TMVR: a 23% reduction in mortality for mitral regurgitation

Management of mitral regurgitation: a meta-analysis of percutaneous strategies

The management of mitral regurgitation (MR) remains a major therapeutic challenge, characterized by high morbidity and mortality and limited recourse to conventional surgery in high-risk surgical patients. Although several transcatheter mitral valve repair (TMVR) strategies—including transcatheter edge-to-edge repair (TEER) and percutaneous annuloplasty—are now available, evidence comparing their real-world efficacy to surgery or optimal medical therapy (OMT) remains heterogeneous. The distinction between degenerative MR (DMR) and functional MR (FMR) further complicates the interpretation of clinical results.

This meta-analysis, published in the Journal of Personalized Medicine, compiles data from seven randomised controlled trials (RCTs) totaling 2,324 participants, to evaluate the clinical performance of various TMVR options. The objective is twofold: to compare all-cause mortality and heart failure rehospitalization rates between TMVR groups and control treatments (surgery or OMT), while ranking percutaneous strategies. The hypothesis tested here is that TMVR, particularly the edge-to-edge technique with the MitraClip device, offers a significant benefit on clinical outcomes, particularly in patients with functional MR, thus paving the way for a more rigorous personalized therapeutic approach in practice.

Study methodology

This meta-analysis and network meta-analysis, conducted according to the PRISMA protocol, examined the clinical efficacy of transcatheter mitral valve repair (TMVR) strategies compared to conventional surgery or optimal medical therapy (OMT). The literature search was performed in the PubMed, EMBASE, Medline, and ClinicalTrials.gov databases up to September 2024.

Inclusion and exclusion criteria

• Inclusion: Randomised controlled trials (RCTs) comparing at least one TMVR strategy to another treatment or control therapy (surgery or OMT), including patients presenting with symptomatic mitral regurgitation of grade ≥ 2+.
• Exclusion: Registries, single-arm studies, cohort studies, publication duplicates, articles published in languages other than English, and data derived from post-hoc analyses of RCTs.

Analysis protocol

The risk of bias assessment was performed by two independent investigators using the Cochrane RoB 2 tool, with arbitration by a third researcher in case of disagreement. The primary endpoint defined was all-cause mortality. Secondary endpoints included heart failure rehospitalizations, mitral valve reinterventions, recurrent mitral regurgitation (grade ≥ 3+), and NYHA score (class III/IV). Data pooling was performed using a Mantel–Haenszel random-effects model to calculate risk ratios (RR) with 95% confidence intervals.

Results: Clinical impact of TMVR

This meta-analysis synthesized data from 7 randomised controlled trials, totaling 2,324 participants, to compare transcatheter mitral valve repair (TMVR) strategies to conventional treatments (surgery or optimal medical therapy). The median follow-up duration was 14 months.

The compiled data demonstrate a significant clinical benefit of TMVR compared to the control group, both in terms of mortality and cardiac morbidity.

Endpoint	Relative Risk (RR)	95% CI	p-value
All-cause mortality	0.77	0.65–0.91	0.002
Readmission for heart failure	0.67	0.49–0.91	0.01

The network analysis, aiming to compare different TMVR strategies with each other, suggests that edge-to-edge repair using the MitraClip system stands out as the potentially most effective option for reducing all-cause mortality.

The synthesis highlights that these results primarily concern patients with functional mitral regurgitation (FMR). While TMVR is established as a robust alternative, the authors note that current literature still lacks direct comparative data to define the optimal strategy specifically for patients with degenerative mitral regurgitation (DMR).

Confirmed efficacy for TMVR

This meta-analysis, covering seven randomized trials totaling 2,324 participants, confirms the superiority of transcatheter mitral valve repair (TMVR) over conventional approaches (surgery or optimal medical therapy). With a median follow-up of 14 months, TMVR significantly reduces all-cause mortality (RR 0.77; 95% CI 0.65–0.91; p = 0.002) and the risk of rehospitalization for heart failure (RR 0.67; 95% CI 0.49–0.91; p = 0.01). Among the technical options analyzed, the MitraClip system stands out as a leading option to limit mortality.

Clinical limitations and perspectives

The analysis highlights a predominance of patients with functional mitral regurgitation (FMR) in the included cohorts. While the results are robust for this population, extrapolation to degenerative forms (DMR) remains limited by the small number of specific trials. The heterogeneity of devices, ranging from edge-to-edge repair (TEER) to indirect annuloplasty, also complicates direct comparison of long-term performance. This study provides an essential synthesis but underscores the urgent need for comparative trials specifically dedicated to DMR to refine therapeutic choices.

Synthesis of clinical results

This meta-analysis of 7 randomized trials (2,324 participants) demonstrates that transcatheter mitral valve repair (TMVR) significantly reduces all-cause mortality (RR 0.77; 95% CI 0.65–0.91; p = 0.002) and rehospitalizations for heart failure (RR 0.67; 95% CI 0.49–0.91; p = 0.01) compared to medical or surgical treatment, particularly in functional mitral regurgitation. The MitraClip device stands out as the most effective option for mortality reduction.

In practice, for the clinician:

• Therapeutic orientation: Prioritize TMVR for symptomatic patients suffering from functional mitral regurgitation, due to the proven benefit on survival and hospitalization rates.
• Device choice: The edge-to-edge system (MitraClip) remains the gold standard for reducing mortality in this cohort.
• Caution regarding etiology: For degenerative mitral regurgitation, current evidence remains limited; the choice must be based on a personalized multidisciplinary discussion while awaiting more robust comparative data.

"lexicon": [ Transcatheter Mitral Valve Repair (TMVR)", "definition": "Less invasive therapeutic strategy including edge-to-edge repair and percutaneous annuloplasty, used as an alternative to surgical or optimal medical treatment." }, Functional Mitral Regurgitation (FMR)", "definition": "Type of mitral regurgitation whose natural history and clinical outcomes differ from the degenerative form, representing the majority of patients included in the analyzed clinical trials." }, Degenerative Mitral Regurgitation (DMR)", "definition": "Pathology of the mitral valve, distinct from the functional form, for which data from randomized controlled trials are more limited, justifying further research." }, Edge-to-edge repair", "definition": "Percutaneous repair technique based on the principle of approximating the leaflets of the mitral valve, illustrated in particular by the MitraClip device." }, Percutaneous annuloplasty", "definition": "Transcatheter mitral repair therapeutic option, such as the Carillon device, aimed at treating mitral regurgitation in a less invasive manner than conventional surgery." }, Optimal Medical Therapy (OMT)", "definition": "Non-surgical reference treatment used as a control group in randomized trials comparing the efficacy of transcatheter interventions." }, All-cause death", "definition": "Primary endpoint of this meta-analysis, used to evaluate the comparative performance of therapeutic strategies in patients suffering from symptomatic mitral regurgitation.

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