 month, 6 months, as well as 1 and 2 years. The 3DE evaluation included right ventricular volumes (right ventricular end-diastolic volume [RVEDV^3D]; right ventricular end-systolic volume [RVESV^3D]), right ventricular ejection fraction (RVEF^3D), and RV longitudinal strain of the free wall and the septum. The study included 231 patients (median age 82 [IQR: 79-86] years, 48% women). We observed a biphasic pattern of RVRR following T-TEER consisting of early RV volume unloading (phase 1, reduced RVEDV^3D) and later structural remodeling (phase 2, reduced RVESV^3D). Whereas RVEDV^3D was significantly reduced early after the procedure (-9.7% from baseline to discharge; P < 0.001), RVESV^3D remained unchanged at 1-month follow-up. Reduction in RVESV^3D was observed at 6-month follow-up for the first time (-5.4% from baseline to 6-month follow-up; P < 0.001). Reduction in both RVEDV^3D and RVESV^3D peaked at 1-year follow-up and remained stable until 2 years after T-TEER. RV function declined early after T-TEER and gradually increased over the course of follow-up (RVEF^3D at baseline 42.2% ± 8.9%, discharge 31.1% ± 9.4%, 2-year follow-up 41.6% ± 8.9%). The 3D RV longitudinal strain of the septum and 3D RV longitudinal strain of the free wall developed analogously. RVRR following T-TEER occurs in 2 stages and involves early RV unloading (reduction in RVEDV^3D) and later structural RVRR (reduction in RVESV^3D) with an improvement in RVEF.