AJP - Heart and Circulatory Physiology, Vol 242, Issue 1 94-H97, Copyright © 1982 by American Physiological Society
Importance of injection site for coronary blood flow determinations by microspheres in rats
P. Wicker and R. C. Tarazi
Because coronary blood flow (CBF) determinations require that blood and
microspheres be uniformly mixed in the root of the aorta, we developed a
technique of left-atrial (LA) catheterization in rats and compared the
variability of results obtained by LA injection and left-ventricular (LV)
injection as regards systemic [cardiac output (CO)], proximal (coronary),
and distal (renal, cerebral) flows in anesthetized animals. CBF values
averaged 410 +/- 224 and 358 +/- 99 (SD) ml.min-1.100 g-1 from LV and LA
injection, respectively, or 5.7 +/- 2.9 and 4.9 +/- 1.3 (SD) %CO. The
variability with LA injection was significantly lower than with LV
injection as shown by the marked differences in standard deviations
obtained with the two methods (224 vs. 99 ml.min-1.100 g-1 or 2.9 vs. 1.3
%CO, P greater than 0.01). In contrast, no significant difference in
variability was found for either CO or more distal regional flows. These
results indicate that LV injections might be adequate for systemic flow and
regional flows to relatively distal beds but that accurate measurements of
CBF require LA injection of microspheres.
