Effect of aortic insufficiency on arterial blood pressure, coronary blood flow and cardiac oxygen consumption.

In patients with aortic insufficiency and without disease of the coronary ostia or arteries, the occurrence of chest pain having some or many of the characteristics of cardiac pain due to myocardial ischemia has been ascribed classically to a decrease in the coronary blood flow (1, 2), the aortic insufficiency presumably decreasing the coronary blood flow by lowering the mean aortic diastolic pressure. However, the data available on the effect of aortic insufficiency on the coronary blood flow are contradictory. From acute experiments on the anesthestized dog, Green (3), as well as Green and Gregg (4), concluded that when the aortic insufficiency is marked enough to lower the aortic diastolic pressure, the increase in coronary blood flow occurring during systole does not compensate for the decrease in flow during diastole and the mean coronary flow decreases. On the other hand, Foltz, Wendel, and West (5), from measurements made on anesthetized dogs in which one or two aortic cusps had been torn three or more days previously, concluded that the coronary blood flow was increased over levels usually observed in normal dogs while oxygen consumption was greatly increased over normal levels. Because of the discrepancy in the opinions about the effect of aortic insufficiency on the coronary blood flow, it was thought advisable to reinvestigate this problem.