Civil and Industrial Engineering Department, University of Pisa, Largo Lucio Lazzarino, 2, 56122, Pisa, Italy.
BioCardioLab, Bioengineering Unit, Heart Hospital, Fondazione CNR - Regione Toscana G. Monasterio, Via Aurelia Sud, 54100, Massa, Italy.
Cardiovasc Eng Technol. 2023 Oct;14(5):713-725. doi: 10.1007/s13239-023-00682-2. Epub 2023 Sep 19.
The impact of the distribution in space of the inlet velocity in the numerical simulations of the hemodynamics in the thoracic aorta is systematically investigated. A real healthy aorta geometry, for which in-vivo measurements are available, is considered. The distribution is modeled through a truncated cone shape, which is a suitable approximation of the real one downstream of a trileaflet aortic valve during the systolic part of the cardiac cycle. The ratio between the upper and the lower base of the truncated cone and the position of the center of the upper base are selected as uncertain parameters. A stochastic approach is chosen, based on the generalized Polynomial Chaos expansion, to obtain accurate response surfaces of the quantities of interest in the parameter space. The selected parameters influence the velocity distribution in the ascending aorta. Consequently, effects on the wall shear stress are observed, confirming the need to use patient-specific inlet conditions if interested in the hemodynamics of this region. The surface base ratio is globally the most important parameter. Conversely, the impact on the velocity and wall shear stress in the aortic arch and descending aorta is almost negligible.
系统研究了在胸主动脉血液动力学数值模拟中入口速度空间分布对计算结果的影响。研究采用了真实健康的升主动脉几何形状，其体内测量值是可用的。采用截断圆锥形状对分布进行建模，这是心脏周期收缩部分三尖瓣主动脉瓣下游真实分布的合适近似。选择截断圆锥的上下底面的比例以及上底面中心的位置作为不确定参数。选择基于广义多项式混沌展开的随机方法，以获得感兴趣参数空间中的数量的精确响应面。选定的参数会影响升主动脉中的速度分布。因此，观察到壁面切应力的影响，这证实如果对该区域的血液动力学感兴趣，那么需要使用患者特定的入口条件。底面比是全局最重要的参数。相反，对主动脉弓和降主动脉中的速度和壁面切应力的影响几乎可以忽略不计。
