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Left ventricular outflow tract (LVOT) obstruction is a life-threatening complication of transcatheter mitral valve replacement (TMVR), caused by septal displacement of the anterior mitral valve leaflet (AML). We used a new catheter technique to split the AML and prevent iatrogenic LVOT obstruction immediately before TMVR.
The procedure was used in patients with severe mitral valve disease and prohibitive surgical risk. Patients either had prior surgical mitral valve ring (n=3) or band (n=1) annuloplasty or mitral annular calcification with stenosis (n=1). Iatrogenic LVOT obstruction or transcatheter heart valve dysfunction was predicted in all based on echocardiography and CT. Transfemoral coronary guiding catheters directed an electrified guidewire across the center and base of the AML towards a snare in the left atrium. The externalized guidewire loop was then electrified to lacerate the AML along the centerline from base to tip, sparing chordae, immediately before transseptal TMVR.
Five patients with prohibitive risk of LVOT obstruction or transcatheter heart valve dysfunction from TMVR successfully underwent LAMPOON, with longitudinal splitting of the A2 scallop of the AML, prior to valve implantation. Multiplane CT modelling predicted hemodynamic collapse assuming an intact AML. However, critical LVOT gradients were not seen following LAMPOON and TMVR. Doppler blood flow was seen across transcatheter heart valve struts that encroached the LVOT, because the AML was split. Transcatheter heart valve function was unimpeded.
This novel catheter technique, which resembles surgical chord-sparing AML resection, may enable TMVR in patients with prohibitive risk of LVOT obstruction or THV dysfunction. A US IDE trial is currently underway to assess the safety of this procedure.
STRUCTURAL: Valvular Disease: Mitral