A technique to assess aortic distensibility and compliance in
anesthetized and awake rats.
Gorp, Ad Van, Dorette S. Van Ingen Schenau, Jean Willigers, Arnold P.
G. Hoeks, Jo G. R. De Mey, Harry A. J. Struyker Boudier, and Robert
S. Reneman.
Departments of Physiology, Pharmacology and Biophysics,
Cardiovascular Research Institute Maastricht, University of Limburg,
Maastricht, the Netherlands
APStracts 2:0517H, 1995.
A non-invasive ultrasonic technique, based upon tracking arterial wall
displa cements with a vessel wall tracking device attached to a
conventional B-mode imager, to assess end-diastolic aortic diameter
(d) and aortic diameter changes during the cardiac cycle ([delta]d)
in anesthetized and awake rats is presented. From these parameters
and invasively measured aortic pulse pressure ([delta]P), aortic
distensibility and compliance, the relative and absolute increase in
lumen cross-sectional area for a given increase in [delta]P,
respectively, can be calculated. d, [delta]d and [delta]P could be
determined with good intra-session (variations per day) and inter
-session (variations between days) coefficients of variation (CV). The
CV's for [delta]d were smaller in awake (4.6-6.0%) than in
anesthetized rats (7.9-11.0%), probably due to variations in [delta]P
during anesthesia (CV's: 9.0-12.3%). The CV's for d in awake (3.3
-6.5%) and anesthetized rats (2.6-5.0%) were comparable. In awake rats
the CV for [delta]d, but not for d, increased after implantation of
the aortic catheter. It is concluded that d, [delta]d and [delta]P of
the aorta can be reliably measured non-invasively in anesthetized and
awake rats, allowing the in vivo assessment of aortic distensibility
and compliance. The technique is sensitive enough to detect effects
of agents on aortic wall properties.
Received 10 April 1995; accepted in final form 3 August 1995.
APS Manuscript Number H349-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95