Effects of intraaortic balloon pumping on septal arterial blood flow velocity waveform during severe left main coronary artery stenosis.
OBJECTIVE
We sought to evaluate the effect of intraaortic balloon pumping on the phasic blood velocity waveform into myocardium with severe coronary artery stenosis.


BACKGROUND
In the presence of severe coronary artery stenosis, it is not clear whether intraaortic balloon pumping augments intramyocardial inflow during diastole or changes systolic retrograde blood flow from the myocardium to the extramural coronary arteries.


METHODS
Using anesthetized open chest dogs (n=7), we introduced severe stenosis in the left main coronary artery to reduce the poststenotic pressure to approximately 60 mm Hg (>90% diameter stenosis). Septal arterial blood flow velocities were measured with a 20-MHz, 80-channel ultrasound pulsed Doppler velocimeter. Left anterior descending arterial flow, aortic pressure and poststenotic distal coronary pressure were measured simultaneously. The diastolic anterograde flow integral and systolic retrograde flow integral were compared in the presence and absence of intraaortic balloon pumping.


RESULTS
Although intraaortic balloon pumping augmented diastolic aortic pressure, this pressure increase was not effectively transmitted through stenosis. Septal arterial diastolic flow velocity was not augmented, and left anterior descending arterial flow was unchanged during intraaortic balloon pumping.


CONCLUSIONS
In the presence of severe coronary artery stenosis, intraaortic balloon pumping failed to increase diastolic inflow in the myocardium and did not enhance systolic retrograde flow from the myocardium to the extramural coronary artery. Thus, the major effect of intraaortic balloon pumping on the ischemic heart with severe coronary artery stenosis may be achieved by reducing oxygen demand by systolic unloading.
Kimura
A
A
Department of Medical Engineering and Systems Cardiology, Kawasaki Medical School, Okayama, Japan.
Toyota
E
E
Lu
S
S
Goto
M
M
Yada
T
T
Chiba
Y
Y
Ebata
J
J
Tachibana
H
H
Ogasawara
Y
Y
Tsujioka
K
K
Kajiya
F
F
D000704:Analysis of Variance; D000818:Animals; D001158:Arteries; D001783:Blood Flow Velocity; D003251:Constriction, Pathologic / Q000000981:diagnostic imaging / Q000503:physiopathology; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003971:Diastole; D004285:Dogs; D005260:Female; D006439:Hemodynamics; D007423:Intra-Aortic Balloon Pumping; D008297:Male; D013599:Systole; D018617:Ultrasonography, Doppler, Pulsed