title: Comparison between experimentally measured flow patterns for straight and helical type graft.
abstract: The long-term success of arterial bypass surgery is often limited by the progression of intimal hyperplasia at the anastomosis between the graft and the native artery. The experimental models were manufactured from glass tubing with constant internal diameter of 8 mm, fashioned into a straight configuration and helical configuration. The aim of this study was to determine the three-dimensional flow structures that occur at the proximal anastomosis under pulsatile flow conditions, to investigate the changes that resulted from variations in the anastomosis angle and flow division, and to establishing the major differences between the straight and helical graft. In the anastomosis domain, a strong region of recirculation is observed near the occluded end of the artery, which forces the flow to move into the perfused host coronary artery. The proximal portion of the host tube shows weak counter-rotating vortices on the symmetry plane. The exact locations and strengths of the vortices in this region are only weakly dependent on Re. A detailed comparison of experimentally measured axial velocity patterns for straight and helical grafts confirm the very strong nature of the secondary flows in the helical geometry. The helical configuration promotes the mixing effect of vortex motion such that the flow particles are mixed into the blood stream disal to the anastomotic junction.
authors.affiliation: Romanian Academy - Timisoara Branch, Centre for Fundamental and Advanced Technical Research, Bd. Mihai Viteazul 24, RO-300223, Timisoara, Romania.
authors.forename: Sandor I
authors.initials: SI
authors.lastname: Bernad
authors.forename: Alin
authors.initials: A
authors.lastname: Bosioc
authors.forename: Elena S
authors.initials: ES
authors.lastname: Bernad
authors.forename: Marius L
authors.initials: ML
authors.lastname: Craina
mesh_terms: D000714:Anastomosis, Surgical / Q000379:methods*; D001777:Blood Coagulation; D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis; D003198:Computer Simulation; D001026:Coronary Artery Bypass / Q000379:methods*; D003331:Coronary Vessels / Q000473:pathology / Q000601:surgery; D004867:Equipment Design; D005898:Glass; D006439:Hemodynamics; D006801:Humans; D057446:Hydrodynamics; D008955:Models, Cardiovascular; D011673:Pulsatile Flow; D012212:Rheology; D033081:Shear Strength; D017539:Tunica Intima / Q000473:pathology; D058017:Vascular Grafting / Q000379:methods
keywords: Bypass graft; anastomosis; helical graft; hemodynamics