skip to main content

MAC Challenges for TMVR — EECC MCQ

Instant feedback + full explanation. One question, done properly.

HardValvular Heart DiseaseMAC Challenges for TMVREECC

A 75-year-old man with severe calcific mitral annular calcification (MAC) and mitral stenosis (MVA 1.0 cm²) is too frail for surgery (STS-PROM 15%). His echocardiographer notes the MAC extends to involve the LV outflow tract. What specific challenge does MAC pose for transcatheter mitral valve interventions?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — MAC creates a rigid, non-compliant landing zone for transcatheter valves with high risk of paravalvular leak, LVOT obstruction (from the valve frame protruding into the LVOT), and annular rupture — currently an evolving area with limited evidence

MAC poses unique challenges for transcatheter mitral valve replacement (TMVR): (1) rigid, irregular landing zone: unlike rheumatic MS (soft tissue commissural fusion), MAC creates a hard, calcified ring that cannot be dilated — making device sizing and anchoring difficult; (2) LVOT obstruction: the anterior extension of MAC into the LVOT (common) means a transcatheter valve frame may protrude anteriorly, causing LVOT obstruction — predicted by neo-LVOT area assessment on CT (< 2 cm² indicates high obstruction risk); (3) annular rupture: balloon dilation of the calcified annulus can cause catastrophic rupture; (4) paravalvular leak: irregular calcium preventing complete seal. The 2025 ESC VHD Guidelines acknowledge TMVR-in-MAC as an evolving procedure with limited evidence, performed only at highly experienced centres within clinical trials or compassionate use. LAMPOON (Laceration of the Anterior Mitral valve leaflet to Prevent Outflow Obstruction during TMVR) is a technique developed to mitigate LVOT obstruction.

Reference: ESC/EACTS (2025): VHD Guidelines