[Association between structure of atherosclerotic plaques in carotid arteries and myocardial infarction]

Aim of this study was to investigate association between structure of atherosclerotic plaque (AP) in internal carotid artery and myocardial infarction (MI), as well as to elucidate factors which may determine expansion of APs into coronary arteries.

We studied 655 patients (148 with MI and 507 without MI) subjected to carotid artery enderterectomy. Degree of stenosis of brachiocephalic arteries (BCA) was proven by angiography. Carotid AP structure was assessed by ultrasonography and directly during endarterectomy. The following factors were registered: age, sex, fibrinogen level, presence of diabetes, hypertension, smoking, hypercholesterolemia, intermittent claudication, and atrial fibrillation.

Groups with and without MI did not differ significantly as regards age, sex, hypercholesterolemia, fibrinogen, diabetes, smoking, and degree of carotid artery stenosis. Patients with MI significantly more frequently had hypertension (75 vs. 63.9%, p=0.012), other than operated BCA stenosis >50% (58.1 vs. 46%, p<0.01), unstable carotid plaque (82 vs. 75.1%, p=0.026), carotid plaque hemorrhage (43.2 vs. 17.6%, p=0.001). Logistic regression analysis showed that the presence of unstable carotid plaque (odds ratio [OR] 2.3, 95% confidence interval [CI] 1.02-5.17, p=0.04) and significant stenosis in other BCAs (OR1.81, 95%CI 1-3.26, p=0.049) predicted unstable coronary artery disease expressed clinically as myocardial infarction.

BCA AP instability (especially plaque hemorrhage) and presence of stenosis >50% in more than one BCA may reflect expansion of unstable APs into coronary arteries and development of MI.