Improvement of myocardial blood flow to ischemic regions by angiotensin-converting enzyme inhibition with quinaprilat IV: a study using [15O] water dobutamine stress positron emission tomography.
OBJECTIVE
This study was designed to analyze the effects of acute angiotensin-converting enzyme (ACE) inhibition on myocardial blood flow (MBF) in control and ischemic regions.


BACKGROUND
Although animal studies indicate an improvement of MBF to ischemic regions after ACE inhibition, this effect has not been conclusively demonstrated in patients with coronary artery disease.


METHODS
Myocardial blood flow was analyzed in ischemic and nonischemic regions of 10 symptomatic patients with coronary artery disease using repetitive [15O] water positron emission tomography at rest and during maximal dobutamine stress before and after ACE inhibition with quinaprilat 10 mg i.v. To exclude the possibility that repetitive ischemia may cause an increase in MBF, eight patients underwent the same protocol without quinaprilat (placebo patients).


RESULTS
Rate pressure product in control and quinaprilat patients was comparable. In placebo patients, repetitive dobutamine stress did not change MBF to ischemic regions (1.41 +/- 0.17 during the first stress vs. 1.39 +/- 0.19 ml/min/g during the second stress, p = 0.93). In contrast, MBF in ischemic regions increased significantly after acute ACE inhibition with quinaprilat during repetitive dobutamine stress (1.10 +/- 0.13 vs. 1.69 +/- 0.17 ml/min/g, p < 0.015). Dobutamine coronary reserve in ischemic regions remained unchanged in placebo patients (1.07 +/- 0.11 vs. 1.10 +/- 0.16, p = 0.92), but increased significantly after quinaprilat (0.97 +/- 0.10 vs. 1.44 +/- 0.14, p < 0.002). Total coronary resistance decreased after ACE inhibition (123 +/- 19 vs. 71 +/- 10 mm Hg x min x g/ml, p < 0.02).


CONCLUSIONS
Angiotensin-converting enzyme inhibition by quinaprilat significantly improves MBF to ischemic regions in patients with coronary artery disease.
Schneider
C A
CA
Klinik III für Innere Medizin, Universität zu Köln, Germany. christian.schneider@medizin.uni-koeln.de
Voth
E
E
Moka
D
D
Baer
F M
FM
Melin
J
J
Bol
A
A
Wagner
R
R
Schicha
H
H
Erdmann
E
E
Sechtem
U
U
D000328:Adult; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D002316:Cardiotonic Agents; D003326:Coronary Circulation / Q000187:drug effects*; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000188:drug therapy*; D004280:Dobutamine; D005080:Exercise Test; D005260:Female; D006801:Humans; D007546:Isoquinolines / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D044005:Tetrahydroisoquinolines; D014055:Tomography, Emission-Computed; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000187:drug effects
D000806:Angiotensin-Converting Enzyme Inhibitors; D002316:Cardiotonic Agents; D007546:Isoquinolines; D044005:Tetrahydroisoquinolines; C054501:quinaprilat; D004280:Dobutamine