A coronary artery anomaly (CAA) is a defect in one or more of the coronary arteries of the heart. The defect is congenital (present at birth). CAAs may relate to the origin (where the artery "springs up" in the heart) or the location of the coronary artery. However, the term CAA can be used to describe any defects in a coronary artery, such as an abnormal size or shape. They are often found in patients with other congenital heart diseases.  

Another name for a CAA is an anomalous coronary artery (ACA).

What are the causes?

Doctors do not know the exact causes of CAAs. There are many steps in the development of the coronary arteries in the fetal heart. If anything goes wrong during any of these steps, it can lead to a CAA.  

Some congenital heart diseases are strongly linked to CAAs, including persistent truncus arteriosus, transposition of the great arteries, pulmonary valve atresia, double outlet right ventricle (DORV), and tetralogy of Fallot.  

Some studies have shown that certain types of CAAs can run in families, but doctors have not yet found a solid pattern to say for sure that CAAs may be hereditary.  

Coronary artery anomalies are found in about 5% of people who undergo cardiac catheterization to find out why they are having chest pain.

What are the risks of a CAA?

Because the coronary arteries deliver oxygen-rich blood to the heart muscle, a defect or disease in a coronary artery may reduce the amount of oxygen and nutrients that the heart receives. CAAs can lead to myocardial ischemia (a lack of blood to the heart muscle) and sudden cardiac death.

Athletes or people who take part in strenuous physical activities are especially at risk of sudden cardiac death if they have a CAA. In fact, CAAs are the second leading cause of death in young athletes. Between 15% and 34% of young people who experience sudden cardiac death are later found to have a CAA. When news stories talk about young athletes dying suddenly, it is usually because those athletes had either hypertrophic cardiomyopathy or a CAA.

What are the symptoms of a CAA?

Only a few kinds of CAAs will cause symptoms. For some people, the symptoms can begin in childhood, while others may not have symptoms until adulthood. But most people with a CAA do not even know they have the condition, either because they do not have any symptoms at all or because sudden cardiac death occurs. 

In babies and children, some of the symptoms of a CAA may include

• Breathing problems
• Pale skin
• Poor feeding
• Sweating  

In teens and adults, the symptoms of a CAA may include

• Fainting during strenuous exercise (often the first and most dramatic symptom of a CAA)
• Shortness of breath at rest or during exercise
• Fatigue
• Chest pain at rest or during exercise

Sudden cardiac death (also called sudden cardiac arrest) is the most dangerous symptom of a CAA. It is thought to happen because the abnormal coronary artery gets "squashed" between larger arteries that become stretched with blood during exercise. This means that less blood can reach the heart, which can lead to sudden death.

How is a CAA diagnosed?

Doctors will perform a physical examination and listen to the heart and lungs using a stethoscope. Other tests may include 

• Echocardiography to show the size of the heart and how much muscle damage there is.
• Magnetic resonance imaging (MRI) to get a detailed image of the heart, including the coronary arteries to see if there are any CAAs. And magnetic resonance angiography (MRA) to evaluate blood flow through the arteries.
• Angiography, a cardiac catheterization procedure, to get a very detailed view of a CAA.
• Transesophageal echocardiography to get pictures of the heart from inside the esophagus rather than through the chest wall.
• Computed tomography (CT) scanning, especially electron beam computed tomography (EBCT), to get a good picture of the coronary arteries.
• Nuclear imaging tests to see if blood flow to the heart is abnormal and if there is any damage to the heart muscle.

How are CAAs treated?

Treatments include lifestyle changes, medicines, percutaneous coronary interventions, and surgery.  

Lifestyle changes
Patients with a known and serious CAA must stay less physically active and avoid exercising too much and taking part in certain types of sports.  

Medicines
For patients with mild to moderate symptoms, medicines may be used, especially to prevent sudden cardiac death.

• Beta-blockers slow the heartbeat.
• Diuretics (water pills) reduce excess fluid in the body, relieving the stress on the heart's pumping action.
• Antiarrhythmic medicines help to regulate the heartbeat.
• Oxygen therapy increases the amount of oxygen-rich blood that reaches the heart.  

Percutaneous coronary interventions
Some types of CAAs can be corrected by placing a stent in the artery with the CAA. This procedure is done in the cardiac catheterization laboratory.  

Surgery
Surgery is sometimes performed to correct a CAA. The type of surgery needed depends on the type of CAA.  

Center for Coronary Artery Anomalies
Doctors at the Texas Heart Institute's Center for Coronary Artery Anomalies (CCAA) are working to increase awareness about CAAs and to develop a screening program to help prevent sudden cardiac death in young athletes with CAAs.  

See also on this site:

• Sudden Cardiac Arrest
• Congenital Heart Disease