TEE can aid balloon positioning during valvuloplasty, detect post-valvuloplasty aortic regurgitation, aid prosthesis positioning during implantation, confirm prosthesis function immediately post implantation and rapidly detect complications.

The optimal position for the Edwards SAPIEN™ Valve is with the ventricular side of the prosthesis positioned 2-4mm below the annulus in the left ventricular outflow tract. Examples of 2D TEE imaging during prosthesis positioning and deployment are shown in Figures 5 B and 5C.

The CoreValve™ has a different structure, the ventricular edge of the prosthesis should be placed 5-10 mm below the aortic valve annular plane. A normally positioned CoreValve™ is shown in Figure 6.

Immediately following deployment, TEE is used to confirm satisfactory positioning and function of the prosthesis (Figures 7A and 7B). This requires a combination of 2D imaging and Doppler evaluation with 3D also used if available. At this moment the assessment of complications is performed (Table 1).

When the prosthesis is positioned too low, it may impinge on the mitral valve apparatus (Figure 8) or it may be difficult to stabilize in patients with marked sub-aortic septal hypertrophy. The native valve cusps may also fold over the top of the prosthesis and impede its function. If the prosthesis is implanted too high, it may migrate up the aorta, obstruct the coronary ostia or be associated with significant paravalvular regurgitation.

Severe aortic regurgitation may occur as a consequence of incomplete expansion or incorrect positioning of the device, restricted cusp motion, or inappropriate prosthetic size. An undersized prosthesis is expected to be associated with paravalvular aortic regurgitation. In contrast, an oversized prosthesis may result in suboptimal stent expansion, impaired cusp mobility and central aortic regurgitation.