The relationship between structural and hemodynamic heterogeneity
in microvascular networks.
Pries, A. R., T. W. Secomb, and P. Gaehtgens.
Dept. of Physiology, Freie Universit[umlaut]at Berlin, Arnimallee
22, D-14195 Berlin, Germany, Dept. of Physiology, University of
Arizona, Tucson, AZ 85724, USA
APStracts 2:0365H, 1995.
The relationship between structural and hemodynamic heterogeneity of
microvascular networks is examined by analyzing the effects of
topological and geometrical irregularities on network hemodynamics.
Microscopic observations of a network in the rat mesentery provided
data on length, diameter and interconnection of all segments (n =
913). Two idealized network structures were derived from the observed
network. In one, the topological structure was made symmetric, while
in another, a further idealization was made by assigning equal
lengths and diameters to all segments with topologically equivalent
positions in the network. Blood flow through these three networks was
simulated, using a mathematical model based on experimental
information on blood rheology. Overall network conductance and
pressure distribution within the network were found to depend
strongly on topological heterogeneity and less on geometric
heterogeneity. In contrast, mean capillary hematocrit was sensitive
to geometric heterogeneity, but not to topological heterogeneity.
Geometrical and topological heterogeneity contributed equally to the
dispersion of arterio-venous transit time. Hemodynamic
characteristics of heterogeneous microvascular networks can only be
adequately described if both topological and geometric variability in
network structure are taken into account.
Received 1 May 1995; accepted in final form 3 August 1995.
APS Manuscript Number H415-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 August 1995.