Background: Recent studies have reported that adequate perfusion of the infarct-related artery improves survival in patients with myocardial infarction, independently of left ventricular pump function. However, it is not known whether or not this reduction in mortality is independent of myocardial viability within the infarct zone. The aim of this study was to evaluate the prognostic value of the patency of the infarct artery and the presence of myocardial viability in akinetic regions in patients with myocardial infarction.
Methods: Low-dose dobutamine echocardiography was performed in 154 patients with recent or previous myocardial infarction and known coronary anatomy. In each patient three vascular regions were defined. Each akinetic region was considered viable if function improved during dobutamine echocardiography, and irrorated by a not stenotic akinetic area-related artery if the supplying vessel had a stenosis < 75% or had been successfully revascularized within 1 month of dobutamine echocardiography.
Results: At follow-up of 34 +/- 14 months, 19 patients died of cardiac death. At univariate Cox analysis end-diastolic and end-systolic volumes, ejection fraction, previous myocardial infarction, regional wall motion score index, and stenosis of the akinetic area-related artery were related to mortality. At multivariate analysis, stenosis of the akinetic area-related artery remained a significant predictor of mortality (p = 0.04), with higher mortality (13/66 vs 6/88, p = 0.02) in patients with a stenotic akinetic area-related artery, without differences in ejection fraction (35 +/- 9 vs 34 +/- 10%). Mortality was lower in patients with myocardial viability if they had a not stenotic akinetic area-related artery (1/43 vs 4/21, p = 0.02), while no difference was found among non-viable patients, with or without stenosis of the akinetic area-related artery (5/45 vs 9/45).
Conclusions: The present study confirms the prognostic role of the patency of the infarct-related artery. However, it suggests that the lower mortality in patients with a patent artery supplying akinetic infarcted regions is related to the presence of myocardial viability in these regions.