Quantitation of coronary arterial narrowing at necropsy in sudden coronary death: analysis of 31 patients and comparison with 25 control subjects.

A quantitative analysis of the degree and extent of coronary arterial narrowing by atherosclerotic plaques in the entire lengths of each of the four major coronary arteries in a group of patients dying suddenly from coronary heart disease ("sudden coronary death") is described at necropsy. Cross sections were examined histologically in a total of 1,564 five mm long segments of the left main, left anterior descending left circumflex and right coronary arteries in 31 patients with sudden coronary death, and the observations were compared with those from examination of 1,100 five mm segments of the major epicardial coronary arteries in 25 control subjects. An average of 25 cm (50 five mm segments) of coronary artery were examined from each patient and an average of 22 cm (44 five mm segments) from each control subject. Of the 1,564 five mm segments examined in the 31 study patients, 557 (36 percent) were 76 to 100 percent narrowed in cross-sectional area by atherosclerotic plaques (control subjects 3 percent), 536 (34 percent) were 51 to 75 percent narrowed (control subjects 22 percent), 360 (23 percent) were 26 to 50 percent narrowed (control subjects 42 percent) and only 111 segments (7 percent) had 25 percent or less narrowing (control subjects 33 percent). The amount of severe (greater than 75 percent) narrowing of the right, left anterior descending and left circumflex coronary arteries was similar. Additionally, the amount of severe (greater than 75 percent) narrowing in the distal one half of the right, left anterior descending and left circumflex coronary arteries was similar to that in the proximal halves of these three arteries. The number of 5 mm coronary arterial segments narrowed 76 to 100 percent in cross-sectional area in the 31 study patients was not affected by the patient's age of death, sex, presence or absence of previous angina pectoris or myocardial infarction or the weight of the heart.