Angiographic progression of coronary artery disease and the development of myocardial infarction

Abstract

There are few data on angiographic coronary artery anatomy in patients whose coronary artery disease progresses to myocardial infarction. In this retrospective analysis, progression of coronary artery disease between two cardiac catheterization procedures is described in 38 patients: 23 patients (Group I) who had a myocardial infarction between the two studies and 15 patients (Group II) who presented with one or more new total occlusions at the second study without sustaining an intervening infarction.In Group I the median percent stenosis on the initial angiogram of the artery related to the infarct at restudy was significantly less than the median percent stenosis of lesions that subsequently were the site of a new total occlusion in Group II (48 versus 73.5%, p < 0.05). In the infarctrelated artery in Group I, only 5 (22%) of 23 lesions were initially >70%, whereas in Group II, 11 (61%) of 18 lesions that progressed to total occlusion were initially >70% (p < 0.01). In Group I, patients who developed a Q wave infarction had less severe narrowing at initial angiography in the subsequent infarct-related artery (34%) than did patients who developed a non-Q wave infarction (80%) (p < 0.05). Univariate and multivariate analysis of angiographic and clinical characteristics present at initial angiography in Group I revealed proximal lesion location as the only significant predictor of evolution of lesions ≥ 50% to infarction.This irrespective study suggests that myocardial infarction frequently develops from previously nonsevere lesions. In addition, it is often difficult to predict the location of a subsequent infarct from analysis of the first coronary angiogram. Non-Q wave infarction is usually preceded by a more severe pre-existing stenosis than is a Q wave infarction, perhaps indicating some degree of prior myocardial protection. A prospective evaluation will be necessary to confirm these findings.