[Assessment of the effects of dipyridamole and dobutamine on coronary microcirculation using myocardial contrast echocardiography].
OBJECTIVE
To evaluate the effects of dipyridamole and dobutamine on myocardial blood flow (MBF) and myocardial blood volume (MBV), and their ability to detect non-flow-limiting coronary stenoses with myocardial contrast echocardiography (MCE).


METHODS
Thirteen closed-chest dogs were studied at 7-10 days after placement of ameroid constrictors around proximal coronary arteries and their branches. MBF was measured with radiolabeled microspheres and myocardial plateau video intensity (VI, which indicates relative MBV) and microbubble velocity (beta) were measured with MCE at rest, after dipyridamole (0.56 mg/kg), and during peak dobutamine dose (30-40 micrograms.kg-1.min-1).


RESULTS
The effects of both agents on MBF were similar in abnormal and normal segments. Plateau VI increased more and beta increased less with dobutamine than dipyridamole (P < 0.05), but the plateau VI ratios and beta ratios between abnormal and normal segments were almost identical during both drugs (P < NS), resulting in similar perfusion defects. Excellent linear relations were found between the plateau VI ratio or beta ratio and MBF (derived from radiolabeled microspheres) ratio from abnormal and normal beds during dipyridamole and dobutamine.


CONCLUSIONS
Although the effect of dipyridamole and dobutamine on MBV is different, they unmask MBF reserve to a similar extent. Thus, the quantification of stenosis severity is identical using both agents with MCE.
Bin
J
J
Cardiovascular Division, Nanfang Hospital, First Military Medical University, Guangzhou 510515, China.
Wei
K
K
Pelberg
R A
RA
D000818:Animals; D001783:Blood Flow Velocity; D001810:Blood Volume; D003326:Coronary Circulation / Q000187:drug effects*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D004176:Dipyridamole / Q000494:pharmacology*; D004195:Disease Models, Animal; D004280:Dobutamine / Q000494:pharmacology*; D004285:Dogs; D004452:Echocardiography; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D004280:Dobutamine; D004176:Dipyridamole