AJP - Heart and Circulatory Physiology, Vol 253, Issue 5 1279-H1288, Copyright © 1987 by American Physiological Society
Development of coronary collateral circulation in left circumflex Ameroid-occluded swine myocardium
D. M. Roth, Y. Maruoka, J. Rogers, F. C. White, J. C. Longhurst and C. M. Bloor
Department of Pathology, School of Medicine, University of California, San Diego, La Jolla 92093.
Coronary collateral development was examined in 34 pigs after gradual
occlusion of the left circumflex coronary artery (LCX) with an Ameroid
constrictor. Collateral development was assessed by measurements of
myocardial blood flow and regional myocardial function at rest and during
exercise over a 16-wk period after placement of the constrictor. Coronary
collateral development was adequate to prevent severe infarction and
restore blood flow to the collateral-dependent LCX region within 3-7 wk.
Infarction averaged 5.0 +/- 1.3% of the LCX region. Blood flows at rest
were 1.05 +/- 0.14 and 1.13 +/- 0.15 ml.min-1.g-1 in the subendocardium of
the collateral and control regions, respectively, 7 wk postoperatively.
Concurrently, collateral vessel development supported normal myocardial
function at rest as determined by systolic wall thickening in the LCX
region. However, collateral development was limited, since blood flows
during moderate and severe exercise were reduced in the LCX region compared
with control and left anterior descending and right coronary regions. Blood
flow ratios (collateral/control flow) during severe exercise 3 wk
postoperatively were 0.23 +/- 0.03 and 0.57 +/- 0.05 in the subendocardium
and subepicardium and were constant throughout the 16-wk period throughout
the study. Myocardial function of the collateral region also was reduced
during exercise and a 30-min recovery period. We suggest that this limited
coronary collateral circulation, which develops in response to gradual
coronary occlusion in swine, serves as a model for the human collateral
circulation for the study of protocols to alter growth and development of
coronary collateral vessels.
