Coronary inflow and outflow responses to coronary artery occlusion.

Sudden complete occlusion of a major coronary artery (left circumflex or right coronary artery) was produced in anesthetized dogs. The effect on arterial inflow, venous outflow and O« saturation of coronary venous blood from the nonischemic left ventricle was studied. The usual response to occlusion of the left circumflex artery was an increase in flow in the left anterior descending artery and in outflow from the great cardiac vein. The O2 saturation of venous blood from the nonischemic muscle decreased. These changes did not occur following occlusion of the right coronary artery. It was not possible to measure tissue pressure accurately to relate this measurement to flow changes. Observations on coronary sinus flow and O2 saturation were also made following occlusion of the left circumflex artery and retrograde flow collection from it. These observations plus the changes in anterior descending inflow and great cardiac vein outflow with coronary occlusion suggest that these changes are more likely due to alterations in O2 consumption of the nonischemic muscle rather than to changes in flow through interarterial or non-interarterial collateral vessels. ADDITIONAL