Late coronary artery reperfusion has additive beneficial effects on infarct expansion when combined with early angiotensin converting enzyme inhibitor therapy post myocardial infarction.
BACKGROUND
Individually, late coronary artery reperfusion and early angiotensin converting enzyme (ACE) inhibitor therapy prevent infarct expansion post myocardial infarction (MI).


OBJECTIVE
To examine the effect of late reperfusion on infarct expansion when added to early ACE inhibitor therapy post MI.


METHODS
Rats were randomized into two groups: Reperfusion group: rats underwent coronary artery occlusion followed by reperfusion 2 hours after MI, a time too late to reduce infarct size. A control group: rats underwent permanent coronary artery occlusion followed by a sham operation 2 hours after MI. All rats received enalapril (2.0 +/- 0.2 mg/kg) daily in drinking water, started immediately after the second operation. Rats were sacrificed 2 weeks after coronary occlusion. Hearts were arrested and fixed at a constant pressure, then sectioned and photographed for morphometric analysis.


RESULTS
Infarct size was similar in the reperfusion and control groups (23 +/- 2 vs 26 +/- 2%, p = NS). Septal thickness was also similar in both groups (1.8 +/- 0.1 vs 1.8 +/- 0.1 mm, p = NS). There was a trend towards thicker infarcts in the reperfusion group compared to the control group (0.84 +/- 0.06 vs 0.72 +/- 0.05 mm, p = 0.1). Compared to early ACE inhibition alone, late reperfusion combined with early ACE inhibition limited infarct expansion (expansion index, 1.13 +/- 0.12 vs 1.44 +/- 0.14, p < 0.05), prevented left ventricular (LV) dilation (LV volume, 0.30 +/- 0.02 vs 0.39 +/- 0.03 ml, p < 0.01) and prevented LV hypertrophy (LV weight, 0.71 +/- 0.18 vs 0.77 +/- 0.20 gm, p < 0.05).


CONCLUSIONS
Late coronary artery reperfusion prevents infarct expansion, LV dilation and hypertrophy even when added to early ACE inhibitor therapy post MI. This suggests that late reperfusion may be beneficial in patients with acute MI treated with early ACE inhibitor therapy.
Duchatellier
T
T
Department of Medicine, Bronx Lebanon Hospital Center, Albert Einstein College of Medicine, NY 10457, USA.
Brown
E J
EJ
Alhaddad
I A
IA
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000818:Animals; D003131:Combined Modality Therapy; D004656:Enalapril / Q000627:therapeutic use; D005260:Female; D006352:Heart Ventricles / Q000473:pathology; D017379:Hypertrophy, Left Ventricular / Q000473:pathology; D009203:Myocardial Infarction / Q000188:drug therapy / Q000473:pathology / Q000628:therapy*; D015425:Myocardial Reperfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D016707:Tissue Fixation
D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril