The AV complex is composed of four rings: the virtual annulus, the anatomic annulus, the sino-tubular junction and a crown-like ring from the cusps (Figure 12). What we measure as the AV annulus is the virtual ring which is also the hinge-point of the AV cusps. As shown in Figure 13, the orientation of the typical 2D parasternal long axis view that displays the commissure between right and non-coronary cusps (red arrow) does not show the maximum diameter of the annulus (blue arrow).

3D TEE can be very useful in accurately sizing the annulus because aligning the short-axis view of the AV to present the true annulus allows the assessment of its circularity and the measurement of the maximum diameters (Figure 14).

Measurement of the distance from the annulus to the left main coronary ostium requires 3D TEE as the left main coronary artery ostium lies in the coronal plane which cannot be acquired by standard 2-D imaging (Figure 15). In general, a distance of >10 mm is desirable for the 23 mm balloon expandable valve and a distance of >11 mm is desirable for the 26 mm valve. This measurement is not necessary for the self-expanding prosthetic aortic valve.

Live 3D imaging however increases the “field of view” and frequently improves localization of the crimped valve margins within the aortic valve apparatus (Figure 16). The biplane view that provides complementary 2-D planes is also very helpful in monitoring valve positioning and deployment (Figure 17).

3D TEE is most useful immediately following valve deployment for accurate assess of the position and function of the valve including identifying the presence/severity of aortic regurgitation (Figures 18 and 19). Significant regurgitation may be an indication for repeat balloon inflation to attempt maximal expansion of the valve.

Paravalvular regurgitation (PVR) after surgical valve replacement is typically associated with dehiscence of sutures and may result from infection, annular calcification, friable/weak tissue at the site of suturing or technical factors at the time of implantation. Most commonly encountered with mitral prostheses, paravalvular leaks may be associated with hemodynamically significant regurgitation causing heart failure and/or hemolysis. Because reoperation for PVR is associated with an increased likelihood of a recurrent leak as well as surgical morbidity and mortality, transcatheter closure is appealing.

Echocardiography has proven essential in paravalvular leak closure with both TEE and intracardiac echocardiography (ICE) used to guide these procedures. 3D TEE is now considered the preferred TEE imaging modality as it is uniquely capable of demonstrating the irregular (frequently crescentic) shape of the defects and is better able to identify multiple defects and provide accurate sizing.