Modelling secondary lymphatic valves with a flexible vessel wall: how geometry and material properties combine to provide function.
Modelling secondary lymphatic valves with a flexible vessel wall: how geometry and material properties combine to provide function.
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DOI：
10.1007/s10237-020-01325-4
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发表时间：
2020-12
影响因子：
3.5
通讯作者：
Bertram CD
中科院分区：
文献类型：
--
作者：
Bertram CD
建立了血管内淋巴阀的三维流体/结构相互作用有限元模型，分别模拟了阀开、关两种压力差下淋巴阀的特性。血管壁和瓣叶的新胡克材料的剪切模量不同，瓣在静止状态下的开度也不同。还研究了事先对整个阀门进行压力充气对阀门特性的影响。这些特性由通过阀的体积流量、流体阻力、最大窦半径和叶尖间隙在等分叶叶的对称平面上进行参数化，所有这些都是施加压力差的函数。在瓣段两端施加的压力增大时，瓣叶二分平面上的最大窦半径增大，但也反映了瓣叶引起的窦截面非圆形变形，使得瓣叶在有利压差较小的情况下通过极小值。当壁面较硬时，瓣开时叶间间隙显著增大；当它像小叶一样柔韧时，间隙增加得更线性。当壁或叶材料更灵活时，打开和关闭阀门所需的压力差更小。阀门特性对开启位置的偏置程度随着静息位置叶间间隙和阀门充气压力的增大而增大。将模拟阀的特性与现有的一个或多个收集淋巴管的集总参数模型中指定的特性进行比较，并用于估计该模型中控制阀开/关速率随施加压差变化的常数的修正值。评价修正值对集总参数模型预测的淋巴泵送效果的影响。
A three-dimensional finite-element fluid/structure-interaction model of an intravascular lymphatic valve was constructed, and its properties investigated under both favourable and adverse pressure differences, simulating valve opening and valve closure respectively. The shear modulus of the neo-Hookean material of both vascular wall and valve leaflet was varied, as was the degree of valve opening at rest. Also investigated was how the valve characteristics were affected by prior application of pressure inflating the whole valve. The characteristics were parameterised by the volume flow-rate through the valve, the hydraulic resistance to flow, and the maximum sinus radius and inter-leaflet-tip gap on the plane of symmetry bisecting the leaflet, all as functions of the applied pressure difference. Maximum sinus radius on the leaflet-bisection plane increased with increasing pressure applied to either end of the valve segment, but also reflected the non-circular deformation of the sinus cross-section caused by the leaflet, such that it passed through a minimum at small favourable pressure differences. When the wall was stiff, the inter-leaflet gap increased sigmoidally during valve opening; when it was as flexible as the leaflet, the gap increased more linearly. Less pressure difference was required both to open and to close the valve when either the wall or the leaflet material was more flexible. The degree of bias of the valve characteristics to the open position increased with both the inter-leaflet gap in the resting position and valve inflation pressure. The characteristics of the simulated valve were compared with those specified in an existing lumped-parameter model of one or more collecting lymphangions, and used to estimate a revised value for the constant in that model which controls the rate of valve opening/closure with variation in applied pressure difference. The effects of the revised value on the lymph pumping efficacy predicted by the lumped-parameter model were evaluated.
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DOI：
10.1115/1.4023986
发表时间：
2013-05-01
影响因子：
1.7
作者：
Wilson, John T.;Wang, Wei;Moore, James E., Jr.
通讯作者：
Moore, James E., Jr.
影响因子：
3.5
作者：
Ballard, Matthew;Wolf, Ki T.;Alexeev, Alexander
通讯作者：
Alexeev, Alexander
影响因子：
4.6
作者：
Li, Huabing;Mei, Yumeng;Munn, Lance L.
通讯作者：
Munn, Lance L.
影响因子：
2.4
作者：
Phillips, MN;Jones, GT;Zhang, M
通讯作者：
Zhang, M
影响因子：
2.4
作者：
Dixon, J. Brandon;Greiner, Steven T.;Zawieja, David C.
通讯作者：
Zawieja, David C.