Balloon-assisted laceration and snaring technique (BLAST) of the anterior mitral leaflet to prevent LVOT obstruction during transcatheter mitral valve implantation: A novel leaflet modification technique

Introduction

Left ventricular outflow tract (LVOT) obstruction is a serious complication during transcatheter mitral valve implantation (TMVI) for different indications including in patients with prior mitral bioprosthetic valve replacement. Our case introduces a novel hybrid approach using balloon-assisted laceration and snaring technique (BLAST) of the anterior mitral leaflet (AML) to prevent LVOT obstruction in a high-risk patient with bioprosthetic valve dysfunction.

Case presentation

A 79-year-old woman with a history of hypertension, heart Failure with preserved ejection fraction (HFpEF), atrial fibrillation (on warfarin), mitral bioprosthetic valve replacement with 29 mm Mosaic valve in 2013 for severe rheumatic mitral stenosis and TAVR (transcatheter aortic valve replacement) for severe aortic stenosis (AS), presented with severe decompensated heart failure. Echo showed severe bioprosthetic dysfunction with mitral regurgitation (MR) due to flail bioprosthetic leaflet and perforation of the neoanterior leaflet. The patient was treated with multiple vasopressors and diuretics for stabilization prior to being transferred for TMVI as she was deemed prohibitive risk for surgery.

Preprocedural CT imaging predicted neoLVOT area of 133 mm² raising concerns for LVOT obstruction during valve implantation. The predicted LVOT after leaflet modification was 219 mm². Given the complexity of the case, to avoid possible LVOT obstruction, the decision was made to perform a balloon-assisted laceration and snaring of the neoanterior mitral leaflet. After proposed BLAST procedure through a trans-septal approach, a successful TMVI was performed. The peak LVOT gradient post procedure was 9 mmHg. Our patient was stable post-procedure, weaned from vasopressors, and showed significant hemodynamic and clinical improvement in the hospital and at short-term clinic follow-up.

Discussion

LVOT obstruction is a well-known challenge in TMVI, in patients with prior mitral valve replacement, annuloplasty or significant annular calcification. Techniques like LAMPOON have been used to prevent LVOT obstruction, but in complex cases, additional strategies may be necessary. The balloon-assisted laceration and snaring technique (proposed acronym BLAST) provides an effective and controlled method to address neoanterior leaflet dynamics. This modification may reduce procedural complexity and improve outcomes by ensuring that the LVOT remains unobstructed during valve deployment. This technique could complement or serve as an alternative to LAMPOON, particularly in redo TMVI cases.

Conclusion

The BLAST procedure demonstrates a promising approach for patients at high risk of LVOT obstruction during TMVI. Further studies are needed to validate the broader application and long-term benefits of this technique.