Anomalous Coronary Artery (ACA)

What is ACA?

An anomalous coronary artery (ACA) is a coronary artery that has an abnormality or malformation. The malformation is congenital (present at birth) and is most often related to the origin of the coronary artery. However, there may be other defective areas in the coronary artery.  ACA may also occur along with other congenital heart defects.

This condition may also be called congenital coronary artery anomaly (CAA).

Although they are present at birth, ACAs are often not diagnosed until late adolescence or adulthood, because of the lack of symptoms or because symptoms may not be recognized as being caused by ACA. Teens or adults with unknown ACA may have an initial episode of chest pain, heart failure, or even sudden cardiac death before the condition is recognized.

Anatomy of the coronary arteries

The main function of the coronary arteries is to supply blood to the heart muscle. Like all other tissues in the body, the heart muscle needs oxygen-rich blood to function, and oxygen-depleted blood must be recirculated to the lungs. The coronary arteries are made up of two large branches called the right and left coronary arteries. The left coronary artery system branches into the circumflex artery and the left anterior descending artery.

Illustration showing the outside of the heart and the coronary arteries

The two main coronary arteries are the left main and right coronary arteries. The left main coronary artery (LMCA), supplies blood to the left ventricle. The right coronary artery (RCA), supplies blood to the right ventricle, right atrium, and sinoatrial node (cluster of cells in the right atrial wall that regulates the heart's rhythmic rate).

Additional arteries branch off the two main coronary arteries to supply the heart muscle with blood. These include the following:

  • Circumflex artery (Cx). The circumflex artery branches off the left coronary artery and encircles the heart muscle. This artery supplies blood to the lateral side and back of the heart.

  • Left anterior descending artery (LAD). The left anterior descending artery branches off the left coronary artery and supplies blood to the front of the left side of the heart.

Smaller branches of the coronary arteries include: acute marginal, posterior descending (PDA), obtuse marginal (OM), septal perforator, and diagonals.

Why are the coronary arteries important?

Since coronary arteries deliver blood to the heart muscle, any coronary artery disorder or disease can potentially reduce the flow of oxygen and nutrients to the heart, which may lead to a heart attack or death.

What causes ACA?

The vast majority of congenital heart defects have no known cause. A baby's heart begins to develop at conception, and is largely formed by eight weeks into the pregnancy. Congenital heart defects develop during this crucial first eight weeks of the baby's development. Specific steps must take place in order for the heart to form correctly. Often, congenital heart defects are a result of one of these crucial steps not happening at the right time.

ACA may be associated with other congenital heart defects, particularly transposition of the great arteries and tetralogy of Fallot.

Why is ACA a concern?

ACA is of concern because there may be no indication that the condition is present until a severe event, such as chest pain, heart attack, or even sudden death occurs. A child may have remained asymptomatic (free from symptoms) throughout childhood, and be completely unaware that he or she had a problem.

Individuals with ACA involved in strenuous activity or athletics may be at risk for sudden death and may need to modify their exercise routines. Some young people who experience sudden cardiac death are found to have a coronary artery anomaly. ACA is the second most common cause of sudden death in young athletes.

It is also suspected that anomalous coronary arteries may pose risk for earlier development of coronary atherosclerotic disease.

What are the symptoms of ACA?

The symptoms of ACA vary depending on the type of anomalous artery present. Some types have no associated symptoms and may be found later in life during diagnostic tests, such as cardiac echocardiography (echo) or cardiac catheterization. Other types of ACA may cause symptoms related to decreased blood flow to the heart tissue, such as chest pain on exertion or (less commonly) at rest.

Depending on the type of ACA, symptoms may begin in infancy, or, more commonly, they may not appear until later on in life. An infant with ACA may exhibit symptoms that may include, but are not limited to, the following:

  • Irritability

  • Poor feeding

  • Slowed or poor growth and development

  • Dyspnea (difficulty breathing)

  • Wheezing

  • Diaphoresis (sweating)

  • Grayish skin color in conjunction with other symptoms

  • Periods of pallor (pale skin)

  • Heart failure

An older child may complain of chest pain or dizziness and fainting during exertion. Heart failure, with symptoms of shortness of breath on exertion and fluid retention, may be the hallmark symptom if chest pain has been vague or ignored and ischemia (decreased blood flow to the heart muscle) damaged the heart muscle.

Both chest pain and heart failure symptoms serve as early warning signs in adults that the heart muscle is no longer receiving sufficient blood supply from the coronary artery circulation, which may have been adequate during infancy and childhood.

The symptoms of an anomalous coronary artery may resemble other medical conditions or heart problems. Always consult your child's doctor for a diagnosis.

How is ACA diagnosed?

The doctor will perform a physical examination, listening to the heart and lungs, and make other observations that help in the diagnosis. 

Diagnostic testing for congenital heart disease varies by the child's age, clinical condition, and institutional preferences. Some tests that may be recommended include the following:

  • Chest X-ray. A diagnostic test that uses invisible X-ray beams to produce images of internal tissues, bones, and organs onto film. There may be changes that take place in the lungs due to extra blood flow that can be seen on an X-ray.

  • Electrocardiogram (ECG or EKG). A test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle stress.

  • Echocardiogram (echo). A procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor to produce a moving picture of the heart and heart valves.

  • Cardiac catheterization. A cardiac catheterization is an invasive procedure that gives very detailed information about the structures inside the heart. Under sedation, a small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin, and guided to the inside of the heart. Blood pressure and oxygen measurements are taken in the four chambers of the heart, as well as the pulmonary artery and aorta. Contrast dye is also injected to more clearly visualize the structures inside the heart.

  • Computed tomography angiography (CTA). A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the blood vessels.

  • Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.

  • Magnetic resonance angiography (MRA). A type of MRI procedure used to evaluate blood flow through arteries.

  • Nuclear imaging. Diagnostic scans that use very small amounts of radioactive materials, or radiopharmaceuticals, to identify abnormal blood flow to the heart, to determine the extent of the damage of the heart muscle after a heart attack, and/or to measure heart function.

ACA may be found during diagnostic procedures performed for symptoms that are related to other problems or conditions.

Treatment for ACA

Specific treatment for anomalous coronary artery will be determined by your child's doctor based on:

  • Your child's age, overall health, and medical history

  • Extent of the disease

  • Your child's tolerance for specific medications, procedures, or therapies

  • Expectations for the course of the defect

  • Your opinion or preference

Recommendations for treatment will depend on which type of ACA is present and its effect on the child. Treatment for ACA may include:

  • Medical treatment. Various methods of medical treatment for ACA may include:

    • Medications to strengthen the heart, affect the blood pressure, and/or remove extra fluid from the body (water pills). Other types of medications may also be used.

    • Oxygen therapy

    • Activity limitations

  • Surgical treatment. Various surgical techniques may be utilized for ACA repair, depending on the type of anomaly.

Long-term outcomes

Depending on the specific form of ACA, symptoms may be absent or mild in childhood.

Individuals who have been diagnosed with ACA should follow their doctor's recommendations closely. Although many remain without symptoms, a thorough evaluation again in adolescence or early adulthood is recommended. In some cases, periodic stress tests may be recommended to assess for changes in coronary artery status.

Following surgical repair of ACA, there may be some increased risk of developing early coronary artery disease. Outcomes following surgical repair may be improved by following guidelines for healthy diet and exercise.

Consult your child's doctor regarding the specific outlook for your child.

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