Effect of low-dose positive inotropic drugs on human internal mammary artery flow.
BACKGROUND
Dobutamine (a beta-receptor agonist), enoximone (a type III selective phosphodiesterase inhibitor), and epinephrine (an alpha- and beta-mimetic) frequently are used in the perioperative management of patients undergoing coronary artery bypass grafting.


METHODS
We performed a double-blind clinical study to compare the effects on internal mammary artery free flow of low doses of these three positive inotropic drugs. Thirty patients in whom the left internal mammary artery was used for coronary artery bypass grafting were randomized into three groups. Internal mammary artery free flow and hemodynamic measurements were evaluated before and 10 minutes after the intravenous infusion of dobutamine (3 microg x kg(-1) x min(-1)), enoximone (200 microg/kg), or epinephrine (0.05 microg x kg(-1) x min(-1)).


RESULTS
A significant increase in free flow occurred only in the dobutamine group (33 +/- 7.5 and 42.2 +/- 7.9 mL/min before and after drug infusion, respectively; p = 0.013). Comparison of the increase in flow between the groups, however, showed no difference. These drugs, at doses designed to produce a positive inotropic effect, caused little increase in the free flow of the internal mammary artery.


CONCLUSIONS
The use of dobutamine, enoximone, and epinephrine as low-dose positive inotropic treatments in the perioperative and postoperative periods of coronary artery bypass grafting should depend on their positive inotropic effects rather than their vasodilative effects on the arterial grafts.
Cracowski
J L
JL
Department of Cardiac Surgery, Grenoble University Hospital, France.
Chavanon
O
O
Durand
M
M
Borrel
E
E
Devillier
P
P
Mallion
J M
JM
Blin
D
D
D000318:Adrenergic beta-Agonists / Q000008:administration & dosage; D000328:Adult; D000368:Aged; D002316:Cardiotonic Agents / Q000008:administration & dosage*; D001026:Coronary Artery Bypass; D003326:Coronary Circulation / Q000187:drug effects; D004280:Dobutamine / Q000008:administration & dosage; D004311:Double-Blind Method; D017335:Enoximone / Q000008:administration & dosage; D004837:Epinephrine / Q000008:administration & dosage; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008323:Mammary Arteries; D008875:Middle Aged; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage
D000318:Adrenergic beta-Agonists; D002316:Cardiotonic Agents; D010726:Phosphodiesterase Inhibitors; D004280:Dobutamine; D017335:Enoximone; D004837:Epinephrine