Spatial comparison between wall shear stress measures and porcine arterial endothelial permeability

1 Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708; and 2 Biomedical Engineering Center, The Ohio State University, Columbus, Ohio 43210 Submitted 18 September 2003 ; accepted in final form 29 December 2003 A better understanding of how hemodynamic factors affect the integrity and function of the vascular endothelium is necessary to appreciate more fully how atherosclerosis is initiated and promoted. A novel technique is presented to assess the relation between fluid dynamic variables and the permeability of the endothelium to macromolecules. Fully anesthetized, domestic swine were intravenously injected with the albumin marker Evans blue dye, which was allowed to circulate for 90 min. After the animals were euthanized, silicone casts were made of the abdominal aorta and its iliac branches. Pulsatile flow calculations were subsequently made in computational regions derived from the casts. The distribution of the calculated time-dependent wall shear stress in the external iliac branches was directly compared on a point-by-point basis with the spatially varying in vivo uptake of Evans blue dye in the same arteries. The results indicate that in vivo endothelial permeability to albumin decreases with increasing time-average shear stress over the normal range. Additionally, endothelial permeability increases slightly with oscillatory shear index. computational fluid dynamics; in vivo measurement; oscillatory shear index; albumin; Evans blue dye Address for reprint requests and other correspondence: M. H. Friedman, Dept. of Biomedical Engineering, Duke Univ., PO Box 90281, Durham, NC 27708 (E-mail: mhfriedm{at}duke.edu ).