Role of plaque size and degree of stenosis in acute myocardial infarction.

Angiographically apparent coronary artery stenoses limit coronary flow, produce symptomatic ischemia, and can be targeted for revascularization. Severe stenoses are more likely to occlude than segments without significant stenoses. Coronary angiography underestimates the extent of coronary atherosclerosis. Arterial segments without severe stenoses are much more common, and their risk of occlusion is not zero. Thus, the majority of myocardial infarctions are due to occlusion of arteries that do not contain obstructive coronary stenoses. Consequently, coronary angiography is not able to accurately predict the site of a coronary artery occlusion that subsequently will produce myocardial infarction.