Mitral Valve Leaflet Modification: A Working Group Position Statement on Best Practices and Step-by-Step Guide.

Left ventricular outflow tract (LVOT) obstruction is a potentially lethal complication of transcatheter mitral valve replacement (TMVR). The risk for LVOT obstruction can reliably be identified on preprocedural cardiac computed tomography. Intentional LAMPOON (laceration of the anterior mitral leaflet to prevent LVOT obstruction) and related techniques effectively prevent TMVR-induced LVOT obstruction, thereby expanding the treatable patient population. However, perceived technical complexity, the absence of purpose-built devices, and limited training opportunities have hindered the widespread adoption of mitral leaflet modification. This document synthesizes international experience to provide contemporary best-practice guidance for mitral leaflet modification. This state-of-the-art review details transcatheter electrosurgery principles, computed tomography-based risk analysis and procedural planning, a step-by-step guide to the LAMPOON technique, tips for managing uncommon challenges, and guidance on postprocedural care. These contemporary best practices can help operators achieve or maintain proficiency.