Murphy Jonathan B, Boyle Fergal J
Department of Mechanical Engineering, Dublin Institute of Technology, Dublin, Ireland.
Biorheology. 2010;47(2):117-32. doi: 10.3233/BIR-2010-0568.
The benefit of coronary stent implantation is reduced by excessive intimal hyperplasia which re-narrows the artery and the prevention of which is still a primary concern for clinicians. Abnormal hemodynamics create non-physiological viscous stress on the artery wall, one of the root causes of intimal hyperplasia following stent implantation. A methodology to comprehensively evaluate the viscous stress on the artery wall following stent implantation would be useful to evaluate a stent's hemodynamic performance.The proposed methodology employs 3D computational fluid dynamics, the variables wall shear stress (WSS), WSS gradient (WSSG), WSS angle gradient (WSSAG) and a statistical analysis to evaluate the viscous stress. The methodology is demonstrated and compared to a commonly used "threshold technique" for evaluating a stent's hemodynamic performance.It is demonstrated that the threshold technique is not adequate to fully analyse the viscous stress on the artery wall and can even be misleading. Furthermore, all three of the aforementioned variables should be considered as each provides a different perspective on the abnormalities that can arise in the arterial viscous stress.The hemodynamic performance of a stent can be assessed more comprehensively than with previously used methods by examining the arterial viscous stresses using the proposed methodology.
过度的内膜增生会使冠状动脉支架植入的益处降低,内膜增生会使动脉再次狭窄,而预防内膜增生仍是临床医生的主要关注点。异常的血流动力学在动脉壁上产生非生理性粘性应力,这是支架植入后内膜增生的根本原因之一。一种全面评估支架植入后动脉壁粘性应力的方法,将有助于评估支架的血流动力学性能。所提出的方法采用三维计算流体动力学、壁面切应力(WSS)、WSS梯度(WSSG)、WSS角度梯度(WSSAG)等变量以及统计分析来评估粘性应力。该方法得到了验证,并与一种常用的评估支架血流动力学性能的“阈值技术”进行了比较。结果表明,阈值技术不足以全面分析动脉壁上的粘性应力,甚至可能产生误导。此外,上述三个变量都应予以考虑,因为每个变量都能从不同角度反映动脉粘性应力可能出现的异常情况。通过使用所提出的方法检查动脉粘性应力,可以比以前使用的方法更全面地评估支架的血流动力学性能。