Effect of coronary artery size on the prevalence of atherosclerosis.

To investigate the effect of coronary artery size on the prevalence of atherosclerosis, we measured the diameters of the major coronary arteries prospectively in 884 consecutive patients referred for coronary arteriography. For each artery, we assigned patients to 3 groups: group S (small) and group L (large) with diameters >1SD smaller and larger, respectively, than the mean; and group A (average), with diameters within 1SD of the mean. As specified during study design, we compared the frequency of lesions > or = 50% diameter stenosis in groups S and L for each artery. We adjusted for relevant covariates by performing logistic regression on data from all 884 patients with coronary diameter entered as a continuous variable. In group S versus L, respectively, the frequency of > or = 50% lesion was 6.5% versus 2.4% (p = 0.13) in the left main artery; 61.3% versus 35.8% (p = 0.0001) in the right coronary artery; 58.1% versus 40.7% (p = 0.008) in the left anterior descending artery, and 47.4% versus 22.2% (p = 0.0001) in the circumflex artery. Multivariate analysis showed that coronary diameter was a significant independent predictor of lesions in the right coronary artery (p = 0.000001), left anterior descending artery (p = 0.001), and circumflex artery (p = 0.0002) and nearly significant in the left main artery (p = 0.077). Thus, small coronary artery size may be a risk factor for atherosclerosis.