M-TEER and cancer: a technical success but increased long-term mortality

Management of mitral regurgitation in oncology patients: a persistent challenge

The prevalence of valvular pathologies in patients with a history of cancer or active malignant disease is raising growing concerns in clinical practice. Although mitral interventions, particularly percutaneous (M-TEER), have become therapeutic standards for mitral regurgitation, their long-term safety and benefit profile in this fragile population remains insufficiently documented. Cancer, due to its systemic nature, potentially cardiotoxic treatments, and the frailty it induces, could alter the post-interventional prognosis beyond immediate technical success.

This meta-analysis, registered under PROSPERO reference CRD420261368392, specifically aims to address this lack of data. The objective is to rigorously evaluate clinical outcomes—focusing on all-cause mortality—in cancer patients who have undergone a mitral valve intervention, whether surgical or, more broadly, via M-TEER. The authors sought to determine whether the presence of cancer significantly influences long-term survival while examining procedural feasibility and 30-day safety, in order to better guide patient selection in cardio-oncology.

Study design and framework

This study constitutes a systematic review and meta-analysis, prospectively registered on PROSPERO (CRD420261368392) and conducted according to PRISMA 2020 guidelines. The authors queried the PubMed and Scopus databases to identify studies evaluating surgical or percutaneous (M-TEER) interventions on the mitral valve in patients with a diagnosis of active or prior cancer.

Population and inclusion criteria

Eight observational studies met the eligibility criteria. The final corpus analyzes a total cohort of 1,522 cancer patients compared to 4,716 controls. Among the included studies, seven focused exclusively on M-TEER, while only one study analyzed mitral surgery.

Analysis methods

• Primary endpoint: All-cause mortality during follow-up.
• Secondary endpoints: 30-day mortality, procedural success, worsening heart failure, hospitalization, and reinterventions.
• Statistics: Hazard Ratios (HR) were pooled using random-effects models. For studies not reporting direct HRs, reconstruction methods were applied to synthesize time-to-event data.
• Bias assessment: The quality of the studies was scrutinized, with specific mention of statistical heterogeneity (I² = 74.8%).

Analysis of results: M-TEER and oncology

The synthesis of data compiled by the authors highlights a marked disparity in the long-term prognosis of oncological patients undergoing percutaneous mitral repair (M-TEER). Although procedural success is comparable to that of non-cancer patients, overall mortality is significantly higher in the group with neoplasia.

The heterogeneity of the included studies is notable, with an I² index calculated at 74.8%. The association between cancer status and the risk of death remained robust during pre-specified subgroup and sensitivity analyses. It is, however, crucial to note that, in studies using matched cohorts, the difference in long-term mortality risk did not reach the threshold of statistical significance.

Clinically, the available data remain insufficient to precisely quantify the impact on the progression of heart failure or the reintervention rate. The authors emphasize that, while the excess mortality is evident, the mediating factors remain to be elucidated:

• Intrinsic patient frailty.
• Pre-existing cardiovascular comorbidities.
• Toxicity related to oncological treatments.
• Specific characteristics of mitral regurgitation.

In summary, M-TEER intervention offers equivalent immediate safety in cancer patients, but the long-term survival benefit remains burdened by the prognosis of the underlying malignant pathology or its therapeutic sequelae.

M-TEER and oncology: what long-term prognosis?

This meta-analysis, registered under number CRD420261368392, highlights a major clinical paradox for the interventional cardiologist. While the procedural success of mitral transcatheter edge-to-edge repair (M-TEER) is comparable in patients with or without a history of neoplasia, long-term outcomes diverge significantly. The compiled data indicate that cancer remains an independent risk factor for excess mortality, with a pooled Hazard Ratio (HR) of 1.72 (95% CI 1.03–2.90).

This survival disparity raises questions: the technical procedure is effective in the short term, but it is not sufficient to erase the weight of oncological comorbidity. Should this be viewed as the impact of frailty, toxicities related to anticancer treatments, or underlying cardiovascular comorbidities? The current synthesis does not yet allow for a definitive conclusion, especially since studies comparing matched cohorts sometimes suggest non-significant results, testifying to a persistent selection bias.

The study nevertheless presents clear limitations: the heterogeneity of the data (I² = 74.8%) and the observational nature of the eight included works require cautious interpretation. There is also a lack of robust data on hospitalizations for heart failure, which limits our precise understanding of the post-intervention functional benefit in this specific population.

Summary of results

This meta-analysis, covering 8 observational studies (1522 cancer patients and 4716 controls), reveals that M-TEER in oncological patients compromises neither procedural success nor 30-day mortality. However, these patients exhibit significant long-term excess mortality compared to controls (HR 1.72; 95% CI: 1.03–2.90).

Specifically, for the practitioner:

• Prognostic caution: M-TEER is technically feasible with success in cancer patients, but the long-term survival benefit is tempered by the underlying malignant pathology.
• Multidisciplinary evaluation: Integrate a rigorous assessment of frailty and cardiovascular comorbidities before the procedure, as these factors appear to play a key role in the observed mortality.
• Patient selection: Pending dedicated prospective studies, prioritize M-TEER for the symptomatic relief of heart failure, while adjusting family and clinical expectations regarding overall survival.

Technical glossary: Meta-analysis on mitral valve interventions in cardio-oncology

M-TEER: Mitral Transcatheter Edge-to-Edge Repair. Percutaneous interventional technique used to treat mitral regurgitation; predominant in the study sample, constituting the primary treatment evaluated in oncological patients.

Systematic review and meta-analysis: Rigorous methodology compliant with the PRISMA 2020 standard, consisting of an exhaustive search on PubMed and Scopus to identify and synthesize data from observational studies on mitral interventions in an oncological context.

HR (Hazard Ratio): Instantaneous risk ratio measuring the association between the presence of cancer and all-cause mortality during follow-up; statistically reconstructed from survival data in the study.

All-cause mortality: Primary endpoint of the study, analyzed to evaluate the long-term impact of valvular interventions in oncological patients compared to controls.

Random-effects model: Statistical approach used in meta-analysis to combine the HRs of the different included studies, taking into account potential heterogeneity between the studied populations.

Time-to-event data: Type of clinical data analyzed for which HRs were calculated or reconstructed, allowing for the evaluation of mortality kinetics according to oncological status.

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