Stress-strain behavior of mitral valve leaflets in the beating ovine heart.
Stress-strain behavior of mitral valve leaflets in the beating ovine heart.
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DOI：
10.1016/j.jbiomech.2009.05.018
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发表时间：
2009-08-25
影响因子：
2.4
通讯作者：
Ingels, Neil B., Jr.
中科院分区：
文献类型：
--
作者：
Krishnamurthy, Gaurav;Itoh, Akinobu;Bothe, Wolfgang;Swanson, Julia C.;Kuhl, Ellen;Karlsson, Matts;Miller, D. Craig;Ingels, Neil B., Jr.
切除的二尖瓣前叶表现出各向异性、非线性材料行为，过渡前刚度范围为 0.06-0.09 N/mm2，过渡后刚度范围为 2-9 N/mm2。我们首次使用逆有限元 (FE) 分析来测试二尖瓣前叶 (AML) 在体内是否在等容舒张 (IVR) 期间表现出类似的非线性行为。将微型不透射线标记缝在 8 只绵羊的二尖瓣环、AML 和乳头肌上。在三个连续心动周期期间使用双平面视频荧光镜成像获得 4-D 标记坐标。 AML 的有限元模型是使用等容舒张结束时（当阀门上的压差大约为零时）的标记坐标作为参考状态来开发的。在 IVR 期间使用测量的左心室和心房压力来模拟 AML 位移。通过逆有限元分析获得每次心跳的径向和圆周方向的 AML 弹性模量，从而最大限度地减少模拟位移和测量位移之间的差异。每次心跳的应力-应变曲线是在 IVR 期间逐渐增加二尖瓣压力间隔时从 FE 模型获得的。 24 条单独的应力-应变曲线（8 颗心，每条心跳 3 次）的线性回归得出圆周方向的平均 (±SD) 线性相关系数 (r2) 为 0.994±0.003，径向为 0.995±0.003。因此，与孤立的小叶不同，AML在体内在关闭的二尖瓣的生理压力范围内线性运行。
Excised anterior mitral leaflets exhibit anisotropic, nonlinear material behavior with pre-transitional stiffness ranging from 0.06-0.09 N/mm2 and post-transitional stiffness from 2-9 N/mm2. We used inverse finite element (FE) analysis to test, for the first time, whether the anterior mitral leaflet (AML), in vivo, exhibits similar non-linear behavior during isovolumic relaxation (IVR). Miniature radiopaque markers were sewn to the mitral annulus, AML, and papillary muscles in 8 sheep. 4-D marker coordinates were obtained using biplane videofluoroscopic imaging during three consecutive cardiac cycles. A FE model of the AML was developed using marker coordinates at the end of isovolumic relaxation (when pressure difference across the valve is approximately zero), as the reference state. AML displacements were simulated during IVR using measured left ventricular and atrial pressures. AML elastic moduli in the radial and circumferential directions were obtained for each heartbeat by inverse FEA, minimizing the difference between simulated and measured displacements. Stress-strain curves for each beat were obtained from the FE model at incrementally-increasing transmitral pressure intervals during IVR. Linear regression of 24 individual stress-strain curves (8 hearts, 3 beats each) yielded a mean (±SD) linear correlation coefficient (r2) of 0.994±0.003 for the circumferential direction and 0.995±0.003 for the radial direction. Thus, unlike isolated leaflets, the AML, in vivo, operates linearly over a physiologic range of pressures in the closed mitral valve.
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影响因子：
2.1
作者：
Belegundu, AD;Damle, A;St Ville, J
通讯作者：
St Ville, J
DOI：
10.1098/rstb.2007.2123
发表时间：
2007-08-29
影响因子：
6.3
作者：
Kunzelman, K. S.;Einstein, D. R.;Cochran, R. P.
通讯作者：
Cochran, R. P.
影响因子：
37.8
作者：
LEVINE, RA;HANDSCHUMACHER, MD;WEYMAN, AE
通讯作者：
WEYMAN, AE
影响因子：
3.8
作者：
Chen, L;McCulloch, AD;May-Newman, K
通讯作者：
May-Newman, K
DOI：
10.1152/ajpheart.1995.269.4.h1319
发表时间：
1995-10-01
影响因子：
4.8
作者：
MAYNEWMAN, K;YIN, FCP
通讯作者：
YIN, FCP