Author + information
- Received June 2, 1995
- Revision received October 26, 1995
- Accepted November 10, 1995
- Published online March 15, 1996.
- Akihiro Kimura, MD, PhD,
- Eiji Toyota, MD∗,
- Lu Songfang, BS,
- Masami Goto, MD, PhD,
- Toyotaka Yada, MD, PhD,
- Yoko Chiba, MD,
- Jun Ebata, MD,
- Hiroyuki Tachibana, CE,
- Yasuo Ogasawa, PhD,
- Katsuhiko Tsujioka, MD, PhD and
- Fumihiko Kajiya, MD, PhD
- ↵∗Address for correspondence: Dr. Eiji Toyota, Department of Medical Engineering and Systems Cardiology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-01, Japan.
Objectives. 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 to 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.
☆ This study was supported by Grant-in-Aid 00671366 for General Scientific Research (C) for 1994 from the Ministry of Education, Science, and Culture, Tokyo, Japan.
- Received June 2, 1995.
- Revision received October 26, 1995.
- Accepted November 10, 1995.