Simultaneous Measurement of Total and Nutritional Coronary Blood Flow in Dogs
Significant correlation has been shown between the severity of coronary disease and level of coronary blood flow as measured by the rubidium coincidence technique. Contrary to the commonly expressed view, however, the rubidium coincidence method does not evaluate nutritional flow, but estimates total coronary blood flow (CBFT). An equation is derived that does evaluate nutritional flow (CBFN), allowing simultaneous measurement of total and nutritional flow.
The extraction ratio of the total body (ERTB) relative to the extraction ratio of the heart (ERC) was measured in a total of 21 dogs by employing the relative uptake of labeled microspheres and diffusible ions, 86Rb and 131Cs.
CBFT, measured with a bolus injection of 86Rb or 131Cs, was compared with total flow measured by the microsphere technique in dogs, with and without drug administration (norepinephrine, isoproterenol, nitroglycerin). These studies showed that while rubidium gives accurate mean values of total flow (4% mean difference, r = 0.92) individual estimates may be in error by as much as ± 42%. It was found, however, that isotopes of cesium are not suitable for measuring either total or nutritional coronary blood flow by the methods described in this paper.
Comparison of CBFN with CBFT showed that not only was CBFN significantly less than CBFT, but the percentage increase in CBFN was significantly less than that of CBFT after norepinephrine or isoproterenol administration.
- Radioactive microspheres
- Extraction ratios
- Received May 15, 1973.
- Accepted September 24, 1973.
- © 1974 American Heart Association, Inc.