Quantification of coronary arterial narrowing at necropsy in acute transmural myocardial infarction. Analysis and comparison of findings in 27 patients and 22 controls.

We quantitatively analyzed the degree and extent of coronary arterial narrowing by atherosclerotic plaques in the entire length of each of the four major coronary arteries in 27 necropsy patients with transmural acute myocardial infarction (AMI) and compared the findings with those in 22 control subjects. Of the 1403 5-mm segments examined in the 27 AMI patients, 484 (34%; controls 3%) were 76-100% narrowed in cross-sectional area by atherosclerotic plaques, 528 (38%; controls 25%) were 51-75% narrowed, 319 (23%; controls 44%) were 26-50% narrowed, and only 72 segments (5%; controls 28%) were less than or equal to 25% narrowed. The amount of severe (greater than 75%) narrowing of the right, left anterior descending and left circumflex coronary arteries by atherosclerotic plaques was similar, as was the amount of severe narrowing in the distal and proximal halves of these three arteries. The number of severely narrowed 5-mm segments did not correlate significantly with the patient's age at death, the presence or absence of a history of angina pectoris or healed myocardial infarction, or with heart weight. The men, however, had a significantly greater number of severely narrowed 5-mm segments of coronary artery than the women (p less than 0.05), and the patients with associated transmural left ventricular scars had significantly more severely narrowed segments than did patients without transmural scars.