Intentional Laceration of the Anterior Mitral Valve Leaflet to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Replacement: Pre-Clinical Findings.
The authors propose a novel transcatheter transection of the anterior mitral leaflet to prevent iatrogenic left ventricular outflow tract (LVOT) obstruction during transcatheter mitral valve replacement (TMVR).



LVOT obstruction is a life-threatening complication of TMVR caused by septal displacement of the anterior mitral leaflet.



In vivo procedures in swine were guided by biplane x-ray fluoroscopy and intracardiac echocardiography. Retrograde transaortic 6-F guiding catheters straddled the anterior mitral leaflet. A stiff 0.014-inch guidewire with polymer jacket insulation was electrified and advanced from the LVOT, through the A2 leaflet base, into the left atrium. The wire was snared and externalized, forming a loop that was energized and withdrawn to lacerate the anterior mitral leaflet.



The anterior mitral leaflet was successfully lacerated in 7 live and 1 post-mortem swine under heparinization. Lacerations extended to 89 ± 19% of leaflet length and were located within 0.5 ± 0.4 mm of leaflet centerline. The chordae were preserved and retracted the leaflet halves away from the LVOT. LVOT narrowing after benchtop TMVR was significantly reduced with intentional laceration of the anterior mitral leaflet to prevent LVOT obstruction than without (65 ± 10% vs. 31 ± 18% of pre-implantation diameter, p < 0.01). The technique caused mean blood pressure to fall (from 54 ± 6 mm Hg to 30 ± 4 mm Hg, p < 0.01), but blood pressure remained steady until planned euthanasia. No collateral tissue injury was identified on necropsy.



Using simple catheter techniques, the anterior mitral valve leaflet was transected. Cautiously applied in patients, this strategy can prevent anterior mitral leaflet displacement and LVOT obstruction caused by TMVR.
Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
Jaffar M
JM
Khan
Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
Toby
T
Rogers
Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
William H
WH
Schenke
Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
Jonathan R
JR
Mazal
Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
Anthony Z
AZ
Faranesh
Center for Structural Heart Disease, Division of Cardiology, Henry Ford Health System, Detroit, Michigan.
Adam B
AB
Greenbaum
Structural Heart and Valve Center, Emory University Hospital, Atlanta, Georgia.
Vasilis C
VC
Babaliaros
Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
Marcus Y
MY
Chen
Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland. Electronic address: lederman@nih.gov.
Robert J
RJ
Lederman
D000818:Animals; D006328:Cardiac Catheterization / Q000009:adverse effects; D004452:Echocardiography; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000379:methods*; D006439:Hemodynamics; D007049:Iatrogenic Disease / Q000517:prevention & control*; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D023421:Models, Animal; D015641:Radiography, Interventional; D034421:Sus scrofa; D014694:Ventricular Outflow Obstruction / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*
left ventricular outflow tract obstruction; mitral valve; structural heart disease; subvalvular aortic stenosis; transcatheter mitral valve replacement; valvular heart disease