Coronary artery aneurysm (CAA) is an uncommon but serious occurrence that can cause significant complications and even death if untreated.

There are various causes for CAA, and treatment can depend on the underlying cause and associated factors.

This article offers more detail on these types of aneurysms as well as the causes, symptoms, and treatment.

A coronary artery aneurysm (CAA) is when a coronary artery dilates or gets bigger, more than 1.5-fold, compared with nearby usual-sized parts of the artery.

This is a rare occurrence. When it does occur, the right coronary artery is more commonly affected. It is involved in 40% to 70% of CAAs.

CAAs are classified in one of three ways:

  • atherosclerotic
  • inflammatory
  • noninflammatory

In children, Kawasaki disease is the main cause of CAA because of inflammation that results in the coronary arteries if left untreated.

What is Kawasaki disease?

Kawasaki disease is a condition in children that causes tissue swelling in the body. If untreated, it can cause inflammation of the heart and coronary arteries.

It typically affects coronary arteries by weakening their walls. If the artery walls are weakened, as blood goes through the artery, the pressure of the blood causes the artery to bulge, forming something like a blister, which is an aneurysm.

If a blood clot develops in the aneurysm, it can block the artery and cause a heart attack. The aneurysm can also burst, although this is not as common.

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In adults, there are various causes of CAA.

Like in children, Kawasaki disease is one of the top causes of CAAs in adults. It causes inflammation that then causes vasculitis or inflammation of the blood vessels. People with Kawasaki disease require lifelong follow-up and monitoring for cardiac health.

However, the most common cause is atherosclerosis (narrowing of the arteries). This can be caused by high blood pressure, high cholesterol, smoking cigarettes, high triglyceride levels, diabetes, and obesity. There may also be a genetic component in those with coronary artery disease that leads to CAA.

There has also been concern about post-percutaneous coronary interventions (PCIs), especially stent implementations. This may be due to the drugs that prime the arteries, the procedures themselves, or both.

Connective tissue disorders such as Marfan syndrome, Ehlers-Danlos disease, and neurofibromatosis have also been associated with CAAs. Other causes for CAAs also include:

  • infections (bacterial, fungal, syphilitic, Lyme, HIV)
  • drug use (cocaine, protease inhibitors, amphetamines)
  • congenital causes
  • fibromuscular dysplasia (non-atherosclerotic, noninflammatory vascular disease)

Noninflammatory CAAs are typically associated with congenital causes or connective tissue disorders.

In adults, atherosclerosis causes more than 90% of CAAs. In children, Kawasaki disease causes most of the CAAs.

There are often multiple CAAs present.

Inflammatory CAAs are seen more in younger people. For older individuals, atherosclerotic CAAs are more likely to be seen. The atherosclerotic CAAs are often related to hypertension, hyperlipidemia, and smoking cigarettes. Findings often include areas of coronary artery disease as well.

Most times, CAAs have no symptoms. When there are symptoms, they can vary, depending on the underlying cause. When there are symptoms, they are similar to coronary artery disease, including:

Clinically, symptoms can include:

  • myocardial ischemia and infarction or both
  • sudden death

Treatment and management of CAAs can be challenging. The history and causes of these events are mostly unknown.

There is no “optimal” treatment. Individual circumstances must be considered, along with the location of the CAA and the clinical presentation and symptoms.

The most common options for treatment include:

Medications to manage coronary artery aneurysms

Because atherosclerosis is often involved in the development of CAAs in older people, actively treating those risk factors is important. There is debate about prescribing antiplatelet or anticoagulation medications, and there is no current evidence for these drugs.

Your healthcare professional will review your medical records and potential options to medically manage CAA.

Surgical options

The most common surgical procedure is to open the CAA, suture its vessels, and bypass grafting if needed. There is no clinical research on this surgery’s success rate because it’s rarely done.

Surgery is done for those who cannot have a percutaneous intervention, those with obstructive coronary artery disease, or those with large aneurysms at risk of rupturing.

Percutaneous coronary interventions use minimally invasive techniques to help seal off the aneurysm. For this, covered stents are recommended. The stent is placed into the blood vessel, and blood goes through the stent.

The CAA is sealed off from the larger artery so it won’t get bigger or rupture. Eventually, it will shrink.

More research is needed on the long-term outcomes of treatment for CAAs.

Even after CAA treatment, another CAA can occur. The size of CAA at diagnosis may predict the rate of regression, or improvement, with those with a low regression rate for those with large CAA at diagnosis. There is a higher regression rate for those with small CAA at diagnosis.

Overall, the prognosis, especially for small CAAs, is positive, with a low risk of adverse effects. Large CAAs, or those with a diameter of 8mm or more, have a high mortality risk.

Approximately half of those will become obstructed, causing a heart attack or death. CAAs are often associated with other health factors that impact cardiac health, such as atherosclerosis, which may compound any existing issues.

Children who have had CAA because of Kawasaki disease are at risk for cardiac complications for the rest of their lives. They will need lifetime follow-ups with specialists because their risk may increase as they age.

You may need to restrict some activities after a CAA and adopt diet and healthful behaviors or both. You may also need monitoring and check-ups.

Coronary artery aneurysms, or CAAs, are uncommon occurrences but can be serious. They can occur in children and adults, although the causes of CAAs in different age populations differ.

There may not be any symptoms of CAA initially, and they are often found during other cardiac imaging tests or autopsies. Once a CAA is discovered, there are various treatments available. Your healthcare team will review your options and discuss which ones are best for you.