In Vivo Dynamic Deformation of the Mitral Valve Annulus
In Vivo Dynamic Deformation of the Mitral Valve Annulus
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DOI：
10.1007/s10439-009-9749-3
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发表时间：
2009-09-01
影响因子：
3.8
通讯作者：
Sacks, Michael S.
中科院分区：
文献类型：
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作者：
Eckert, Chad E.;Zubiate, Brett;Sacks, Michael S.
尽管二尖瓣 (MV) 修复手术在美国有所增加 [Gammie, J. S., et al.安.胸廓。外科医生。 87(5):1431-1437, 2009;诺维茨基，E.R.，等人。是。 Heart J. 145(6):1058-1062, 2003]，研究表明改变 MV 应激状态可能会对组织稳态产生影响，从而影响长期结果 [Accola, K. D., et al.安.胸廓。外科医生。 79(4):1276-1283, 2005;法索尔，R.，等人。安.胸廓。外科医生。 77（6）：1985-1988，2004；弗拉蒙，W.，P. Herijgers，和 K. Bogaerts。流通量 107(12):1609-1613, 2003;吉利诺夫，A.M.，等人。安.胸廓。外科医生。 69（3）：717-721，2000]。改进的计算模型结合了结构和几何数据以及细胞成分，有可能预测此类变化；然而，缺乏重要的边界条件信息限制了当前的努力。在这项研究中，从手术植入绵羊体内的声晶体中收集的新型高清体内环形运动学数据适合基于具有 C-2 连续性的五次阶 Hermite 形状函数的连续 3D 样条。根据插值位移，计算心动周期内的环轴向应变和应变率、沿整个环的弯曲和扭曲。轴向应变显示出区域和时间变化，观察到的最小值和最大值分别为 -10 % 和 4%。同样，观察到区域和时间上的应变率变化值，高达 100%/s 的收缩和 120%/s 的伸长。环形弯曲和扭曲数据都显示出与统一的偏差很小，区域变化有限，这表明大部分变形能量与环形轴向应变相关。环带的区域和时间变化应变/应变率行为与环带和周围心室结构的纤维肌结构和收缩行为的变化有关，尽管具体细节仍然不可用。利用本工作中描述的高分辨率形状和位移信息，可以在未来的 MV 有限元模型中规定高保真度边界条件，从而对 MV 功能和修复策略产生新的见解。
Though mitral valve (MV) repair surgical procedures have increased in the United States [Gammie, J. S., et al. Ann. Thorac. Surg. 87(5):1431-1437, 2009; Nowicki, E. R., et al. Am. Heart J. 145(6):1058-1062, 2003], studies suggest that altering MV stress states may have an effect on tissue homeostasis, which could impact the long-term outcome [Accola, K. D., et al. Ann. Thorac. Surg. 79(4):1276-1283, 2005; Fasol, R., et al. Ann. Thorac. Surg. 77(6):1985-1988, 2004; Flameng, W., P. Herijgers, and K. Bogaerts. Circulation 107(12):1609-1613, 2003; Gillinov, A. M., et al. Ann. Thorac. Surg. 69(3):717-721, 2000]. Improved computational modeling that incorporates structural and geometrical data as well as cellular components has the potential to predict such changes; however, the absence of important boundary condition information limits current efforts. In this study, novel high definition in vivo annular kinematic data collected from surgically implanted sonocrystals in sheep was fit to a contiguous 3D spline based on quintic-order hermite shape functions with C-2 continuity. From the interpolated displacements, the annular axial strain and strain rate, bending, and twist along the entire annulus were calculated over the cardiac cycle. Axial strain was shown to be regionally and temporally variant with minimum and maximum values of -10 and 4%, respectively, observed. Similarly, regionally and temporally variant strain rate values, up to 100%/s contraction and 120%/s elongation, were observed. Both annular bend and twist data showed little deviation from unity with limited regional variations, indicating that most of the energy for deformation was associated with annular axial strain. The regionally and temporally variant strain/strain rate behavior of the annulus are related to the varied fibrous-muscle structure and contractile behavior of the annulus and surrounding ventricular structures, although specific details are still unavailable. With the high resolution shape and displacement information described in this work, high fidelity boundary conditions can be prescribed in future MV finite element models, leading to new insights into MV function and strategies for repair.