title: Fluid-dynamic optimal design of helical vascular graft for stenotic disturbed flow.
abstract: Although a helical configuration of a prosthetic vascular graft appears to be clinically beneficial in suppressing thrombosis and intimal hyperplasia, an optimization of a helical design has yet to be achieved because of the lack of a detailed understanding on hemodynamic features in helical grafts and their fluid dynamic influences. In the present study, the swirling flow in a helical graft was hypothesized to have beneficial influences on a disturbed flow structure such as stenotic flow. The characteristics of swirling flows generated by helical tubes with various helical pitches and curvatures were investigated to prove the hypothesis. The fluid dynamic influences of these helical tubes on stenotic flow were quantitatively analysed by using a particle image velocimetry technique. Results showed that the swirling intensity and helicity of the swirling flow have a linear relation with a modified Germano number (Gn*) of the helical pipe. In addition, the swirling flow generated a beneficial flow structure at the stenosis by reducing the size of the recirculation flow under steady and pulsatile flow conditions. Therefore, the beneficial effects of a helical graft on the flow field can be estimated by using the magnitude of Gn*. Finally, an optimized helical design with a maximum Gn* was suggested for the future design of a vascular graft.
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea.
authors.forename: Hojin
authors.initials: H
authors.lastname: Ha
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea.
authors.forename: Dongha
authors.initials: D
authors.lastname: Hwang
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea.
authors.forename: Woo-Rak
authors.initials: WR
authors.lastname: Choi
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea.
authors.forename: Jehyun
authors.initials: J
authors.lastname: Baek
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea; Center for Biofluid and Biomimic Research, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea.
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D001157:Arterial Occlusive Diseases / Q000503:physiopathology*; D001808:Blood Vessels / Q000503:physiopathology*; D004867:Equipment Design; D057446:Hydrodynamics; D011673:Pulsatile Flow; D012039:Regional Blood Flow; D058017:Vascular Grafting