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Minimally Invasive Mitral Valved-Stent Implantation using an Off-Pump Technique
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Veröffentlicht: | 26. April 2013 |
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Introduction: Off-pump implantation of a valved stent into the mitral position is in the focus of recent research. This innovative technique might allow the treatment of multi morbid patients suffering of severe mitral regurgitation, which are currently not compliant to open heart surgery and are hence denied surgery in many cases. This study presents a novel self-expanding valved stent designed for implantation into the mitral position in the beating heart.
Material and methods: The novel valved stent consists of an atrial element, a tubular ventricular body accommodating a bioprosthetic heart valve and a ventricular fixation system (Figure 1 [Fig. 1]). Eight pigs received a valved stent into the mitral position via transapical approach. Hemodynamic stability, stent function and positioning were assessed before (n=8), 1h after implantation (n=7) and one month (n=6) using transesophageal echocardiography (TEE). Cardiac computed tomography (CT) was performed after 10 days (n=6).
Results: One animal died of cardiac fibrillation during the implantation procedure and one animal died due to unrecognized inadequate valved stent positioning. Reliable stent stability and good positioning was achieved in the remaining six animals. TEE examination showed no significant mitral regurgitation and minimal gradients across the new valve and the LVOT. CT examination showed correct stent position, full stent expansion and minor deformation of the ventricular body. Large deformation of the stent geometry was observed at the junction between ventricular and atrial element in all cases. Gross evaluation of the six pigs demonstrated correct stent positioning, good ingrowths of the atrial element after one month (50%) and no thrombus formation (Figure 1 [Fig. 1]).
Conclusion: Reliable stent stability, minimal gradients and adequate stent function were seen throughout the study at a high degree of reproducibility, over a post-operative period of up to two months. The prospective focus will pertain to stent design, aiming at enhanced durability of the valved-stent components.