title: Anomalous left circumflex artery from the right coronary cusp: a benign variant?
abstract: OBJECTIVE
  To determine the incidence of angiographically evident coronary artery disease (CAD) of the anomalous left circumflex artery (ALCx).
  
  
  BACKGROUND
  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.
  
  
  METHODS
  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).
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Internal Medicine, St Louis University Hospital, St Louis, Missouri, USA.
authors.forename: Ghassan A
authors.initials: GA
authors.lastname: Mohsen
authors.forename: Khaja G
authors.initials: KG
authors.lastname: Mohsin
authors.forename: Michael
authors.initials: M
authors.lastname: Forsberg
authors.forename: Eric
authors.initials: E
authors.lastname: Miller
authors.forename: Megumi
authors.initials: M
authors.lastname: Taniuchi
authors.forename: Andrew J P
authors.initials: AJ
authors.lastname: Klein
mesh_terms: D050197:Atherosclerosis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000628:therapy; D006328:Cardiac Catheterization; D015331:Cohort Studies; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000628:therapy; D003330:Coronary Vessel Anomalies / Q000150:complications* / Q000000981:diagnostic imaging / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention; D012189:Retrospective Studies; D016896:Treatment Outcome