Myocardial reactive hyperemia caused by initial myocardial anoxia during aortic valve replacement

Reactive hyperemic response of individual coronary arteries and of the whole heart to anoxia during coronary cannulation was investigated in 10 patients undergoing aortic valve replacement. Reactive hyperemic response in man is identical to that reported in experimental investigations. The duration of hyperemic response was dependent on the length of the preceding period of anoxia; the longer the period of anoxia, the more prolonged was the hyperemic response. No significant collateral circulation between the coronary arteries could be demonstrated during prolonged anoxia of an individual coronary artery. Blood flow debt was almost always overpaid, but the repayment percentage decreased with the lengthening of the anoxic period, being 460 percent after a short period of anoxia (less than or equal to 2 minutes), 230 percent after an anoxic period of moderate length (3 to 5 minutes), and only 160 percent after a long period of anoxia (greater than or equal to 7 minutes). The total mean repayment of blood flow debt of the whole heart was 195 percent.