Bapat Vinnie, Pirone Francesco, Kapetanakis Stam, Rajani Ronak, Niederer Steven
Department of Cardiothoracic Surgery and Cardiology, Guy's and St. Thomas' Hospital, London, United Kingdom.
Department of Biomedical Engineering, Kings College, London, United Kingdom.
Catheter Cardiovasc Interv. 2015 Oct;86(4):747-60. doi: 10.1002/ccd.25928.
To determine the factors influencing left ventricular outflow tract (LVOT) area reduction after a mitral valve-in-valve (VIV) or a valve-in-ring (VIR) procedure.
Transcatheter heart valves (THVs) are increasingly used in performing a VIV or a VIR procedure in high-risk patients. Although less invasive, a potential complication is LVOT obstruction. However, the factors predisposing to LVOT obstruction are ill defined.
To understand the effects of the various factors, the study was carried out in three parts: To understand the effect of VIV and VIR on reduction in LVOT area with special attention to different surgical heart valve (SHV) orientations and depth of THV implant. This was carried out in porcine and cadaver hearts. To quantify aorto-mitral-annular (AMA) angle in 20 patients with or without mitral disease and to derive a static computational model to predict LVOT obstruction. To study the effect of SHV design on LVOT obstruction after VIV. This was carried out as a bench test. LVOT area reduction was similar after VIV irrespective of orientation of the mitral SHV implantation as it pinned open the SHV leaflets. Similar effect was seen after VIR. The degree of LVOT obstruction was partly determined by AMAangle and was inversely proportional. SHV design, ring design, and depth of SPAIEN XT implantation also had effect on LVOT obstruction.
A possibility of LVOT obstruction should be considered when performing a VIV and VIR procedure. Type of SHV, flexible ring, less obtuse AMA angle, and depth of SAPIEN XT implant can influence the risk.
确定影响二尖瓣瓣中瓣（VIV）或瓣中环（VIR）手术后左心室流出道（LVOT）面积减小的因素。
经导管心脏瓣膜（THV）越来越多地用于高危患者的VIV或VIR手术。尽管侵入性较小，但一个潜在的并发症是LVOT梗阻。然而，导致LVOT梗阻的因素尚不明确。
为了解各种因素的影响，本研究分三个部分进行：了解VIV和VIR对LVOT面积减小的影响，特别关注不同的外科心脏瓣膜（SHV）方向和THV植入深度。这在猪心脏和尸体心脏中进行。量化20例有或无二尖瓣疾病患者的主动脉-二尖瓣环（AMA）角度，并推导一个静态计算模型来预测LVOT梗阻。研究SHV设计对VIV后LVOT梗阻的影响。这作为一个台架试验进行。无论二尖瓣SHV植入的方向如何，VIV后LVOT面积减小情况相似，因为它使SHV瓣叶张开。VIR后也观察到类似效果。LVOT梗阻的程度部分由AMA角度决定，且呈反比关系。SHV设计、环设计和SPAIEN XT植入深度也对LVOT梗阻有影响。
在进行VIV和VIR手术时应考虑LVOT梗阻的可能性。SHV类型、柔性环、较小的钝角AMA角度和SAPIEN XT植入深度会影响风险。
