Algabri Yousif A, Rookkapan Sorracha, Gramigna Vera, Espino Daniel M, Chatpun Surapong
Institute of Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, 6th floor, 100-year Building, Hatyai, Songkhla, 90110, Thailand.
Department of Radiology, Faculty of Medicine, Prince of Songkla University, Hatyai, Songkhla, 90110, Thailand.
Australas Phys Eng Sci Med. 2019 Mar;42(1):181-190. doi: 10.1007/s13246-019-00728-7. Epub 2019 Feb 14.
Aneurysms are considered as a critical cardiovascular disease worldwide when they rupture. The clinical understanding of geometrical impact on the flow behaviour and biomechanics of abdominal aortic aneurysm (AAA) is progressively developing. Proximal neck angulations of AAAs are believed to influence the hemodynamic changes and wall shear stress (WSS) within AAAs. Our aim was to perform pulsatile simulations using computational fluid dynamics (CFD) for patient-specific geometry to investigate the influence of severe angular (≥ 60°) neck on AAA's hemodynamic and wall shear stress. The patient's geometrical characteristics were obtained from a computed tomography images database of AAA patients. The AAA geometry was reconstructed using Mimics software. In computational method, blood was assumed Newtonian fluid and an inlet varying velocity waveform in a cardiac cycle was assigned. The CFD study was performed with ANSYS software. The results of flow behaviours indicated that the blood flow through severe bending of angular neck leads to high turbulence and asymmetry of flows within the aneurysm sac resulting in blood recirculation. The high wall shear stress (WSS) occurred near the AAA neck and on surface of aneurysm sac. This study explained and showed flow behaviours and WSS progression within high angular neck AAA and risk prediction of abdominal aorta rupture. We expect that the visualization of blood flow and hemodynamic changes resulted from CFD simulation could be as an extra tool to assist clinicians during a decision making when estimation the risks of interventional procedures.
动脉瘤破裂时被视为全球范围内一种严重的心血管疾病。对腹主动脉瘤（AAA）血流行为和生物力学的几何影响的临床认识正在逐步发展。人们认为AAA的近端颈部角度会影响AAA内的血流动力学变化和壁面剪应力（WSS）。我们的目的是使用计算流体动力学（CFD）针对患者特定几何形状进行脉动模拟，以研究严重角度（≥60°）颈部对AAA血流动力学和壁面剪应力的影响。患者的几何特征来自AAA患者的计算机断层扫描图像数据库。使用Mimics软件重建AAA几何形状。在计算方法中，血液被假定为牛顿流体，并指定了心动周期内入口处变化的速度波形。使用ANSYS软件进行CFD研究。流动行为结果表明，通过角度颈部严重弯曲的血流会导致高湍流以及瘤腔内血流不对称，从而导致血液再循环。高壁面剪应力（WSS）出现在AAA颈部附近和瘤腔表面。本研究解释并展示了高角度颈部AAA内的流动行为和WSS进展以及腹主动脉破裂的风险预测。我们期望CFD模拟产生的血流可视化和血流动力学变化可以作为一种额外工具，在评估介入手术风险时协助临床医生进行决策。
