What is Coronary Artery Anomalies?

As health care providers increasingly use a special type of heart scan known as coronary computed tomography angiography (CCTA) to treat patients with sudden chest pain, they are likely to encounter unusual properties or changes in the coronary arteries more often. While most of these irregularities are not serious, some can limit blood flow, causing muscle damage in the heart. Therefore, it’s crucial to differentiate between these serious cases that may need intervention, and the everyday variations of the coronary artery that pose minimal or no risk to the patient.

What Causes Coronary Artery Anomalies?

Coronary artery anomalies are irregularities in the heart’s arteries that happen due to an abnormal development. These can involve changes in different aspects of the vessel, including:

* The origin, or where it starts (for instance, it may develop from a different part of the aorta than usual)
* The course, or path it follows (it may run through the aorta in an unusual way)
* The termination, or endpoint (it may end in a coronary-cameral fistula, which is an abnormal connection between the artery and a chamber of the heart)
* The morphology, or shape and form (it may develop an aneurysm, which is a bulge in the wall of the artery).

Risk Factors and Frequency for Coronary Artery Anomalies

An anomaly is defined as a developmental abnormality found in less than 1% of the population. It is different from an anatomical or normal variant, which is found in more than 1% of the population. For this explanation, the term “anomaly” will be used to refer to both.

Coronary artery anomalies, which are abnormalities in the arteries that supply blood to the heart, occur in about 0.78 to 1.3% of the population. This data comes from cardiac angiography, a test that uses dye and special x-rays to show the blood flow in the heart’s arteries. However, when coronary CT angiography (CCTA), a heart imaging test, is used, the incidence of these anomalies goes up to 0.99% to 5.8%. This is because the CCTA test is more sensitive and includes more criteria than angiography.

One such anomaly that can be seen on CCTA is called an intramyocardial course, also known as a myocardial bridge. In this condition, the coronary artery, usually the one called the left anterior descending, does not run on the surface of the heart as it normally would. Instead, it at least partially runs a deeper course within the left ventricular muscle of the heart. This condition is common, usually unimportant clinically, and may not be visible on angiography.

However, in rare cases, the intramyocardial course can compress the artery because of the left ventricular muscle’s natural contraction. This could lead to a lack of blood flow in the heart from the prolonged compression. It could also make the patient more prone to a tear in the coronary artery, rupture of the plaques in the artery, or coronary spasm, which means sudden narrowing of the artery. These conditions are caused by the effects of contraction on the artery.

Signs and Symptoms of Coronary Artery Anomalies

Most of the time, you won’t be able to tell if someone has a coronary artery anomaly just by examining them. However, if the anomaly is causing issues with blood flow, symptoms may appear. These issues can often lead to symptoms similar to those of reduced blood supply to the heart, including chest pain, shortness of breath, and difficulty breathing. In rare cases, it may even result in sudden cardiac death. It’s also interesting to note that high flow anomalies, such as coronary artery fistulas or an anomalous left coronary artery from the lung artery, might produce an unusual continuous sound that can be heard during examination.

Chest pain
Shortness of breath
Difficulty breathing
Rarely, sudden cardiac death
An audible continuous murmur in case of high flow anomalies

Testing for Coronary Artery Anomalies

The American College of Cardiology Foundation approves of Coronary Computed Tomography Angiography (CCTA) for checking abnormal coronary arteries. CCTA is considered the standard method because it’s fast and accurate. However, it does expose patients to a certain amount of radiation.

Another option is Cardiac MRI, which has slightly less detailed imaging than CCTA, but it avoids exposing the patient to radiation. This technique is also deemed appropriate for testing suspect coronary artery abnormalities.

Treatment Options for Coronary Artery Anomalies

Most of the time, irregularities found in the coronary arteries, the heart’s main blood vessels, are harmless and incidental, requiring no treatment. However, for those that do cause symptoms, the specific treatment used will depend on the type of abnormality present.

For example, a condition known as ALCAPA, in infants needs a surgical procedure to reposition the irregular artery and restore normal heart circulation. In adults, this condition can sometimes be managed without surgery if it results in moderate, persistent disruptions to the heart’s blood supply.

For significant anomalies that affect the way blood flows through the heart, like when an artery originates from the wrong place and follows a course within the heart’s wall, surgery may be needed. This can either involve opening up the section of the artery within the heart’s wall or using a heart bypass graft, which is essentially a detour around the blocked artery.

Coronary artery fistulas, which are abnormal connections between the coronary arteries and other parts of the heart or blood vessels, often don’t close on their own, with a spontaneous closure rate of only 1 to 2%. Instead, a procedure using catheters (long, thin tubes) is usually preferred to administer treatment as it carries less risk of complications. These treatments can involve inserting devices or substances to block off the abnormal connection. However, if these catheter procedures fail or aren’t suitable, then surgical repair becomes an option.

In contrast, for internal anomalies, like when an artery follows a course within the heart muscle or just beneath the inner heart lining, treatment is typically not necessary.

Abnormalities in the coronary arteries, which supply blood to the heart, can sometimes cause symptoms similar to those of a heart attack. However, such abnormalities are far less common in adults than blockages caused by the buildup of fatty plaques (atherosclerosis), which can also lead to a heart attack. In rare cases, these abnormalities can even cause an irregular heartbeat, known as dysrhythmia.

Surprisingly, young athletes or adults can sometimes suffer sudden cardiac death due to these abnormalities, although it’s not very common. The most common cause of sudden death in these individuals is a condition known as hypertrophic cardiomyopathy, where the heart muscle becomes abnormally thick, leading to life-threatening irregular heartbeats (ventricular dysrhythmias).

What to expect with Coronary Artery Anomalies

Most irregularities aren’t usually significant, meaning the majority of patients have a good outlook. However, those with anomalies causing reduced blood flow should seek out medical centers experienced in managing these conditions.

Possible Complications When Diagnosed with Coronary Artery Anomalies

Most abnormalities and variants in the coronary artery don’t significantly affect blood flow and are usually spotted by chance during a Cardiac CT Angiogram (CCTA). Nonetheless, if these anomalies do limit blood flow, they can lead to symptoms of reduced blood supply to the heart. These symptoms could include chest pain, difficulty breathing, and even sudden death. Specific coronary artery abnormalities like ALCAPA and coronary artery fistula may become apparent in young infants. Infants with these conditions may struggle to gain weight and grow as expected, experience chest pain when crying or eating, and show signs such as excessive sweating, difficulty in breathing, and a pale complexion.