Off-pump mitral valved stent implantation guided by Real-Time 3D-Transesophageal Echocardiography

Objectives: Real-time three-dimensional transoesophageal echocardiography (RT 3D TEE) guidance has been reported previously for different cardiac interventions. In this study we report our experiences during mitral valved stent implantation based on guidance and evaluation using the new technique of RT 3D TEE.

Methods: Transapical mitral valved stent implantation in the beating heart was performed in 12 pigs under RT 3D TEE and common two-dimensional (2D) TEE guidance. A full TEE evaluation was conducted before and after implantation as well as a follow-up at one month to assess heart function, valved stent position and performance, paravalvular leakage (PVL) and central regurgitation.

Results: All animals were implanted on first attempt, one died during the implantation procedure due to ventricular fibrillation, 11 have been successfully implanted and four pigs have been followed-up for one month. 3D TEE provided dependable spatial visualization of the left heart, mitral apparatus, delivery system, and valved stent. It was an adequate method for correct positioning of the mitral valved stent in all cases. No further visualization techniques such as fluoroscopy were required. RT 3D TEE notably facilitated orientation for the surgical team as well as positioning of the device especially in comparison to 2D imaging. TEE evaluation showed normal mean gradients (Pmean[mmHg] Pre: 0.17 ± 0.33 Post: 1.03 ± 0.46 1 month: 1.25 ± 0.96) and velocities (PW: Vmax[cm/s] Pre: 62.63 ± 12.34 Post: 90.10 ± 16.90 1 month: 106.88 ± 59.39) over the mitral valve). Ejection fraction slightly decreased after implantation (EF[%] Pre: 63.82 ± 6.10 Post: 53.21 ± 10.17 1 month: 55.39 ± 15.41). During evaluation of the stent performance, the RT 3D-mode was particularly suitable for visualization of the stent movement and deformation. Assessment of central mitral regurgitation (MR) and PVL was facilitated by the use of RT 3DTEE. MR was trace in five, mild in one and none in all remaining animals; PVL was trace in four, mild in one and non in the remaining animals directly after implantation.

Hence RT 3D TEE contributed very positively to the successful minimally invasive implantation of this new device into the native mitral annulus.

Conclusions: RT 3D TEE provided accurate views and allowed assessment of regurgitations as well as three-dimensional imaging of the stent position and function. It proved to be of great value as a guidance method during implantation of this innovative cardiac device.