Coronary CT angiography in a 24-year-old athlete who survived a cardiac arrest shows the right coronary artery arising from the left coronary sinus and taking a course between the aortic root and the main pulmonary artery before reaching the right atrioventricular groove. Why does this variant carry a risk of sudden death?
- A The vessel is compressed between the aorta and pulmonary artery during exercise ✓
- B The anomalous ostium is protected from atherosclerosis, masking ischaemia
- C The vessel supplies the conduction system exclusively
- D The vessel always develops aneurysmal dilatation
Correct answer: A. The vessel is compressed between the aorta and pulmonary artery during exercise
Explanation
An interarterial (malignant) course places the anomalous coronary between the great arteries. During exertion, both the aorta and pulmonary artery expand, compressing the vessel, often compounded by an acute angle take-off and a slit-like ostium, leading to exercise-induced ischaemia, arrhythmia and sudden death. This anatomy is an accepted indication for surgical correction in symptomatic or high-risk patients. The other options describe mechanisms that do not apply to this entity.
Reference: Grainger and Allison's Diagnostic Radiology, 7th ed.
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