Method for assessing the need for case-specific hemodynamics: Application to the distribution of vascular permeability

A common approach to understanding the role of hemodynamics in atherogenesi s is to seek relationships between parameters of the hemodynamic environmen t, and the distribution of tissue variables thought to be indicative of ear ly disease. An important question arising in such investigations is whether the distributions of tissue variables are sufficiently similar among cases to permit them to be described by an ensemble average distribution. If the y are, the hemodynamic environment needs be determined only once, for a nom inal representative geometry; if not, the hemodynamic environment must be o btained for each case. A method for classifying distributions from multiple cases to answer this question is proposed and applied to the distributions of the uptake of Evens blue dye labeled albumin by the external iliac arte ries of swine in response to a step increase in how. It is found that the u ptake patterns in the proximal segment of the arteries, between the aortic trifurcation and the ostium of the circumflex iliac artery, show considerab le case-to-case variability. In the distal segment, extending to the deep f emoral ostium, many cases show very little spatial variation. and the patte rns in those that do are similar among the cases. Thus the response of the distal segment may be understood with fewer simulations, but the proximal s egment has more information to offer. (C) 2000 Biomedical Engineering Socie ty. [S0090-6964(00)00711-6].