Effects of chronic anemia on the coronary and coronary collateral vasculature in dogs.
We compared coronary resistances and collateral (retrograde) flows for a group of normal dogs (hematocrit 40) to values for a group of dogs with severe chronic anemia (hematocrit 17). We used an isolated heart preparation in which the vessels were maximally dilated by dipyridamole. All data were compared for a hematocrit of 40. The results showed a significant decrease in coronary resistances with anemia; average resistances (+/-SE) of the anterior descending, circumflex, and right coronary arteries of the control dogs were 1.04 +/- 0.09,0.74 +/- 0.01, and 2.63 +/- 0.17 mm Hg/[(ml/min)/100 g], respectively, and 0.6 +/- 0.04,0.41 +/- 0.05,and 1.17 +/- 0.15 for the anemic dogs. Average coronary collateral flows increased in anemia but statistical significance could not be shown. We conclude that increased vascularity is a long-term regulatory mechanism in response to a hypoxic stimulus.
D000740:Anemia / Q000503:physiopathology*; D000818:Animals; D001783:Blood Flow Velocity; D002908:Chronic Disease; D003097:Collateral Circulation / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects; D004176:Dipyridamole / Q000494:pharmacology; D004285:Dogs; D006400:Hematocrit; D008297:Male; D010477:Perfusion / Q000379:methods; D013997:Time Factors; D014655:Vascular Resistance
D004176:Dipyridamole