A Longitudinal Study of Remodeling in a Revised Peripheral Artery Bypass Graft Using 3D Ultrasound Imaging and Computational Hemodynamics
A Longitudinal Study of Remodeling in a Revised Peripheral Artery Bypass Graft Using 3D Ultrasound Imaging and Computational Hemodynamics
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DOI：
10.1115/1.4003622
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发表时间：
2011-04-01
影响因子：
1.7
通讯作者：
Aliseda, Alberto
中科院分区：
文献类型：
--
作者：
McGah, Patrick M.;Leotta, Daniel F.;Aliseda, Alberto
我们报告了血液动力学切应力在外周动脉搭桥移植物重塑和失败中的作用。在移植物翻修后的16个月时间里，对股骨至月国窝膝上搭桥移植物进行了三次单独的扫描。根据定制的3D超声系统获得的数据重建管腔的形态。数值模拟是用患者特定的几何形状和生理上真实的流速进行的。超声重建显示了两个重要的重塑区域：面积缩小超过85%的狭窄，最终导致移植物失败，以及狭窄后管腔扩张或扩大。同样，模拟显示了移植物内复杂的血液动力学环境。与活体测速仪的初步比较也表明，与模拟中观察到的流动动力学定性一致。两种不同的流动特征被识别出来，并被假设为直接启动了观察到的活体重建。首先，在狭窄处发生了流动分离。随后狭窄远端形成低切变率的回流区。低剪切区被认为有利于平滑肌细胞的增殖和内膜的生长。狭窄后的射流从狭窄处喷出，随后撞击管腔壁。管腔膨胀被认为是与射流撞击相关的高剪应力和高频压力波动的直接结果。[DOI：10.1115/1.4003622]
We report a study of the role of hemodynamic shear stress in the remodeling and failure of a peripheral artery bypass graft. Three separate scans of a femoral to popliteal above-knee bypass graft were taken over the course of a 16 month period following a revision of the graft. The morphology of the lumen is reconstructed from data obtained by a custom 3D ultrasound system. Numerical simulations are performed with the patient-specific geometries and physiologically realistic flow rates. The ultrasound reconstructions reveal two significant areas of remodeling: a stenosis with over 85% reduction in area, which ultimately caused graft failure, and a poststenotic dilatation or widening of the lumen. Likewise, the simulations reveal a complicated hemodynamic environment within the graft. Preliminary comparisons with in vivo velocimetry also showed qualitative agreement with the flow dynamics observed in the simulations. Two distinct flow features are discerned and are hypothesized to directly initiate the observed in vivo remodeling. First, a flow separation occurs at the stenosis. A low shear recirculation region subsequently develops distal to the stenosis. The low shear region is thought to be conducive to smooth muscle cell proliferation and intimal growth. A poststenotic jet issues from the stenosis and subsequently impinges onto the lumen wall. The lumen dilation is thought to be a direct result of the high shear stress and high frequency pressure fluctuations associated with the jet impingement. [DOI: 10.1115/1.4003622]