Presentation
Atypical chest pain, with unusual catheter angiogram. CT for characterization.
Patient Data
The LCA ostium arises conventionally from the left coronary sinus. The right coronary sinus has separate ostia for the RCA (red arrow), conus branch (yellow arrow), and circumflex artery (blue arrow). The circumflex artery is seen to have a retro-aortic course, passing between the aorta and left atrium.
Case Discussion
Anomalous origin of the circumflex artery from the right coronary sinus is a well recognized variant. The artery passes in a retro-aortic location, and this variant is not thought to be haemodynamically significant. This is a non-malignant course, as it does not pass between two arterial structures.
The significance of this anomaly is that it may cause difficulty in catheterization and interpretation at catheter angiogram. In contrast, cardiac CT easily elucidates the course of anomalous coronary arteries. A further clinical significance is that the circumflex artery partially encircles the aortic valve in this course, and may be damaged at arteriotomy in valve surgery if this anomalous course has not been recognized. Also it may be compressed following implantation of a prosthetic aortic valve.