Time dependence of left ventricular recovery after delayed recanalization of an occluded infarct-related coronary artery: findings of a pilot study.
OBJECTIVE
We sought to test the hypothesis that late recanalization of infarct-related coronary arteries (IRAs) improves long-term left ventricular (LV) function.


BACKGROUND
Reperfusion within 24 h of an acute myocardial infarction (MI) has been shown to improve myocardial healing and to reduce infarct expansion. Uncontrolled data suggest that there may be a time window of several weeks for such an effect.


METHODS
Sixteen asymptomatic patients 10 +/- 4 days after a first Q wave anterior wall MI with persistent left anterior descending coronary artery occlusion and infarct-zone akinesia were randomized to immediate (2 weeks) or delayed (3 months) angioplasty. Repeat catheterization and cardiac magnetic resonance imaging (MRI) were performed after 3 and 12 months.


RESULTS
Angiography 3 months after MI revealed that LV ejection fraction (LVEF) had increased ([mean +/- SD] 54.4 +/- 4.3% vs. 63.9 +/- 7.4%, p < 0.01) as a result of improved regional function (p < 0.01) and LV end-systolic volume had decreased (p < 0.002), whereas LV end-diastolic volume remained unchanged. With delayed angioplasty, LVEF, infarct zone wall motion and LV volumes did not improve. Cardiac MRI at baseline and at 3 and 12 months confirmed these findings and extended them up to 1 year, indicating that delayed angioplasty could no longer improve LV function because of marked LV dilation (p < 0.01). Immediate angioplasty had a high success rate, but restenosis (50%) was accompanied by new severe angina as a clinical indicator of salvaged myocardium, which did not occur after delayed angioplasty.


CONCLUSIONS
This pilot study in selected patients supports the hypothesis that myocardial viability persists ("hibernation") for 2 to 3 weeks but not for 3 months after MI, during which time it may be worthwhile to restore blood flow to a large myocardial territory, even in asymptomatic patients, to improve long-term LV function.
Department of Internal Medicine, University Hospital, Basel, Switzerland. pfisterer@email.ch
M E
ME
Pfisterer
P
P
Buser
S
S
Osswald
P
P
Weiss
J
J
Bremerich
F
F
Burkart
D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization; D003326:Coronary Circulation / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology / Q000628:therapy*; D015428:Myocardial Reperfusion Injury / Q000175:diagnosis* / Q000503:physiopathology; D017682:Myocardial Stunning / Q000175:diagnosis* / Q000503:physiopathology; D010865:Pilot Projects; D013997:Time Factors; D016277:Ventricular Function, Left / Q000502:physiology*