The Evolving Concept of Secondary Mitral Regurgitation Phenotypes: Lessons From the M-TEER Trials

Meta-analysis of transcatheter edge-to-edge repair vs surgery for secondary mitral regurgitation

BACKGROUND

Transcatheter edge-to-edge repair (TEER) in patients with secondary mitral regurgitation (MR) has shown variable outcomes in clinical studies when compared with mitral valve surgery. We conducted a meta-analysis to reconcile the data.

METHODS

Online databases were searched for studies assessing TEER vs surgery for secondary MR. The outcomes of interest were length of hospital stay, all deaths, heart failure (HF) rehospitalization, mitral valve reintervention, implantation of left ventricular assist device (LVAD), stroke and recurrence of grade 3 or 4 MR. Pooled odds ratios (OR) and standardized mean difference (SMD), with 95 % confidence intervals (CI) were calculated.

RESULTS

Eight studies (1 randomized and 7 observational) with a total of 1436 patients (TEER n = 826, surgery n = 610) were included. Length of hospital stay was shorter in the TEER group (SMD -2.50, 95 % CI -4.65 to -0.35, p = 0.02). No significant differences were found between the two groups with respect to all deaths (p = 0.80), HF rehospitalization, mitral valve reintervention, implantation of LVAD and stroke. Recurrence of grade 3 or 4 MR was higher in the TEER group (OR 5.33, 95 % CI 2.57 to 11.03, p < 0.00001).

CONCLUSIONS

In patients with secondary MR, TEER and surgery have comparable outcomes such as mortality, except for the lower recurrence of grade 3 or 4 MR in the surgical group. Thus, TEER may be the first approach in such patients, except in low surgical risk cases who need other concomitant cardiac surgeries.

Disproportionate vs. Proportionate Secondary Mitral Regurgitation: A Long-Term Pilot Analysis After Mitral Valve Surgery

Objectives: The treatment of secondary mitral regurgitation (MR) is still controversial. In 2019, a new conceptual framework was introduced, distinguishing between patients with a degree of MR "proportionate" to the left ventricular (LV) dilatation and patients in whom the severity of MR is "disproportionate" to the LV dilatation. The aim of this study was to compare the long-term outcome of patients with disproportionate vs. proportionate secondary MR who underwent mitral valve (MV) surgery. Methods: From January 2012 to June 2022, 96 patients with a preoperative diagnosis of pure secondary MR and LV dysfunction underwent MV surgery. The patients were divided in two groups, disproportionate vs. proportionate MR, according to echocardiographic parameters. A 5.2 (3.5-7.5) years complete clinical and echocardiographic follow-up was performed. Results: In the study period, 61 patients with disproportionate and 35 patients with proportionate MR underwent surgical MV repair or MV replacement. The thirty-day outcome was comparable in the two groups. At long-term follow-up, mortality was 5% in the disproportionate group vs. 11% in the proportionate group (p = 0.2), and cardiovascular mortality was 3% vs. 9%, respectively (0.5). Rehospitalization for heart failure was 6% vs. 20% (p = 0.04), and the rate of patients with New York Heart Association (NYHA) functional class ≥ III was 8% vs. 26%, respectively (p = 0.01). LV volumes were significantly higher in the proportionate group, thus presenting a lower LV ejection fraction (p < 0.001 and p = 0.03, respectively). No cases of recurrent MR have been observed. Conclusions: In this first exploratory analysis, patients with disproportionate secondary MR seem to present a possible benefit in terms of mortality and cardiovascular mortality, although not ones reaching statistical significance. Nevertheless, significant advantages were observed in terms of rehospitalization for heart failure, clinical status and symptoms, LV volumes, and LV function. Among patients referred to cardiac surgery, identifying the subset of patients with functional MR, who may obtain more significant advantages from surgery, seems relevant for patient selection, risk stratification, and to predict long-term outcomes.

Transcatheter edge-to-edge repair for mitral regurgitation

Mitral valve transcatheter edge-to-edge repair (M-TEER) has emerged as a transformative therapy for mitral regurgitation (MR), addressing the unmet needs of patients unsuitable for surgery. Landmark trials such as EVEREST II, COAPT, and MITRA-FR have established the safety and efficacy of M-TEER, in both patients with primary (PMR) and secondary MR (SMR). Recent trials, including RESHAPE-HF2 and MATTERHORN, have expanded our understanding and refueled discussions regarding patient selection and appropriate treatment indications in SMR. These trials have also contributed to the discussion regarding SMR phenotypes most appropriate for M-TEER. This review summarizes the evidence from pivotal trials, discusses patient selection, device advancements, potential future directions, and outlines ongoing trials that may shape future clinical practice.

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.

Registries on transcatheter edge-to-edge repair in heart failure: Current evidence and future perspectives

AIMS

Secondary mitral regurgitation (SMR) and tricuspid regurgitation (TR) are the most common valvular heart diseases in patients with heart failure (HF). Transcatheter edge-to-edge repair (TEER) devices designed for treating MR and TR have been successfully tested in randomized controlled trials, but methodological issues have often challenged their interpretation. This manuscript aimed to provide an overview of TEER registries on SMR and TR in HF, highlighting their key features, describing clinical characteristics and outcomes of patients receiving these devices, and exploring the available data limitations.

METHODS AND RESULTS

PubMed, Web of Science, and EMBASE were searched for registries reporting on TEER in SMR or TR. Registries were excluded if single-centre and with <100 patients. Twenty-six registries (46% prospective, 12% ongoing), including a total cohort of 18 925 patients, were retrieved for TEER in SMR, and six registries (50% retrospective, 33% ongoing) reported on the use of TEER for TR in a total cohort of 1412 patients. Limited geographical representativity outside North America and Europe, high number of missing values, and inconsistency in data reporting were the main existing evidence limitations.

CONCLUSION

Registries on TEER represent a key data source in a setting where it is difficult to conduct randomized controlled trials. However, limitations in design, patient characterization, and outcomes reporting restrain their use. A novel conceptual framework for future prospective TEER registries, as proposed in this document, might inform current practice, address relevant clinical questions and future trial design.

Hospitalization of Symptomatic Patients With Heart Failure and Moderate to Severe Functional Mitral Regurgitation Treated With MitraClip: Insights From RESHAPE-HF2

BACKGROUND

For patients with functional mitral regurgitation (FMR) and symptomatic heart failure (HF), randomized trials of mitral transcatheter edge-to-edge repair (M-TEER) have produced conflicting results.

OBJECTIVES

This study sought to assess the impact of M-TEER on hospitalization rates, and explore the effects of M-TEER on patients who did or did not have a history of recent HF hospitalizations before undergoing M-TEER.

METHODS

RESHAPE-HF2 (Randomized Investigation of the MitraClip Device in Heart Failure: 2nd Trial in Patients with Clinically Significant Functional Mitral Regurgitation) included patients with symptomatic HF and moderate to severe FMR (mean effective regurgitant orifice area 0.25 cm2; 14% >0.40 cm2, 23% <0.20 cm2) and showed that M-TEER reduced recurrent HF hospitalizations with and without the addition of cardiovascular (CV) death and improved quality of life. We now report the results of prespecified analyses on hospitalization rates and for the subgroup of patients (n = 333) with a HF hospitalization in the 12 months before randomization.

RESULTS

At 24 months, the time to first event of CV death or HF hospitalization (HR: 0.65; 95% CI: 0.49-0.85; P = 0.002), the rate of recurrent CV hospitalizations (rate ratio [RR]: 0.75; 95% CI: 0.57-0.99; P = 0.046), the composite rate of recurrent CV hospitalizations and all-cause mortality (RR: 0.74; 95% CI: 0.57-0.95; P = 0.017), and of recurrent CV death and CV hospitalizations (RR: 0.76; 95% CI: 0.58-0.99; P = 0.040), were all lower in the M-TEER group. The RR of recurrent hospitalizations for any cause was 0.82 (95% CI: 0.63-1.07; P = 0.15) for patients in the M-TEER group vs control group patients. Patients randomized to M-TEER lost fewer days due to death or HF hospitalization (13.9% [95% CI: 13.0%-14.8%] vs 17.4% [95% CI: 16.4%-18.4%] of follow-up time; P < 0.0001, and 1,067 vs 1,776 total days lost; P < 0.0001). Patients randomized to M-TEER also had better NYHA functional class at 30 days and at 6, 12, and 24 months of follow-up (P < 0.0001). A history of HF hospitalizations before randomization was associated with worse outcomes and greater benefit with M-TEER on the rate of the composite of recurrent HF hospitalizations and CV death (Pinteraction = 0.03) and of recurrent HF hospitalizations within 24 months (Pinteraction = 0.06).

CONCLUSIONS

These results indicate that a broader application of M-TEER in addition to optimal guideline-directed medical therapy should be considered among patients with symptomatic HF and moderate to severe FMR, particularly in those with a history of a recent hospitalization for HF.

Transcatheter Valve Repair in Heart Failure with Moderate to Severe Mitral Regurgitation

BACKGROUND

Whether transcatheter mitral-valve repair improves outcomes in patients with heart failure and functional mitral regurgitation is uncertain.

METHODS

We conducted a randomized, controlled trial involving patients with heart failure and moderate to severe functional mitral regurgitation from 30 sites in nine countries. The patients were assigned in a 1:1 ratio to either transcatheter mitral-valve repair and guideline-recommended medical therapy (device group) or medical therapy alone (control group). The three primary end points were the rate of the composite of first or recurrent hospitalization for heart failure or cardiovascular death during 24 months; the rate of first or recurrent hospitalization for heart failure during 24 months; and the change from baseline to 12 months in the score on the Kansas City Cardiomyopathy Questionnaire-Overall Summary (KCCQ-OS; scores range from 0 to 100, with higher scores indicating better health status).

RESULTS

A total of 505 patients underwent randomization: 250 were assigned to the device group and 255 to the control group. At 24 months, the rate of first or recurrent hospitalization for heart failure or cardiovascular death was 37.0 events per 100 patient-years in the device group and 58.9 events per 100 patient-years in the control group (rate ratio, 0.64; 95% confidence interval [CI], 0.48 to 0.85; P = 0.002). The rate of first or recurrent hospitalization for heart failure was 26.9 events per 100 patient-years in the device group and 46.6 events per 100 patient-years in the control group (rate ratio, 0.59; 95% CI, 0.42 to 0.82; P = 0.002). The KCCQ-OS score increased by a mean (±SD) of 21.6±26.9 points in the device group and 8.0±24.5 points in the control group (mean difference, 10.9 points; 95% CI, 6.8 to 15.0; P<0.001). Device-specific safety events occurred in 4 patients (1.6%).

CONCLUSIONS

Among patients with heart failure with moderate to severe functional mitral regurgitation who received medical therapy, the addition of transcatheter mitral-valve repair led to a lower rate of first or recurrent hospitalization for heart failure or cardiovascular death and a lower rate of first or recurrent hospitalization for heart failure at 24 months and better health status at 12 months than medical therapy alone. (Funded by Abbott Laboratories; RESHAPE-HF2 ClinicalTrials.gov number, NCT02444338.).

Long-Term Outcomes After Edge-to-Edge Repair of Secondary Mitral Regurgitation: 5-Year Results From the EuroSMR Registry

BACKGROUND

Mitral valve transcatheter edge-to-edge repair (M-TEER) reduces secondary mitral regurgitation (MR) in heart failure and impacts survival in selected patients as demonstrated in the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trial. However, long-term outcome data after M-TEER under real-world conditions are lacking.

OBJECTIVES

This study sought to assess long-term efficacy and survival after M-TEER in a large real-world registry.

METHODS

We analyzed patients with significant secondary MR undergoing M-TEER from the EuroSMR (European Registry of Transcatheter Repair for Secondary Mitral Regurgitation) registry. Long-term MR reduction, functional outcomes, survival rate, and predictors for all-cause mortality were assessed.

RESULTS

In this study, 1,628 patients undergoing M-TEER (mean age 73.8 years, mean EuroSCORE II [European System for Cardiac Operative Risk Evaluation II] 6.9%, 86.6% NYHA functional class ≥III) with available long-term data were included. Five-year survival was 35.0%. Long-term MR reduction (MR grade ≤2+: baseline 4.1%, discharge 92.2%, 5-year follow-up 85.5%; P < 0.001) and functional improvement (NYHA ≤II: baseline 13.4%, 5-year follow-up 60.1%; P < 0.001) was observed. The degree of residual MR was associated with 5-year survival (residual MR grade ≤1+: 38.6%; 2+: 30.5%; ≥3+: 22.6%; P < 0.001). Independent predictors for 5-year all-cause mortality post-M-TEER included age, renal function, residual MR, NYHA functional class, left ventricular ejection-fraction, and COAPT trial eligibility (P < 0.01 for all).

CONCLUSIONS

This extensive multicenter registry underscores the long-term efficacy of M-TEER in real-world clinical practice and identifies predictors for long-term survival. These findings contribute valuable insights for optimizing patient selection in routine clinical interventions.

Mitral Transcatheter Edge-to-Edge Repair and Clinical Value of Novel Echocardiographic Biomarkers: A Hypothesis-Generating Study

BACKGROUND

Longitudinal data on reverse cardiac remodeling and outcomes after transcatheter edge-to-edge repair (TEER) are limited.

METHODS

A total of 78 patients with severe mitral regurgitation (MR) were included retrospectively. All patients had echocardiography at baseline and again six months after TEER. They were monitored for a primary composite endpoint, consisting of heart failure hospitalization and cardiovascular death, over 13 months.

RESULTS

Significant decreases in the left ventricular ejection fraction (LVEF), all myocardial work indices (except global wasted work), and the left atrial reservoir were observed after TEER. Additionally, there was a decrease in the pulmonary artery systolic pressure and an increase in the tricuspid annular plane systolic excursion/pulmonary artery systolic pressure (TAPSE/PASP) ratio. A post-TEER TAPSE/PASP ratio of <0.47 (HR: 4.76, p-value = 0.039), and a post-TEER left atrial reservoir of <9.0% (HR: 2.77, p-value = 0.047) were associated with the primary endpoint.

CONCLUSIONS

Echocardiography post-TEER reflects impairment in ventricular performance due to preload reduction and right ventricle and pulmonary artery coupling improvement. Short-term echocardiography after TEER identifies high-risk patients who could benefit from a close clinical follow-up. The prognostic significance of LA strain and the TAPSE/PASP ratio should be validated in subsequent large-scale prospective studies.