title: Effect of compliance and hematocrit on wall shear stress in a model of the entire coronary arterial tree.
abstract: A hemodynamic analysis is implemented in the entire coronary arterial tree of diastolically arrested, vasodilated pig heart that takes into account vessel compliance and blood viscosity in each vessel of a large-scale simulation involving millions of vessels. The feed hematocrit (Hct) is varied at the inlet of the coronary arterial tree, and the Fahraeus-Lindqvist effect and phase separation are considered throughout the vasculature. The major findings are as follows: 1) vessel compliance is the major determinant of nonlinearity of the pressure-flow relation, and 2) changes in Hct influence wall shear stress (WSS) in epicardial coronary arteries more significantly than in transmural and perfusion arterioles because of the Fahraeus-Lindqvist effect. The present study predicts the flow rate as a second-order polynomial function of inlet pressure due to vessel compliance. WSS in epicardial coronary arteries increases >15% with an increase of feed Hct from 45% to 60% and decreases >15% with a decrease of feed Hct from 45% to 30%, whereas WSS in small arterioles is not affected as feed Hct changes in this range. These findings have important implications for acute Hct changes under vasodilated conditions.
authors.affiliation: Department of Biomedical Engineering, Surgery, and Cellular and Integrative Physiology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Huo
authors.forename: Ghassan S
authors.initials: GS
authors.lastname: Kassab
mesh_terms: D000818:Animals; D001160:Arterioles / Q000502:physiology; D001794:Blood Pressure; D001809:Blood Viscosity; D003187:Compliance; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000033:anatomy & histology / Q000502:physiology*; D006400:Hematocrit; D008833:Microcirculation; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D017711:Nonlinear Dynamics; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013552:Swine; D014664:Vasodilation