The LAMPOON procedure is an innovative, minimally invasive cardiac intervention designed to prevent a potentially fatal complication of TMVR: left ventricular outflow tract (LVOT) obstruction.

In some patients, when a new transcatheter heart valve is placed within the existing mitral valve or mitra bioprosthesis, the old anterior mitral leaflet or old bioprosthetic leaflet can be pushed into the left venticle’s outflow tract- LVOT there by blocking the forward blood flow leading to a potentially fatal complication of TMVR: left ventricular outflow tract (LVOT) obstruction.

The LAMPOON technique involves using a catheter and electrocautery to intentionally split (lacerate) the anterior mitral leaflet or the bioprosthetic leaflet before the new valve is deployed. This creates more space, ensuring the blood can flow freely out of the left ventricle.

• Retrograde (Classic) LAMPOON: This was the original approach. The anterior mitral leaflet is lacerated from its base (annulus) to its tip (free edge). This approach requires careful catheter positioning and a venoarterial wire rail, as there is a risk of injury to the nearby aortic valve and aortomitral curtain in native valves.
• Antegrade LAMPOON: This modification uses a trans-septal (femoral vein) approach, which offers greater catheter stability and a more direct path to the A2 scallop of the leaflet. The laceration is still typically performed from base to tip. This approach is generally considered less technically demanding than the classic retrograde method.
• Tip-to-Base LAMPOON: This is the simplest modification and is used specifically in patients who already have a protective structure, such as a prior surgical mitral annuloplasty ring or a bioprosthetic valve. This "backstop" prevents the laceration from extending dangerously into the aortic area, allowing the procedure to be performed from the leaflet tip toward the base without the need for the challenging leaflet traversal step required in other techniques.
• Rescue LAMPOON: This modification is essentially the tip-to-base technique used as a bailout strategy if LVOT obstruction occurs after an initial TMVR procedure, typically due to systolic anterior motion of a long leaflet.
• Balloon-Augmented (BA) LAMPOON: In cases of rigid or calcified leaflets, a balloon is used to dilate the traversal area immediately before laceration to augment leaflet splaying and ensure a more complete split.
• BATMAN (Balloon-Assisted Translocation of the Mitral Anterior Leaflet): This technique is considered a potentially simpler and faster alternative to LAMPOON. It uses electrosurgery for initial access to the anterior mitral leaflet (AML), followed by balloon inflation to physically tear and reposition the leaflet tissue, moving it out of the path of blood flow. It can be performed via transapical or transseptal approaches.
• Other variants of mitral leaflet modification: There are variations- CLEVE, DETROIT, SWATT, ROBIN, SUPERMAN, BLAST etc. The goal of all these modifications is the same: to create an effective, controlled split in the anterior mitral leaflet so that the new transcatheter heart valve can be safely implanted, preserving blood flow through the left ventricular outflow tract.
• Alternative: Septal modification by alcohol septal ablation, radiofrequency septal ablation, SESAME (Septal Scoring Along the Midline Endocardium)