title: Hemodynamics of the string phenomenon in the internal thoracic artery grafted to the left anterior descending artery with moderate stenosis.
abstract: 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.
  
  
  
  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.
  
  
  
  A numerical study was performed by coupling the 3D artery model with 0-dimensional lumped parameter model of the cardiovascular system.
  
  
  
  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.
  
  
  
  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.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, PR China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhao
authors.affiliation: 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.
authors.forename: Youjun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, PR China.
authors.forename: Lanlan
authors.initials: L
authors.lastname: Li
authors.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, PR China.
authors.forename: Wenxin
authors.initials: W
authors.lastname: Wang
authors.affiliation: Beijing An Zhen Hospital affiliated to Capital Medical University, No. 2 Anzhen Road Chaoyang District, Beijing 100029, PR China.
authors.forename: Jinsheng
authors.initials: J
authors.lastname: Xie
authors.affiliation: Peking University People׳s Hospital, No. 11 Xizhimen South Street Xicheng District, Beijing 100044, PR China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Zhao
mesh_terms: D017023:Coronary Angiography; D001026:Coronary Artery Bypass; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D003331:Coronary Vessels / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008323:Mammary Arteries / Q000502:physiology*; D008875:Middle Aged; D066230:Patient-Specific Modeling; D011336:Probability; D013314:Stress, Mechanical
keywords: 0D/3D coupling simulation; Computational fluid dynamics (CFD); Coronary artery bypass grafting (CABG); Hemodynamics; Internal thoracic artery graft