Decreased reactive hyperemia after coronary perfusion with nonoxygenated solution

To gain more knowledge about the factors involved in reactive hyperemia in the coronary vessels, we performed comparative studies on the reactive hyperemia occurring after coronary occlusion and after coronary perfusion with nonoxygenated Tyrode solution. The peak coronary reactive hyperemic flow following 3 min of coronary perfusion with nonoxygenated Tyrode solution increased to only 142 +/- 16% of the control in contrast to 455 +/- 75% following 3 min of coronary occlusion alone. Myocardial oxygen uptake during reactive hyperemia was also much smaller after perfusion with Tyrode solution. First, the evidence suggests that the decreased reactive hyperemia after coronary perfusion with the nonoxygenated Tyrode solution is due to "washout" of the vasodilatory metabolites from the myocardium. Second, it suggests that there is a smaller "energy debt" during perfusion with Tyrode solution, so that deterioration of myocardial function due to oxygen deficiency is less severe than in coronary occlusion alone.