Coronary Artery Anomalies (CAAs)

What are coronary artery anomalies?

The heart muscle requires a regular supply of oxygen and food. This is supplied by blood carried by two blood vessels known as the left and right coronary arteries which come from the left and right side of the body’s main artery, the aorta. In 1 in 100 people both coronary arteries come from the same side of the aorta. This is called an ‘anomalous coronary origin’ or ‘coronary artery anomaly’. The unusual origin of the artery means that the artery must take a different route to supply the heart muscle. In the majority of people this causes no problems. However, in a small number, the abnormal route can cause the anomalous coronary artery to be squashed or kinked during exercise. If the blood supply to the heart is disturbed then it can cause chest pains or dangerous arrhythmias. The cause of coronary artery anomalies is not known; however, in most cases they do not appear to be inherited.



If a person has a dangerous coronary artery anomaly they may experience warning symptoms, including chest discomfort or blackouts that usually happen during exercise.


How are coronary artery anomalies diagnosed?

Looking for coronary artery anomalies can be difficult because an ECG and even an exercise ECG are usually normal, even if a person is at high risk. The artery origin can be seen using an ECHO; if both arteries are not clearly seen then a more detailed heart scan, such as cardiac MRI or computed tomography (CT), can be used.



A person with a low-risk anomaly may not require treatment, or may be treated with beta-blockers and advised to avoid high levels of physical exertion. If high-risk anomalies are found then surgery to reconnect the artery to the right side of the aorta can be lifesaving.