Extravasated erythrocytes, iron, and fibrin in atherosclerotic plaques of coronary arteries in fatal coronary heart disease and their relation to luminal thrombus: frequency and significance in 57 necropsy patients and in 2958 five mm segments of 224 major epicardial coronary arteries.

The presence of extravasated erythrocytes (EE), iron (I), and fibrin (F) within coronary atherosclerotic plaques and their relation to intraluminal coronary thrombus was determined in 2958 five-mm segments of 224 major epicardial coronary arteries in 57 patients with fatal coronary heart disease and in 1290 five-mm segments of 103 coronary arteries in 27 control (c) subjects. Intraplaque EE were present in 10% of the segments (controls [c] = 1%), in 35% of the arteries (c = 5%), and in 84% of the patients (c = 19%); I was present in 4% of the segments (c = less than 1%), in 14% of the arteries (c = 4%), and in 57% of the patients (c = 22%); intraplaque F was present in 2% of the segments (c = less than 1%), in 17% of the arteries (c = 3%), and in 63% of the patients (c = 7%). Intraluminal thrombus, present only in the patients with acute myocardial infarction and in none of the controls, occurred in 3% of the segments, in 8% of the arteries and in 26% of the patients. Intraplaque hemorrhage or EE occurred usually in the absence of intraluminal thrombus and conversely intraluminal thrombus occurred more frequently without than with underlying plaque hemorrhage. The frequency of intraplaque EE, I, and F was proportional to the amount of coronary atherosclerotic plaque present. Intraplaque I and F infrequently were observed in the absence of EE. The significance of extravasated erythrocytes, iron, and fibrin in atherosclerotic plaques remains unclear.