Page 21 - Advanced echocardiography in characterization and management of patients with secondary mitral regurgitation

after transcatheter mitral valve replacement needing conversion to surgery and higher mortality. The neo-LVOT was computed at two device locations: where the device is largest in diameter and at the most ventricular portion of the device. The minimum value of the two measured locations was reported as the end-systolic minimum neo- LVOT area [19▪▪]. A substantial proportion of patients would have been not eligible for TMVR after this screening.
In addition, MDCT is useful to plan the transseptal and transapical implantation routes [14]. The transseptal puncture for mitral valve interventions is usually located 3.5–4 cm above the plane of mitral leaflet coaptation. From MDCT data, the multiplanar reformation planes can be aligned across the interatrial septum, the fossa ovalis can be detected and the transseptal puncture location can be drawn in a coaxial plane 3.5–4 cm above the mitral annulus [14]. The optimal fluoroscopic projection will be defined by the superimposition of the coaxial plane and the mitral annulus plane. For the planning of transapical procedures, the fusion of MDCT data and fluoroscopy helps to locate the puncture site with adequate distance from the left anterior descending coronary artery [20]. For transcatheter mitral valve replacement, the coplanar fluoroscopic projection angles that ensure a coaxial device deployment are derived from a compromise between the projection where the intertrigonal distance and the projection where the septal to lateral distance of the mitral annulus can be assessed. The mitral annular plane is oriented anterior and superiorly with pronounced tilting to the right leading to an S-shaped optimal projection curve that crosses the X axis (i.e., 0° cranio-caudal) at an average 38.8 ± 11.5° right anterior oblique [21].
Cardiac magnetic resonance
In the evaluation of mitral regurgitation, current guidelines recommend CMR when echocardiography is inconclusive in grading the severity of mitral regurgitation [22,23]. In the preprocedural planning of transcatheter mitral valve interventions, CMR is currently used in the assessment of mitral regurgitation severity and left ventricular volumes and function. Furthermore, CMR provides information on tissue characterization (myocardial scar/fibrosis) by using late gadolinium contrast-enhanced (LGE) techniques. However, the impact of myocardial scar/fibrosis assessment with LGE-CMR on the decision making remains unclear.
Quantification of the mitral regurgitant volume and fraction are the key parameters to assess the severity of mitral regurgitation. Several methods can be used to quantify the mitral regurgitant volume [24▪▪]:
(1) By calculating the difference between the left ventricular stroke volume measured
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