title: Bioinspired helical graft with taper to enhance helical flow.
abstract: Helical flow has been introduced to improve the hemodynamic performance of vascular devices such as arterial grafts, stents and arteriovenous shunts to overcome the flow induced thrombus formation and intimal hyperplasia. However, the quite low intensity of helical flow in the existing devices may limit their function. To obtain desirably high intensity, inspired by the helical flow and tapered configuration of the arterial system, we proposed a new conceptual design of the medical devices, which take the form of a tapered helical shape. We demonstrated its effectiveness in arterial grafts by numerically comparing the hemodynamic performance of helical grafts with different smooth tapers. The results show that the helicity density quantifying the helical flow enlarges sharply with the increase of the taper under both steady and pulsatile flow conditions. Moreover, the amplified helical flow induced by the taper would lead to highly elevated wall shear stress, remarkably reduced oscillating shear index and relative residence time at both the grafts and the anastomosis of the host vessel. The present findings therefore indicated that the new helical graft with taper would significantly enhance the helical flow in the grafts and host vessel, which may reduce the possibility of thrombus formation in the graft and intimal hyperplasia in the host vessel and hence improve the graft patency. In addition, the concept of helical shape with taper may also be applied to design arterial stents and arteriovenous shunts to obtain better hemodynamic performance.
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
authors.forename: Libing
authors.initials: L
authors.lastname: Wang
authors.affiliation: National Research Center for Rehabilitation Technical Aids, Beijing, China.
authors.forename: Zhenze
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
authors.forename: Zhengxing
authors.initials: Z
authors.lastname: Li
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Kang
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China; National Research Center for Rehabilitation Technical Aids, Beijing, China.
authors.forename: Yubo
authors.initials: Y
authors.lastname: Fan
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China. Electronic address: saq@buaa.edu.cn.
authors.forename: Anqiang
authors.initials: A
authors.lastname: Sun
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China. Electronic address: dengxy1953@buaa.edu.cn.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Deng
mesh_terms: D001807:Blood Vessel Prosthesis; D006439:Hemodynamics; D019737:Transplants
keywords: Graft; Helical flow; Intimal hyperplasia; Taper; Thrombosis