Anomalous aortic origin of a coronary artery (AAOCA) occurs when a coronary artery originates from the inappropriate (opposite) sinus of Valsalva. For example, the left coronary artery (ALCA) may arise from the right sinus, or the right coronary artery (ARCA) may arise from the left sinus.
CCTA is the gold standard for evaluating AAOCA — it perfectly defines the vessel’s 3D spatial relationship to surrounding structures (aorta and pulmonary artery), which is exactly what determines clinical significance.
These anomalies are broadly stratified into “malignant” or “benign” based on the vessel’s subsequent path.
1 Benign courses
The anomalous artery may take one of three benign paths:
- Prepulmonic — anterior to the pulmonary artery
- Retroaortic — dorsal to the aortic root
- Subpulmonic / transseptal — diving through the interventricular septum
These are generally asymptomatic, incidental findings with an excellent prognosis.
2 The malignant variant
If the anomalous artery takes an interarterial course — routing directly between the ascending aorta and the pulmonary artery / RVOT — it is classified as malignant. This is the dangerous variant: see Interarterial course for the full picture, including high-risk CTA features and management.