Effect on coronary artery flow reserve and resistance in the remote area after acute coronary artery occlusion in the pig model.
BACKGROUND
It has been reported that vasodilator function in remote myocardial regions supplied by "angiographically normal" coronary arteries is impaired in patients after acute myocardial infarction (MI). The aim of this study was to determine whether coronary artery flow reserve and coronary artery resistance in remote, nonischemic areas are also altered in experimental MI.


METHODS
Experiments were performed in anesthetized pigs. In group 1 infarction was induced by ligation of the left-anterior descending artery (LAD); group 2 consisted of sham-operated animals. Hemodynamic parameters, coronary artery resistance, and myocardial blood flow (MBF) were measured before and 4 hours after MI under rest and during infusion of adenosine.


RESULTS
Coronary artery dilation by adenosine caused a similar increase in MBF before and 4 hours after coronary artery occlusion. Resting MBF after acute MI was not altered, although a significant reduction (15%; P < .04) in mean aortic pressure was observed compared with baseline. Coronary artery resistance was significantly reduced by adenosine (P < .04) before MI, as well as at 4 hours after MI (P < .03). Coronary artery flow reserve was not adversely affected. The sham-operated animals showed similar results without any significant differences between the two study groups.


CONCLUSIONS
This study indicates that an acute MI in pigs did not increase coronary artery resistance in the remote area after MI and therefore did not adversely affect coronary artery flow reserve in the nonischemic vascular bed. Further studies are necessary to fully understand the exact mechanism of the alterations in remote flow reserve of patients after MI.
Haas
F
F
Department of Cardiovascular Surgery, Deutsches Herzzentrum Muenchen, Germany.
Nguyen
N
N
Schad
H
H
Heimisch
W
W
Haehnel
C
C
Weigand
G
G
Ehrhard
W
W
Meisner
H
H
Schwaiger
M
M
D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D001011:Aorta; D001794:Blood Pressure; D003326:Coronary Circulation; D006339:Heart Rate; D009203:Myocardial Infarction / Q000503:physiopathology*; D013318:Stroke Volume; D013552:Swine; D014655:Vascular Resistance; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D000241:Adenosine