Frequency of severe (70% or more) narrowing of the right, left anterior descending, and left circumflex coronary arteries in right dominant circulations with coronary artery disease

Several studies suggest that atherosclerotic coronary artery disease (CAD) occurs relatively infrequently in the left circumflex coronary artery. Of 313 patients with angina pectoris whose coronary cineangiograms were reviewed by Diethrich et al,¹ 58 had at least 75% luminal diameter narrowing of only 1 coronary artery: 31 (53%) involved the left anterior descending coronary artery (LAD), 23 (40%) the right coronary artery and only 4 (7%) the left circumflex coronary artery (LC). A similar frequency of coronary artery involvement was reported in a series of postmortem studies by Roberts, Jones and Virmani^2-5: among 30 patients with narrowing of 1 coronary artery, in 18 (60%) the LAD was involved, in 11 (37%) the right coronary artery was involved and in only 1 patient (3%) was the LC involved. Feit et al⁶ reviewed the coronary cineangiograms of 54 patients with 1-vessel CAD, only 7 (13%) of whom had LC involvement. No previously published study has confirmed the infrequency of LC involvement in a large number of patients with 1-vessel CAD, nor have the relative frequencies of vessel involvement in patients with 2-vessel CAD been examined to ascertain if the relatively infrequent LC involvement occurs in these patients.