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Left ventricular outflow tract (LVOT) obstruction is a fatal consequence of transcatheter mitral valve replacement (TMVR). Despite advancements in transcather aortic valve replacement therapies, there currently exists no LVOT prediction model to optimize patient procedural safety in TMVR.
From 2013 to May 2016, 30 patients in 5 centers underwent TMVR with compassionate use of balloon-expandable valves for severe mitral valve dysfunction secondary to degenerative surgical mitral ring, bioprosthesis, or severe mitral stenosis secondary to severe mitral annular calcification. We performed a multi-center retrospective review of all thirty patients who underwent transcatheter mitral valve replacement. All patients had pre-procedural CT scans performed for LVOT prediction modeling, intraprocedural TEE and cardiac catheterization hemodynamics performed. Pre-procedural prediction modeling was performed utilizing computer-aided-design (CAD) modeling of the neo-LVOT post-TMVR.
All patients underwent successful transcatheter mitral valve replacement without device embolization. Five of the thirty patients experienced an increase of > 10mmHg in their LVOT peak gradient post-TMVR from their resting LVOT gradient. Utilizing an ROC curve comparing difference in LVOT peak gradient pre-and post-TMVR compared to predicted neo-LVOT surface area post-TMVR, a predicted neo-LVOT surface area of 252.2 mm2 (93.1% classification rate) was identified as the cutoff neo-LVOT surface area necessary for successful TMVR without an associated significant increase in LVOT peak gradients.
The novel clinical application of CAD design, and CT post-processing in predicting LVOT obstruction may be invaluable for optimal mitral valve annulus sizing, and determination of the desired deployment angulation and landing height. The use of this technology may improve the technical success of TMVR and aid in the first steps towards personalized medicine in transcatheter heart valve therapies.
IMAGING: Imaging: Non-Invasive