Effect of initial myocardial anoxia on coronary flow during aortic valve replacement

Flow to the right and left coronary arteries was recorded continuously during aortic valve replacement using continous constant-pressure coronary perfusion at 32 degrees C in 13 patients. The initially high coronary flow decreased gradually until a certain level, the so-called resting flow level, was reached and stabilized there as long as perfusion temperature remained unchanged. At 32 degrees C, resting flow was about 50% of the peak hyperaemic flow. The length of preceding anoxia had a significant effect on the duration of reactive hyperaemic response. After a short anoxic period, resting flow level was reached in about 3 min, after moderate period in 15 min and after long anoxia in 35 min, respectively.