Evaluation of intramyocardial coronary blood flow waveform during intraaortic balloon pumping in the absence or presence of coronary stenosis.

Our aim was to evaluate the effects of intraaortic balloon pumping (IABP) on the blood velocity waveform in the absence or presence of coronary artery stenosis. Using anesthetized open-chest dogs, the septal arterial blood flow velocities were measured with a 20 MHz 80-channel ultrasound pulsed Doppler velocimeter in the absence (n = 5) or presence (n = 3) of left main coronary artery stenosis. The blood velocity waveform was analyzed by calculating the systolic retrograde velocity integral (SR) and the diastolic antegrade velocity integral (DA). A slosh ratio was defined as SR/DA. The left anterior descending arterial flow (CBF), aortic pressure (AoP), and poststenotic distal coronary pressure (DiP) were also measured simultaneously. We compared the effect of IABP on the velocity waveforms in the absence and in the presence of coronary artery stenosis. In the absence of stenosis, IABP increased DiP during diastole and augmented DA while it also increased SR. IABP augmented the net CBF because of the greater increase in DA than SR. In the presence of stenosis, however, IABP did not increase DiP and resulted in no significant effect on the net CBF.