In patients with atrial functional mitral regurgitation (AFMR), transcatheter edge-to-edge repair (TEER) has similar efficacy and better safety profile than mitral valve surgery, according to a post-hoc analysis from the MATTERHORN trial. These data were reported by Stephan Baldus, MD, of the University Hospital Cologne, Cologne, Germany, and colleagues on Wednesday at the Transcatheter Cardiovascular Therapeutics (TCT) 2024 meeting in Washington, DC, simultaneously published in Circulation. The MATTERHORN (Multicenter Mitral Valve Reconstruction for Advanced Insufficiency of Functional or Ischemic Origin) trial demonstrated that TEER is non-inferior to mitral valve surgery in patients with heart failure and functional mitral regurgitation (FMR). While FMR typically results from left ventricular (LV) dysfunction (VFMR), it can also occur in patients with preserved ventricular function but with left atrial dilation, termed AFMR. Observational studies support TEER’s safety and efficacy in AFMR, though a prospective comparison with surgical therapy in this subgroup is still lacking. Study Details Baldus and colleagues aimed to demonstrate the noninferiority of TEER versus mitral valve surgery in patients with AFMR and VFMR using data from the MATTERHORN trial. MATTERHORN enrolled 208 patients and randomized 1:1 to TEER or surgery. AFMR was defined as LV ejection fraction ≥40%, normal LV size (LVEDV ≤85 ml/m² for males, ≤78 ml/m² for females), enlarged left atrium (volume index ≥40 ml/m²) and non-ischemic mitral regurgitation. Patients outside these criteria were classified as VFMR. The primary efficacy endpoint (PEE) included all-cause death, heart failure hospitalization, mitral reintervention, LV assist device placement or stroke within 1 year. The primary safety endpoint (PSE) included major adverse events within 30 days: death, myocardial infarction, major bleeding, stroke, rehospitalization, reintervention, unplanned cardiac surgery, renal failure, deep wound infection, prolonged ventilation, gastrointestinal surgery, new atrial fibrillation, septicemia or endocarditis. There were 34 AFMR patients (16 in TEER and 18 in the surgery group) and 174 VFMR patients (88 in TEER and 86 in the surgery group). At 1 year, PEE data were available for 91.2% of AFMR patients and 88.5% of VFMR patients. In the AFMR group, the PEE occurred in 21.4% of TEER vs. 29.4% of the surgery patients (p=0.058 for non-inferiority). For VFMR patients, the PEE occurred in 15.9% of TEER vs. 20.8% of surgery patients (p<0.001 for non-inferiority). The PSE at 30 days was 17.6% in TEER vs. 82.4% in the surgery group within AFMR patients (p<0.001), and 31.7% vs. 69.6% in the VFMR patients (p=0.002). All subgroups and treatment arms showed improved quality of life, with MLHFQ (Minnesota Living with Heart Failure Questionnaire) scores decreasing by a median of -6 after TEER vs. -13 after surgery in the AFMR patients and by a median of -11 after TEER vs. -4 after surgery in the VFMR patients. Putting these findings together, Baldus and colleagues concluded that in both AFMR and VFMR, TEER showed significantly lower 30-day PSE event rates, with similar efficacy at one year. However, they added that due to small AFMR sample sizes and non-prespecified subgroup analyses, these findings should be considered exploratory. Source: Rudolph F, Geyer M, Baldus S, et al. Transcatheter repair versus surgery for atrial versus ventricular functional mitral regurgitation – a non-prespecified post-hoc analysis of the MATTERHORN trial. Circulation (2024). DOI: 10.1161/CIRCULATIONAHA.124.072648 Image Credit: Stephan Baldus, MD, speaks during a news conference Wednesday at the Transcatheter Cardiovascular Therapeutics (TCT) conference in Washington, DC. Image Credit: Bailey G. Salimes, CRTonline.org