Why is this study important?

• Mitral Transcatheter Edge-to-Edge Repair (m-TEER) achieves similar procedural safety and effective mitral regurgitation (MR) reduction in patients with and without mitral annular calcification (MAC).
• MAC is associated with worse clinical outcomes after m-TEER, identifying a higher-risk population despite comparable procedural success.

What question was this study supposed to answer?

Mitral annular calcification is frequently encountered in patients with significant mitral regurgitation and has historically been associated with increased procedural complexity and uncertainty regarding outcomes after transcatheter therapies. As m-TEER has become more widely adopted, there remains limited large-scale evidence clarifying whether MAC impacts procedural success, safety, and longer-term clinical outcomes. The EXPANDed trial was designed to evaluate outcomes of m-TEER in patients with and without MAC in a large, contemporary cohort, addressing this key evidence gap.

What did the study show?

In this analysis of more than 2,000 patients undergoing m-TEER, procedural success, including reduction in mitral regurgitation and overall safety, was similar between patients with and without MAC. However, compared with the non-MAC group, patients with MAC experienced higher rates of heart failure hospitalization and increased 1-year mortality. Importantly, within the MAC cohort, patients with higher surgical risk (elevated STS scores), larger left ventricular volumes, and reduced ejection fraction had the highest observed mortality.

These findings suggest that while m-TEER is feasible and effective in MAC patients, MAC identifies a higher-risk phenotype, particularly when combined with advanced ventricular remodeling and elevated baseline surgical risk, warranting closer surveillance and more tailored post-procedural management.