Chordal force distribution determines systolic mitral leaflet configuration and severity of functional mitral regurgitation
Chordal force distribution determines systolic mitral leaflet configuration and severity of functional mitral regurgitation
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DOI：
10.1016/s0735-1097(98)00627-5
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发表时间：
1999-03-01
影响因子：
24
通讯作者：
Yoganathan, AP
中科院分区：
文献类型：
--
作者：
Nielsen, SL;Nygaard, H;Yoganathan, AP
本研究的目的是探讨腱索力分布对收缩期二尖瓣叶几何形状和二尖瓣功能的影响。这些之间的相互作用必须符合由跨瓣压差产生的弦合力（F-C）定义的弦力分布，其关闭瓣叶和腱索系留力（F-T）将瓣叶拉开。安装在左心室模型中，其中通过专用微型力传感器测量的前缘弦力通过改变左心室压力和乳头肌位置。通过二维超声心动图确定给定瓣叶构型覆盖瓣叶瓣口所需的腱索几何形状和闭塞瓣叶面积（奥拉），并进行三维重建。使用闭塞瓣叶面积表示瓣叶接合不完全。结果混合程序统计显示弦向净力之和、σ [F-C - F-T]（s）与奥拉（OLA）之间存在线性相关关系，回归系数为0.9999（最小值-最大值）β = -115至-65 [mm（2）/N]; p < 0.001和RF（β = -0.06至-0.01 [%N]; p < 0.001）。通过乳头肌对线不良增加FT限制了瓣叶活动性，由于接合线的顶端和后部移位导致了帐篷状瓣叶构型。前叶接合力增加，由于二尖瓣叶重塑，这产生了一个不均匀的adjuvantant orifice area.CONCLUSIONS改变弦力分布引起功能性二尖瓣反流的基础上，帐篷状瓣叶配置临床观察。(C)1999年由美国心脏病学会。
OBJECTIVES The purpose of this study was to investigate the impact of the chordae tendineae force distribution on systolic mitral leaflet geometry and mitral valve competence in vitro.BACKGROUND Functional mitral regurgitation is caused by changes in several elements of the valve apparatus. Interaction among these have to comply with the chordal force distribution defined by the chordal coapting forces (F-C) created by the transmitral pressure difference, which close the leaflets and the chordal tethering forces (F-T) pulling the leaflets apart.METHODS Porcine mitral valves (n = 5) were mounted in a left ventricular model where leading edge chordal forces measured by dedicated miniature force transducers were controlled by changing left ventricular pressure and papillry muscle position. Chordae geometry and occlusional leaflet area (OLA) needed to cover the leaflet orifice for a given leaflet configuration were determined by two-dimensional echo and reconstructed three-dimensionally. Occlusional leaflet area was used as expression for incomplete leaflet coaptation. Regurgitant fraction (RF) was measured with an electromagnetic flowmeter.RESULTS Mixed procedure statistics revealed a linear correlation between the sum of the chordal net forces, Sigma[F-C - F-T](s), and OLA with regression coefficient (minimum - maximum) beta = -115 to -65 [mm(2)/N]; p < 0.001 and RF (beta = -0.06 to -0.01 [%N]; p < 0.001). Increasing FT by papillary muscle malalignment restricted leaflet mobility, resulting in a tented leaflet configuration due to an apical and posterior shift of the coaptation line. Anterior leaflet coapting forces increased due to mitral leaflet remodeling, which generated a nonuniform regurgitant orifice area.CONCLUSIONS Altered chordal force distribution caused functional mitral regurgitation based on tented leaflet configuration as observed clinically. (C) 1999 by the American College of Cardiology.