The distribution of atherosclerotic lesions in the coronary arterial tree: relation to cardiac risk factors.

Although it is often stated that proximal atherosclerotic coronary artery disease occurs more frequently than distal disease, several autopsy studies have disputed this. To examine the prevalence of proximal vs mid and distal disease and its relationship with cardiac risk factors, we studied more than 14,000 sections from 102 hearts with coronary artery disease at autopsy. After postmortem angiography, the coronary arteries were removed, divided into proximal, mid, and distal thirds, sectioned at 2.5 mm intervals, and graded for percentage reduction in cross-sectional area by atherosclerosis. Of 252 vessels in 84 patients with greater than or equal to 75% stenosis, 166 (66%) has proximal disease vs 107 (42%) with mid disease and 40 (16%) with distal disease (p less than 0.001). No patient had a mid or distal stenosis greater than 75% without proximal disease. When atherosclerosis of any severity was assessed, proximal atherosclerotic lesions were long and diffuse, whereas distal lesions were more often short and discrete. Proximal circumflex lesions were shorter in length than those in the right or left anterior descending coronary arteries. The prevalence of proximal, mid, and distal stenoses in 25 diabetic patients was similar to that in nondiabetic persons (53%, 47%, and 17%, p greater than 0.3). Similarly, hypertension, smoking, and obesity were not associated with an increase in prevalence of distal disease. Patients with distal stenoses were younger than patients without (mean age, 64 +/- 13 vs 73 +/- 10 years, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)