Before the procedure to define true severity of the aortic stenosis and to measure the annulus dimensions. This is performed by means of 3D TEE (Table 7.1). Acquisition is performed in the short axis view of the aortic valve (45ª) and in the left ventricular outflow tract view (120°). Normally 3D zoom modality is used with adjustment of the lateral and vertical width to assure that the complete annulus, left ventricular outflow tract and proximal ascending aorta is included. Temporal resolution should be optimized as much as possible with at least 10 volumes/second. This is easily achieved in 1 single beat acquisition mode if the volume is adjusted to the aortic annulus. In some cases however, high volume rate acquisition can be used but spatial resolution and image quality for measurements will decrease. Since the aortic valve in these patients is extensively calcified we recommend acquiring 3D images in both planes so possible limitations due to calcium acoustic shadow are reduced. Multiplane reconstructions from 3D volume acquired are used for both aortic valve area and annulus measurements. Perpendicular adjustment of the reference planes at the level of narrowest valve opening in systole allows aortic valve area tracing (Fig. 7.5). Different papers have shown the superiority of 3D valve area planimetry over 2D in determining aortic stenosis severity. This measurement has also shown a good correlation with both continuity equation valve area and hemodynamic vale area assessment. In the same multiplane images, the image plane can be moved down to the aortic annulus where both diameters, area and perimeter can be easily measured. AV annulus dimensions are measured from the hinge point of the right coronary cusp to the anterior aortic wall, perpendicular to the long axis of the aortic root, in mid-systole where its diameter is at its maximum (Figs. 7.6 and 7.7) Since the aortic annulus is not circular but rather elliptical, 3D sizing of the aortic annulus is superior to the 2D assessment that gives only the sagittal smaller diameter. Different papers have shown the superiority of 3D annulus assessment, both with TEE or computed tomography over 2D [8, 9]. Annulus sizing is more accurate and this translates in better results, reducing the rate of paravalvular regurgitation [10]. Additional information obtained from 3D images are the distance to the right and left main coronary arteries, level of calcification and severity of mitral regurgitation.

During the procedure, both 2D and 3D TEE imaging are used. 3D overcomes some of the limitations encountered with 2D; it provides a better visualization of the wires and catheters and both real time orthogonal biplane and 3D imaging helps in different steps of the procedure (Table 7.2). Crossing the stenosed aortic valve may be difficult in some case, real time 3D imaging provides an “en face” view of the valve and may help in this task along with biplane imaging. In the long axis left ventricular outflow tract view, 3D real time imaging allows visualization of wire, valvuloplasty balloon position, inflation and results (Fig. 7.8). In the same way, prostheses advance and positioning is also possible, providing a better delineation of the balloon and prostheses for optimal positioning in the aortic annulus. Edward-Sapiens valve optimal position is 2–4 mm bellow the aortic annulus plane, while Core Valve should be place 5–10 mm bellow [6, 7, 2] After deployment, evaluation of prostheses position, leaflet movement and presence and degree of valvular regurgitation is needed. In this way, assessment of both prostheses position and leaflet movement can be performed with 2D and 3D imaging (Video 7.2). 3D imaging, both real time or zoom 3D allows multiplanar reconstructions in cases where prostheses mal function is suspected or limited evaluation is achieved with 2D echo. Both valvular and paravalvular regurgitation is better evaluated with 3D echo. First biplane simultaneous visualization of the aortic prostheses in the short and long axis view is possible and a first approach to the extension and location of the aortic regurgitation is performed (Fig. 7.9). Color 3D acquisition with 3D zoom modalities allows multiplanar reconstruction to assess origin and size of the regurgitant jet or jets as well as its extension in the annular ring. Vena contracta area can be measured avoiding the limitation of 2D assessment of the regurgitant jets. The VARC recommendations suggest that for paravalvular jets, the proportion of the circumference of the sewing ring occupied by the jet gives a semi-quantitative guide to severity: <10% of the sewing ring suggests mild, 10–29% suggests moderate, and ≥30% suggests severe [11]. This is essential during the procedure because in some cases depending on the degree of valvular regurgitation and prostheses position post-dilatation may be needed. Once prostheses correct position and function is confirmed and before ending the procedure mitral regurgitation severity, left ventricular segmental wall motion, pericardial effusion and aortic wall assessment should be performed to rule out other more rare complications of the procedure.

Comprehensive assessment of mitral valve is mandatory before MitraClip procedure. 3D TEE overcomes many of the limitations of 2D echocardiography and has proved to be superior in many clinical conditions. Main advantages of 3D TEE in MitraClip patient selection are the evaluation of mitral regurgitation severity and mitral valve morphology [14, 15]. In the first case, direct measurement of the proximal isovelocity surface area and vena contracta without geometric assumptions with 3D TEE, improves accuracy [16, 17]. This is particularly relevant when dealing with functional MR.The asymmetrical deformation of the valve apparatus will generate non-spherical and more funnel-like regurgitant orifices encompassing the coaptation closure line, which can only be completely visualized with 3DTEE. A first color zoom 3D acquisition including the entire mitral valve is normally performed to localize the regurgitant jet; this is very important, since optimal jet origin should be between A2 and P2 segments, being eccentric or more complex jets less suitable. Subsequent, a smaller volume centered in the regurgitant jet (excluding part of the mitral annulus) is acquired with higher temporal resolution for mitral regurgitation vena contracta area analysis (Figs. 7.10 and 7.11). Different papers have shown the higher accuracy of this method compared to 2D TEE evaluation. In the second case, for MV morphologic evaluation, same 3D zoom image offers the advantage of visualization a highly detailed image of the whole MV in a single view (Video 7.3), which can then be rotated and angulated in all image planes; furthermore, additional en face views of the MV from both the LV and LA can be obtained [18]. It has been demonstrated that 3DTEE is more accurate in identifying valve segments compared with 2DTTE as well as clefts, gaps and perforations, frequently missed in 2DTEE. The evaluation of these images allows planning of the procedure, to locate the exact place of maximal mitral regurgitation or even plan a strategy of two clips in cases where mitral regurgitation is very large. Also mitral valve area evaluation by means of planimetry from 3D images (Fig. 7.12) is essential since valve areas bellow 3 cm² are a contraindication for the procedure (Table 7.3).