Anomalous Coronary Arteries

Anomalous Coronary Arteries

Anomalous coronary arteries is a defect that is very rare, but it is the one defect that makes the news in every newspaper about once a year or so.

“Marine Dies in Grueling Basic Training”. “Football Star Dies During Intense Workout”. “Track Star Dead Following Heavy Training”.

Two years ago, in Milwaukee, a young female died after dancing all night, and collapsed after a very strenuous night out.

These are the headlines that you see the next day, and everyone wonders how this can happen. What really caused this death in a very young person may not be followed up in the media, but post-autopsy results often diagnose anomalous coronary arteries.

Coronary arteries feed the heart muscle with oxygen rich blood and emerge from the aorta at two points just above the cusps of the aortic valve, the right and left coronary cusps. Most simply speaking, the right coronary artery feeds the right side of the heart, and the left coronary artery feeds the left side of the heart. The word “anomalous” means “that which is irregular or deviates from the normal”. Hence, anomalous coronary arteries are a defect that results when these arteries arise from their point of origin abnormally.

There are three primary types of anomalous coronary arteries, some of which need to be surgically repaired and others that typically do not get repaired. These defects may not identified early in life, but eventually symptoms will occur. These may include angina, cardiomegally (enlarged heart), ECG abnormalities that may resemble a myocardial infarction (heart attack), or congestive heart failure (CHF).

Left Main Coronary Artery Arising from the Pulmonary Artery
This is the most common defect among anomalous coronary arteries and requires surgical intervention. Since the left coronary artery arises from the pulmonary artery, this means that the coronary artery is being fed de-oxygentated right sided blood with oxygen levels around 70% rather than 99% in a normal artery. The right coronary artery emerges properly from the aorta an has normal oxygen levels.

Without proper oxygenation in the left main coronary artery, the entire left side of the heart is essentially “starved” for adequate perfusion.

The goal of surgical repair is to re-establish a proper 2-coronary artery system. Ideally, the left main coronary artery is detached from the pulmonary artery and re-attached to the aorta. If this is not possible, then an artificial “tunnel” (aortopulmonary window) is excised between the aorta and the pulmonary artery through the right ventricular outflow tract and completed with a patch. This re-directs normal blood flow from the aorta into the left main coronary artery.

Left Main Coronary Artery Arising from the Right Coronary Artery
This a less serious defect in that there is fully saturated flow in the left main coronary artery. However, if the left main coronary artery courses between the aorta and pulmonary artery, this may result in the coronary artery being “trapped”, or compressed during physical exertion.

All arteries pulse, or dialate and contract with every beat of the heart. During exertion, this pulse is exaggerated, and this causes the trapped coronary artery to close up as the aorta and pulmonary artery expand and contract. The resulting lack of perfusion to the left side of the heart may cause chest pain, angina or even sudden death.

If surgical repair is required, it will involve using either the mammary artery or an intra-aortic tunnel to create an enlarged path of flow for the left main coronary artery between the aorta and pulmonary artery.

Right Coronary Artery Arising from the Left Main Coronary Artery
This also known as “single coronary artery”. The vessel is fully saturated with oxygen and there is usually no surgical intervention unless the right coronary artery is trapped between the aorta and the pulmonary artery.

Surgical intervention is uncommon but would follow the same procedure outlined above if needed.

Tips for Sonographers
The coronary arteries are best visualized in the parasternal short axis view at the level of the aortic valve. Here the non, right and left coronary cusps of the aortic valve are seen. The left main coronary artery is usually well visualized as it arises from its origin at the level of the left coronary cusp of the aortic valve.

The right coronary artery is often more difficult to see, but if you angulate the probe slightly superiorly and rotate a little clockwise, the vessel can be seen originating from the level of the right cusp of the aortic valve. If you angulate properly, you can usually see several millimeters of the right coronary artery.

Don’t be afraid to work with these angles as you move the probe around, and remember that these adjustments are very slight. As with all babies, you do not have the same limitations visualizing the heart as you do with adults. The rib cages of babies are very cartilaginous and the bones have not ossified yet, so it is easy to view the heart from many different locations and angles.

Experiment! Make up your own views. Move that probe around and look at these structures from many different angles.

ken Heiden RDCS

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