Effect of coronary sinus occlusion on coronary pressure-flow relations
Bellamy, R.F.; Lowensohn, H.S.; Ehrlich, W.; Baer, R.W.
American Journal of Physiology 239(1): H57-H64
1980
ISSN/ISBN: 0002-9513 PMID: 7396018 Document Number: 163085
We studied the effect of transient occlusion of the coronary sinus on the relationship between aortic pressure and circumflex coronary blood flow in open-chest anesthetized dog preparations during artificially prolonged diastoles. The coronary pressure-flow relation was linear, and flow stopped at an arterial pressure (Pf = 0) that always exceeded coronary venous pressure (Pcv). During reactive hyperemia, Pf = 0 was 31 mmHg when Pcv was 5 mmHg and increased to 52 mmHg when the coronary sinus was occluded (Pcv, 38 mmHg). Elevation of Pcv translated the coronary pressure-flow relation to a higher Pf = 0 without altering the slope of the relation. Pf = 0 increased by about two-thirds of the increase in Pcv. We found no evidence that there existed a level of Pcv below which changes in Pcv had no effect on the coronary pressure-flow relation. These data are not compatible with the existence of a vascular waterfall mechanism in the coronary circulation unless it is assumed that Pcv is one of the determinants of Pf = 0.