Segmental analysis of coronary arterial stenoses in patients presenting with angina or first myocardial infarction.

The segmental distribution of stenoses within the coronary arteries was analysed in a population of 258 patients with a first myocardial infarction undergoing coronary angiography to evaluate the effect of thrombolytic therapy, and in a population of 466 patients undergoing elective coronary angiography for stable angina. Mean ages were 53.7 and 56.7 years respectively (P = NS). As judged angiographically, coronary arterial disease was more extensive in the group suffering angina, with a greater proportion of patients with two- or three-vessel disease (odds ratio 2.56, 95% confidence interval 1.87 to 3.52) and more patients having stenoses in two or more coronary arterial segments (odds ratio 1.52, 95% confidence interval 1.12 to 2.08). For each coronary vessel, the probability of finding a stenosis greater than 50% in an individual segment was greater in the group presenting with angina. There was a relative deficiency of stenoses within the main stem of the left coronary artery or its proximal left anterior descending branch among the patients suffering myocardial infarction. Within those having angina, subgroups were identified with "isolated" and "diffuse" coronary arterial disease: the latter patients tended to have a lower concentration of total cholesterol in the serum, but an increased prevalence of diabetes mellitus. Patients presenting clinically with a first myocardial infarction, and patients with severe angina, constitute distinct populations selected by different mechanisms from the overall pool of patients with atheromatous coronary arterial disease.