AJP - Heart and Circulatory Physiology, Vol 259, Issue 3 706-H711, Copyright © 1990 by American Physiological Society
Functional anatomical site of intramural collaterals in dogs
K. W. Scheel, G. Daulat and S. E. Williams
Department of Physiology, Texas College of Osteopathic Medicine, Fort Worth 76107-2690.
The objectives of the present study were to determine quantitatively
whether the retrograde flow measurement reflects the total flow from
collateral vessels or overestimates or underestimates collateral flow, and
to determine the functional anatomical origin of intramural collaterals in
the native dog heart. In an isolated heart preparation, three experimental
procedures were used. 1) The left circumflex coronary artery was embolized
with microspheres of different sizes; then retrograde flows and the
peripheral coronary pressures were measured. 2) Epicardial collaterals were
cauterized, and retrograde flows were measured before and after cautery. 3)
Epicardial collaterals were cauterized followed by embolization of the
circumflex coronary artery with different size spheres. We found that 1)
the retrograde flow measurement underestimates the total collateral flow to
the circumflex coronary artery by approximately 25%, 2) intramural
collateral flow constitutes 58 +/- 3.5% of the retrograde flow measurement,
3) the antegrade component of blood flow that is not measured during a
retrograde flow measurement is from the intramural collateral circulation,
and 4) the functional site of origin of intramural collaterals is greater
than 25 microns but less than 80 microns in diameter. We conclude that, in
our preparation, retrograde flow underestimates total collateral flow, and
that intramural collateral flow is a major component of retrograde flow in
the native dog heart.
