Morphological and quantitative angiographic analyses of progression of coronary stenoses: A comparison of Q-wave and non-Q-wave myocardial infarction

Abstract

Background: The purpose of this study was to determine differences in coronary stenosis severity and morphology and time course of progression between Q-wave and non-Q-wave myocardial infarction (MI). Methods and Results: We studied 32 patients with new Q-wave MI and 38 patients with new non-Q-wave MI who underwent coronary angiography both before and after MI without interval revascularization procedures. Quantitative coronary angiographic analysis was performed by the caliper method, and morphological analysis of coronary angiograms was obtained before and soon after acute MI. Before infarction, the stenosis severity at the site of future MI was worse in Q-wave (44±25%) versus non-Q-wave (23±35%) MI patients (P <18 months later had a stenosis of ≥50% versus 7 of 21 (33%) with an interval >18 months (P <20%) or else a severe stenosis (>70%) was typically present. Conclusions: The atheromatous plaque substrate is different in Q-wave and non-Q-wave MI. Non-Q-wave MI occurs typically at a site shown by pre-MI angiography to involve either minimal luminal narrowing or a severe stenosis before MI, which is usually nonulcerated. By comparison, Q-wave MI follows a moderate stenosis in which the plaque is eccentric and ulcerated. Such differences culminate in differences in thrombus lability and collateral development and consequently in different clinical profiles.