Long-term outcomes of transcatheter mitral valve repair in patients with cancer: a systematic review and meta-analysis.

Surgical and transcatheter mitral valve interventions are the mainstay of treatment for mitral regurgitation (MR). Their impact in patients with cancer has recently gained attention in observational studies but remains poorly characterized. We performed a systematic review and meta-analysis to evaluate outcomes of mitral valve interventions, with particular focus on M-TEER, in patients with active or prior cancer. PubMed and Scopus were systematically searched according to the PRISMA 2020 Statement. This systematic review was prospectively registered in PROSPERO (CRD420261368392). Studies reporting outcomes of transcatheter or surgical mitral valve interventions in patients with cancer were eligible. The primary outcome was all-cause mortality. Secondary outcomes included short-term mortality, procedural success, heart failure worsening or hospitalization, and reintervention. Hazard ratios (HRs) were pooled using random-effects models when appropriate. When HRs were not directly available, they were reconstructed according to established methods for time-to-event data synthesis. Eight observational studies met the inclusion criteria. Seven studies evaluated M-TEER, accounting for the vast majority of patients included in the quantitative analyses (1522 patients with cancer and 4716 controls), whereas only one study assessed surgical mitral valve intervention. In the pooled analysis of M-TEER studies, cancer was associated with a significantly higher risk of all-cause mortality during follow-up (HR 1.72, 95% CI 1.03-2.90; I2 = 74.8%). This association remained consistent across prespecified subgroup and sensitivity analyses. No significant differences were observed in 30-day mortality or procedural success between patients with and without cancer. Data on heart failure outcomes and reintervention were insufficient for quantitative synthesis. This study provides a quantitative synthesis of available evidence regarding long-term outcomes after M-TEER in patients with cancer. Patients with cancer undergoing M-TEER have higher long-term mortality than those without cancer, despite similar procedural success and short-term outcomes. These findings suggest the observed excess mortality occurs in patients with cancer but the available evidence does not establish the factors responsible for this association, which could be mediated by frailty, CV comorbidity, treatment-related comorbidity mitral regurgitation (MR) characteristics, or other residual confounders. Of note, studies comparing matched cohorts found a non-significant difference in HR for long-term mortality. Current evidence is limited by observational data and residual confounding. Prospective cardio-oncology studies are needed to improve patient selection and identify individuals most likely to benefit from transcatheter mitral valve intervention.