AJP - Heart and Circulatory Physiology, Vol 250, Issue 2 181-H188, Copyright © 1986 by American Physiological Society
Noninvasive measurements of nonlinear arterial elasticity
J. Megerman, J. E. Hasson, D. F. Warnock, G. J. L'Italien and W. M. Abbott
To describe fully the compliance characteristics of an artery with
nonlinear elastic properties, measurements must be obtained over a wide
range of pressures. Furthermore, repeated measurements, as required in
temporal studies of arterial implants, require that the measuring technique
be noninvasive. The application of a pulsed ultrasound echo-tracking device
is described, which fulfills both criteria. Nonlinear compliance-pressure
(CP) curves were obtained from the femoral arteries of dogs, with the use
of halothane anesthesia to vary systemic pressure, and were used to compare
the gross elastic properties of different vessels. Studies using controlled
hemorrhage or the vasoactive drugs, nitroprusside and levarterenol
(norepinephrine), were used to verify that the CP curves obtained during
halothane anesthesia did not reflect varying degrees of smooth muscle
activation. However, surgical exposure did temporarily reduce arterial
compliance at pressures between 60 and 140 mmHg. The effect of vasoactive
intervention and of postsurgical changes in arterial or graft compliance
can thus be quantitated by use of CP curves or by comparing incremental
elastic moduli, which can also be estimated from the noninvasively derived
measurements.
