Microvascular blood volume-to-flow relationships in porcine heart
wall - in vivo evaluation with whole-body ct.
Liu, Yun-He, Robert C. Bahn, and Erik L. Ritman, (with The Technical
Assistance Of Patricia E. Beighley).
Hypertension and Vascular Research Division, Henry Ford Hospital,
Detroit, MI 48202, Department of Medical Pathology, and Department of
Physiology and Biophysics, Mayo Clinic, Rochester, MN 55905
APStracts 2:0199H, 1995.
The goal of this study was to evaluate the functional behavior of
recruitable (mostly capillary) and of non recruitable (mostly
arterioles, venules, etc.) components of the intramyocardial
microvasculature in the in situ heart of intact experimental animals.
For this purpose fast x-ray CT scans were performed in a group of
anesthetized pigs. Each scan was performed during an aortic root
angiogram and was repeated after sequential injections of a
suspension of nonradioactive microspheres into a selected coronary
artery. Regional myocardial perfusion (F, mL x g-1 x min-1) and
intramyocardial blood volume (_, mL x g-1) were estimated from the
dynamic CT image sequences. For the intramyocardial microcircula tion
_=AF+BF 1/2 (where A=0.016 min and B=0.076 [ml x g-1 x min] 1/2 ) was
shown to describe the _ to F relationship over the entire range of
flows observed. With increasing embolization with 15_m diameter
microspheres, the coefficients, A and B, changed in a way consis tent
with A describing the transit time through the functionally
recruitable component and B/F 1/2 the transit time through the
functionally non recruitable component of the microcirculation.
Received 14 November 1994; accepted in final form 10 May 1995.
APS Manuscript Number H1011-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 26 May 1995.