Abstract This study is aimed to investigate the effects of different outlet boundary conditions and vessel wall thickness on time-averaged wall shear stress (TAWSS) and von Mises stress (VMS) in the coronary artery fluid structure interaction (FSI) analysis based on patient-specific computed tomography angiography(CTA)images. Firstly, 3D geometry of right coronary artery (RCA) lumen was reconstructed from CTA images. Then, lumen surface was expanded outward by 0.5 mm to establish uniform thickness vessel model. Finally, non-uniform thickness vessel was built by manually removing plaques. Zero and impedance boundary conditions were applied to the computational domains during FSI analysis. Distribution of TAWSS and VMS in a cardiac cycle from end diastolic phase were obtained and analyzed. TAWSS at stenosed sites were both significantly higher than other segments, and there was no significant difference with two outlet boundary conditions. Peak VMS appeared at 0.42 s (maximum pressure) with zero condition, while it appeared at 0.64 s (maximum flow velocity) with impedance condition and was 20 times higher. With impedance outlet boundary condition, the TAWSS in stenosed sites were both significantly higher than other segments, but had a similar distribution without statistical difference in different vessel models; the VMS distribution were both lower in stenosed sites and the absolute value of local VMS was higher in non-uniform thickness model than in uniform model. More accurate coronary structures and personalized flow and pressure boundary conditions were described based on the medical image, which is not only of great significance to studying relationship between hemodynamic, mechanical factors and cardiovascular disease, but also to serving patient-specific diagnosis and treatment.
Xu Chuangye,Liu Xiujian,Wu Guanghui, et al. Effects of Outlet Boundary Condition and Wall Thickness on Wall Shear Stress and von Mises Stress in Coronary Artery[J]. Chinese Journal of Biomedical Engineering, 2016, 35(4): 428-434.
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