Transapical Mitral Valved Stent Implantation

University of Wisconsin–Madison, Madison, Wisconsin, United States
The Annals of thoracic surgery (Impact Factor: 3.85). 10/2008; 86(3):745-8. DOI: 10.1016/j.athoracsur.2008.05.039
Source: PubMed


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.
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.
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.
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.

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Available from: Georg Lutter, Aug 13, 2014
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    • "Further details have not yet been published. Simultaneously, our group has reported multiple studies, showing the feasibility of successful mitral valved stent implantation via transapical approach with follow up times of up to two months [7,8,9,10,11,12], in which a self-expanding valved stent was implanted in the native mitral position under transesophageal echocardiographic (TEE) guidance in the beating heart. The nitinol stent frame (Euroflex GmbH, Pforzheim, Germany), comprised of a ventricular stent body and an atrial element connected at a preset angle, was covered with a polytetrafluoroethylene (PTFE) membrane (Zeus Inc., Orangeburg, SC, USA) to minimize paravalvular leakage (PVL). "
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    ABSTRACT: The development of transcatheter techniques for treatment of severe mitral valve regurgitation in the beating heart is focus of recent research. An off-pump treatment technique poses great benefits, particularly for multimorbid patients, often being non-compliant to the gold standard treatment, being open heart surgery with use of a cardiopulmonary bypass. Thereto, two approaches are being followed: transcatheter valve repair and transcatheterimplantation of a valved stent into the native mitral valve annulus. A valved stent has to provide safe and secure fixation within the high pressure system of the left heart. One of the main challenges in the development of such a valved stent is the complex anatomy of the mitral valve, with no clearly defined structures for device anchorage. Our group has developed a self-expanding nitinolvalved stent for transapical implantation in the beating heart. During the development process of thevalved stent, different design iterations were conducted to decrease the risk of paravalvular leakages, to enhance the reproducibility and to improve the overall stent performance. This article reviews the major milestones passedin the development process of our mitral valved stent and advances achieved withinthe last years. Multiple design iterations lead to a prototype providing secure stent deployment, hig h reproducibility, low paravalvular leakages and only mild stent deformation in the beating heart. In future, further long-term in vivo trials have to be conducted before attempting the step towards clinical application of this novel device.
    Full-text · Article · Apr 2013
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    • "Thirdly, a delivery system must overcome obstacles posed by the mitral valve apparatus, which might impede perfect deployment. We recently published our initial experience with acute transapical off-pump mitral valved stent implantation with valved stents comprising a flat star-like disk and a tubular ventricular piece carrying different types of valves [3] [4]. These studies demonstrated the feasibility of transapical off-pump mitral valved stent implantation without LVOT obstruction. "
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    ABSTRACT: The present study investigates outcomes one month after implanting pigs with a novel mitral valved stent. A novel nitinol stent custom designed for this study included a bovine pericardial valve. Six pigs received a valved stent into the mitral position by means of the transapical implantation technique. Afterwards, haemodynamic stability and valve function were assessed, immediately after implantation (n = 6), 4 weeks (n = 4) and 8 weeks (n = 1) thereafter using transoesophageal echocardiography (TEE), ventriculography and cardiac computed tomography (CT). Four of 6 surviving pigs were sacrificed at 4 weeks after implantation and one at 8 weeks thereafter. Optimal deployment and positioning were obtained in all but one animal. This animal died of unrecognized imperfect valved stent positioning after 4 days. The average mean gradient across the new valves and the left ventricular outflow tract (LVOT) were small. Mild regurgitation developed after valved stent deployment in one of six animals just after 1 h, and in none thereafter. All animals exhibited normal haemodynamics after mitral valved stent implantation, and stability was maintained throughout the monitoring period. Migration, embolization and paravalvular leakage were not evident in the remaining animals after 4 and 8 weeks. Gross evaluation revealed that 50-70% of the atrial element was covered by tissue growth at 4 weeks/8 weeks. This study demonstrates adequate deployment and anchorage of a unique, repositionable mitral valved stent. A good valve function was revealed in animals observed for 4 weeks and in one pig after 8 weeks.
    Full-text · Article · Mar 2012 · European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery
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