Page 20 - Advanced echocardiography in characterization and management of patients with secondary mitral regurgitation

Chapter one. General introduction and outline of thesis
Figure 7: Mitral annulus assessment with MDCT in preprocedural planning of transcatheter mitral valve replacement. The D-shape mitral annulus reconstruction is shown in panel a with the dotted line indicating the intertrigonal distance. Panel b shows the long-axis view of the left ventricular outflow tract (LVOT) and the mitral annulus with the highest point anteriorly in relation with the aortic root. The corresponding computed tomography sagittal view shows the simulation of a tubular transcatheter mitral valve fitted in the mitral annulus and showing the LVOT clearance (or neo-LVOT, shaded area).
More important is the prediction of LVOT obstruction when considering transcatheter mitral valve replacement and that can be performed by calculating the neo-LVOT area [16–18]. Blanke et al.[16] noticed that when considering the saddle-shaped mitral valve annulus, the clearance of the LVOT was smaller than when considering the D-shaped annulus. In addition, it is also important to establish how to measure the neo-LVOT. Meduri et al.[19▪▪] hypothesized that the current standard MDCT-assessment performed on end-systolic images might underestimate the neo-LVOT area. Of 33 patients considered for transcatheter mitral valve replacement who were screened for the Intrepid Global Pilot Study and had high risk of LVOT obstruction based on end-systolic measurements, 11 would have been eligible if the neo-LVOT area was measured throughout the entire cardiac cycle (multiphase average) or if the neo-LVOT area was measured at early systole. Therefore, the potential enrollment would have increased by 33% if multiphase average or early systolic measurements would have been performed. In addition, in nine patients who were considered having high risk of LVOT obstruction based on end-systolic assessment, the Intrepid valve was eventually successfully implanted after the multiphase average measurements showed that the area of the neo-LVOT was acceptable [19▪▪]. Prediction of LVOT obstruction is also important when transcatheter mitral valve replacement is considered for patients with failed mitral bioprosthetic valves (valve-in-valve), annuloplasty rings (valve- in-ring), and mitral annular calcification (valve-in-MAC). Yoon et al.[18] showed that patients undergoing valve-in-MAC had worse prognosis as compared with patients undergoing mitral valve-in-valve or valve-in-ring. On MDCT, these patients showed the smallest predicted neo-LVOT area, which was associated with LVOT obstruction
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