Xi Zhao1, Youjun Liu2, Lanlan Li1, Wenxin Wang1, Jinsheng Xie3, Zhou Zhao4. 1. College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, PR China. 2. College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, PR China. Electronic address: lyjlma@bjut.edu.cn. 3. Beijing An Zhen Hospital affiliated to Capital Medical University, No. 2 Anzhen Road Chaoyang District, Beijing 100029, PR China. 4. Peking University People׳s Hospital, No. 11 Xizhimen South Street Xicheng District, Beijing 100044, PR China.
Abstract
PURPOSE: The internal thoracic artery is the choice of graft for coronary artery bypass grafting due to the excellent long-term patency. However internal thoracic artery graft failures still occur due to diffuse narrowing, known as the string phenomenon. Studies suggest that the string phenomenon is caused by competitive flow when the coronary stenosis is not serious, but the hemodynamics of the string phenomenon are still unclear. The purpose of this study is to clarify the hemodynamic characteristics of the string phenomenon. MATERIALS: A patient-specific 3-dimensional model of the aortic arch and coronary arteries was reconstructed. A moderate stenosis was applied to the left anterior descending artery. The internal thoracic artery was used to bypass the stenosis. Two further 3D models were built to study the hemodynamics of the string phenomenon. METHODS: A numerical study was performed by coupling the 3D artery model with 0-dimensional lumped parameter model of the cardiovascular system. RESULTS: The graft flow, native coronary flow, wall shear stress and oscillatory shear index were calculated and illustrated. Inverse flow and high oscillatory shear index appeared on the internal thoracic artery graft when the stenosis was moderate. CONCLUSION: High oscillatory shear index might be the major hemodynamic characteristic of the string phenomenon in internal thoracic artery graft. The inverse graft flow and the difference in graft flow caused by clamping the stenosis can be used to evaluate the probability of observing the string phenomenon.
PURPOSE: The internal thoracic artery is the choice of graft for coronary artery bypass grafting due to the excellent long-term patency. However internal thoracic artery graft failures still occur due to diffuse narrowing, known as the string phenomenon. Studies suggest that the string phenomenon is caused by competitive flow when the coronary stenosis is not serious, but the hemodynamics of the string phenomenon are still unclear. The purpose of this study is to clarify the hemodynamic characteristics of the string phenomenon. MATERIALS: A patient-specific 3-dimensional model of the aortic arch and coronary arteries was reconstructed. A moderate stenosis was applied to the left anterior descending artery. The internal thoracic artery was used to bypass the stenosis. Two further 3D models were built to study the hemodynamics of the string phenomenon. METHODS: A numerical study was performed by coupling the 3D artery model with 0-dimensional lumped parameter model of the cardiovascular system. RESULTS: The graft flow, native coronary flow, wall shear stress and oscillatory shear index were calculated and illustrated. Inverse flow and high oscillatory shear index appeared on the internal thoracic artery graft when the stenosis was moderate. CONCLUSION: High oscillatory shear index might be the major hemodynamic characteristic of the string phenomenon in internal thoracic artery graft. The inverse graft flow and the difference in graft flow caused by clamping the stenosis can be used to evaluate the probability of observing the string phenomenon.
Authors: Bao Li; Ke Xu; Jincheng Liu; Boyan Mao; Na Li; Hao Sun; Zhe Zhang; Xi Zhao; Haisheng Yang; Liyuan Zhang; Tianming Du; Jianhang Du; Youjun Liu Journal: Front Physiol Date: 2021-04-12 Impact factor: 4.566
Authors: Muhammad Owais Khan; Justin S Tran; Han Zhu; Jack Boyd; René R Sevag Packard; Ronald P Karlsberg; Andrew M Kahn; Alison L Marsden Journal: J Cardiovasc Transl Res Date: 2020-04-02 Impact factor: 3.216