Computational fluid dynamics of a vascular access case for hemodialysis
Computational fluid dynamics of a vascular access case for hemodialysis
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DOI：
10.1115/1.1372702
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发表时间：
2001-06-01
影响因子：
1.7
通讯作者：
Remuzzi, A
中科院分区：
文献类型：
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作者：
Ene-Iordache, B;Mosconi, L;Remuzzi, A
血液透析的血管通路（VA）通常由自体动静脉内瘘（AVF）或合成移植物创建。维持VA通畅仍然是终末期肾病患者的主要问题，因为在这些血管中经常发生血栓形成和内膜增生。这些病变通常与在分叉处或急剧弯曲处附近发展的扰动流有关。我们探讨了使用计算流体动力学（CFD）在患者特定的端到端自体AVF模型中研究血流动力学的可能性。使用数字减影血管造影的动静脉瘘，我们产生了一个三维网格的血流数值分析。作为输入条件，在桡动脉的时间依赖性的血液波形来自于在回声彩色多普勒超声检查期间获得的中心线速度。使用流体动力学软件包计算有限元解。在桡动脉的直的传入侧，壁剪切应力范围在20和36达因/厘米（2）之间。在静脉侧，吻合口近端，壁面剪应力在负值和正值之间振荡（从-12 dynes/cm（2）到112 dynes/cm（2）），而吻合口远端，壁面剪应力恢复到生理范围内，范围从8到22 dynes/cm（2）。动静脉分流后，在桡动脉弯曲区和静脉侧发现了具有非常高剪切应力梯度的血管壁区域。在这些区域也观察到次级血流。CFD给出了血流场的详细描述，并表明该方法可用于针对患者的血管分析，以更好地了解局部血流动力学条件在血管病变发展中的作用。
Vascular accesses (VA) for hemodialysis are usually created by native arteriovenous fistulas (AVF) or synthetic grafts. Maintaining patency of VA continues to be a major problem for patients with end-stage renal disease, since in these vessels thrombosis and intimal hyperplasia often occur. These lesions are frequently associated with disturbed flow that develops near bifurcations or sharp curvatures. We explored the possibility of investigating blood flow dynamics in a patient-specific model of end-to-end native AVF using computational fluid dynamics (CFD). Using digital subtraction angiographies of an AVF, we generated a three-dimensional meshwork for numerical analysis of blood flow. As input condition, a time-dependent blood waveform in the radial artery was derived from centerline velocity obtained during echo-color-Doppler ultrasound examination. The finite element solution was calculated using a fluid-dynamic software package. In the straight, afferent side of the radial artery wall shear stress ranged between 20 and 36 dynes/cm(2). On the venous side, proximal to the anastomosis, wall shear stress was oscillating between negative and positive values (from -12 dynes/cm(2) to 112 dynes/cm(2)), while distal from the anastomosis, the wall shear stress returned within the physiologic range, ranging from 8 to 22 dynes/cm(2). Areas of the vessel wall with very high shear stress gradient were identified on the bending zone of the radial artery and on the venous side, after the arteriovenous shunt. Secondary blood flows were also observed in these regions. CFD gave a detailed description of blood flow field and showed that this approach can be used for patient-specific analysis of blood vessels, to understand better the role of local hemodynamic conditions in the development of vascular lesions.