Anomalous left circumflex artery from the right coronary cusp: a benign variant?

To determine the incidence of angiographically evident coronary artery disease (CAD) of the anomalous left circumflex artery (ALCx).

Due to the acute angulation of its origin from the aorta and its retroaortic course, some have proposed an increase in CAD in these vessels.

We performed a retrospective cohort study of all patients (n = 5205) presenting for left heart catheterization at the St Louis Veterans Affairs hospital from 2006-2012. Quantitative coronary angiography (QCA) was performed by two independent operators for all cases identified as having ALCx (n = 18).

We identified 18 patients (0.346%) with this anomaly. Sixteen of 18 cases (89%) had atherosclerosis involving the ALCx. QCA performed on the ALCx for all 18 patients resulted in a mean stenosis of 61% (range, 10%-100%). Seven out of 18 patients (39%) had obstructive CAD of the ALCx with the majority (n = 6; 86%) also having concomitant obstructive disease in the left anterior descending (LAD) or right coronary artery (RCA). In the 5 cases where the ALCx underwent intervention, the mean diameter stent was 2.25 mm, with a mean length of 15 mm, indicating that these vessels were small in caliber with focal disease. At a mean follow-up of 18 months for all patients, there was 1 non-cardiac death in the non-intervened group, with the 17 remaining patients (94.7%) free of major adverse cardiovascular events (target lesion revascularization, target vessel revascularization, or death).

This study suggests that indeed this most common anomaly appears to be benign in that its unique origin and/or retroaortic course do not increase the occurrence of atherosclerosis relative to the LAD and RCA.