Original article
Adult cardiac
Transapical Mitral Valved Stent Implantation

https://doi.org/10.1016/j.athoracsur.2008.05.039Get rights and content

Background

Transcatheter aortic and pulmonary valve replacement is currently being tested in human trials. Efforts to create a valved stent to replace the atrioventricular valves have shown limited success. This is due to their their complex anatomy and function.

Methods

A self-expanding valved stent was created for transapical replacement of the atrioventricular valve. Ten pigs underwent transapical off-pump mitral valved stent implantation. Data were gathered to assess the animals' hemodynamic stability for 60 minutes after implantation. The valved stent function was assessed by transesophageal echocardiography (TEE) and contrast left ventriculogram.

Results

All animals exhibited normal hemodynamics immediately after mitral valved stent implantation and maintained stability for the entire period of monitoring. Accurate positioning of the valved stent was established in all animals. Mild paravalvular regurgitation was found in three out of ten animals by TEE and in two animals during left ventriculogram. No left ventricular outflow tract obstruction was encountered.

Conclusions

Transapical off-pump mitral valved stent implantation is feasible in an acute experimental setting. Long-term function of the new valved stent remains to be established.

Section snippets

Material and Methods

A self-expanding valved stent intended for transapical implantation into an atrioventricular heart valve was constructed. The new valved stent has three components: (1) an atrial fixation system consisting of ultrathin high-density polyester covered metal springs (35 to 48 mm); (2) a ventricular body made of a nitinol self-expanding stent (Nitinol Devices & Components, Fremont, CA) that accommodates a bioprosthetic heart valve (diameter, 25 to 32 mm); and (3) a ventricular fixation system.

Results

Procedural data are listed in Table 1. All animals exhibited normal hemodynamics immediately after mitral valved stent implantation and maintained stability for the entire 60 minutes of monitoring. Atrial and ventricular ectopic beats occurred during preparation of apical access and during valve deployment in all animals. No sustained or hemodynamically relevant arrhythmias were recorded. The mean mitral valve annular diameter was 23.3 mm, ranging from 21 to 27 mm. Surgical preparation of

Comment

In the current study most of the difficulties related to valved stent implantation in the mitral position were avoided. Transesophageal echocardiography allowed satisfactory visualization to guide the transapical mitral valved stent implantation. Radial force in the current stent design was used mostly for stent expansion and had only a minor role in anchoring the stent, which eliminated the risk of LVOT obstruction either directly or by SAM. In our experiments the chordae tendineae only

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These authors contributed equally to this manuscript.

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