New registry data on a key mitral valve procedure shows mixed results. A large US study found that LAMPOON — a technique used to prevent a dangerous complication during transcatheter mitral valve replacement — had acceptable 30-day mortality for valve-in-valve and valve-in-ring cases, but significantly higher mortality for patients with mitral annular calcification. Experts are now calling for a center-of-excellence model to concentrate this complex procedure.
New real-world data from the STS/ACC TVT Registry is giving clinicians the clearest picture yet of how the LAMPOON technique is being used — and how patients are faring — across the US. LAMPOON, which involves lacerating the anterior mitral leaflet to prevent life-threatening left ventricular outflow tract (LVOT) obstruction during transcatheter mitral valve replacement (TMVR), was performed in 8.9% of nearly 9,250 TMVR cases at 569 sites between 2019 and 2025.
Outcomes varied significantly by valve anatomy. Thirty-day all-cause mortality was 8.3% for valve-in-valve (ViV) and 6.1% for valve-in-ring (ViR) patients — deemed "acceptable" given their surgical risk scores — but jumped to 23.7% for patients with mitral annular calcification (ViMAC). One-year mortality exceeded 40% in the native-valve cohort. LVOT obstruction was avoided in 95.5% of all LAMPOON patients, underscoring the technique's effectiveness at its primary goal.
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Why it matters: These findings highlight that while LAMPOON is expanding access to TMVR for high-risk patients, outcomes remain highly dependent on underlying anatomy. Experts are calling for a center-of-excellence model to ensure this technically demanding procedure is concentrated at high-volume sites — where volume-outcome relationships can be better studied and patient selection refined.
