Dobutamine versus dipyridamole for inducing reversible perfusion defects in chronic multivessel coronary artery stenosis.
OBJECTIVE
We hypothesized that, although the effects of dipyridamole and dobutamine on myocardial blood volume (MBV) and mean microbubble velocity (VEL) are different, the magnitude of perfusion deficit during both forms of stress is the same because both drugs unmask abnormal myocardial blood flow (MBF) reserve.


BACKGROUND
Both dipyridamole and dobutamine are used clinically as pharmacologic stress agents to induce reversible perfusion defects in patients with chronic coronary artery disease (CAD), but the basis for doing so for dobutamine is not clear.


METHODS
Eleven chronically instrumented closed-chest dogs with multivessel coronary stenosis were studied. Hemodynamics, radiolabeled microsphere-derived MBF, and myocardial contrast echocardiography (MCE)-derived myocardial perfusion were measured at rest, after dipyridamole infusion (0.56 mg x kg(-1)), and at peak dobutamine dose (either 30 or 40 microg x kg(-1) x min(-1)). Abnormal beds were defined as those demonstrating an MBF reserve <3 with dipyridamole.


RESULTS
In the presence of either drug, MBV increased more in the normal bed than in the abnormal bed, but the increase was higher in both beds with dobutamine than with dipyridamole. The slope of the relationship between MBF reserve and MBV reserve was greater during dobutamine than dipyridamole (p < 0.05). The converse was true for VEL reserve (p < 0.05). Consequently, the relationship between the ratios of either variable, or the product of the two, between the abnormal bed and normal bed was similar for both drugs.


CONCLUSIONS
Although the effects of dipyridamole and dobutamine on MBV and VEL are different, both are equally effective in detecting physiologically relevant coronary stenoses on MCE. Both can therefore be used interchangeably with myocardial perfusion imaging for the detection of CAD.
Bin
Jian-Ping
JP
Cardiovascular Imaging Center, the Cardiovascular Division, University of Virginia, Charlottesville, Virginia, USA.
Pelberg
Robert A
RA
Wei
Kevin
K
Le
D Elizabeth
DE
Goodman
N Craig
NC
Kaul
Sanjiv
S
D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D002316:Cardiotonic Agents / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D023921:Coronary Stenosis / Q000175:diagnosis / Q000503:physiopathology*; D004176:Dipyridamole / Q000494:pharmacology; D004280:Dobutamine / Q000494:pharmacology; D004285:Dogs; D004452:Echocardiography; D008863:Microspheres; D014665:Vasodilator Agents / Q000494:pharmacology
D002316:Cardiotonic Agents; D014665:Vasodilator Agents; D004280:Dobutamine; D004176:Dipyridamole