Carotid Artery Aneurysm

Overview

What is a carotid artery aneurysm?

A carotid artery aneurysm is a bulge in one of your carotid arteries. These arteries supply blood to your brain, head, face and neck. You have a common carotid artery on each side of your upper chest. As it travels up your neck, each common carotid artery divides into two branches. These are your internal carotid artery and external carotid artery. Aneurysms may affect any of your carotid arteries. But they usually develop in one of your internal carotid arteries.

An aneurysm happens when part of an artery wall weakens. As the aneurysm grows bigger, your artery wall grows thinner. There’s an increased risk that the aneurysm will burst. You can compare this to a balloon filling up with air. As the balloon gets bigger, its walls get thinner and may pop. So, the larger an aneurysm grows, the more dangerous it can be.

How serious is a carotid artery aneurysm?

Carotid artery aneurysms affect blood vessels that send blood to your brain. These aneurysms may be small and cause no complications. But blood clots can sometimes form in the aneurysm and block blood flow to your brain. This can lead to a transient ischemic attack (TIA) (mini stroke) or ischemic stroke. Large aneurysms may rupture (burst), leading to a hemorrhagic stroke and life-threatening bleeding.

What is a true vs. false carotid artery aneurysm?

Like other aneurysms, carotid artery aneurysms can be either true or false. These are medical terms that describe how the bulge forms in your artery. A true carotid artery aneurysm affects all three layers of your artery wall. These three layers (intima, media and adventitia) all bulge outward and form the aneurysm’s wall. Atherosclerosis is the most common cause of a true aneurysm.

A false carotid artery aneurysm is also called a pseudoaneurysm. A pseudoaneurysm only affects one or two layers of your artery wall. It usually looks like a round sac that sticks out of your artery on a narrow “neck.” Trauma, infection and complications from medical procedures are typical causes of a pseudoaneurysm.

Both true and false aneurysms can lead to complications and may require treatment.

Who do carotid artery aneurysms affect?

Carotid artery aneurysms can affect adults of any age and, rarely, children. But they usually affect people in their 50s or 60s.

Are carotid artery aneurysms common?

Carotid artery aneurysms are rare. Fewer than 1 in 100 aneurysms are carotid artery aneurysms.

Symptoms and Causes

What are the symptoms of a carotid artery aneurysm?

Some people with carotid artery aneurysms have no symptoms. Of those who do, symptoms of a transient ischemic attack (TIA) or stroke are most common. A TIA is also called a “mini stroke,” and it may be a warning sign that a stroke may happen in the next few days or weeks. Both TIAs and strokes happen when blood flow to your brain is interrupted.

TIAs and strokes are medical emergencies that need immediate care. Call 911 or your local emergency number if you have any of the following symptoms:

  • Difficulty seeing from one or both eyes.
  • Difficulty walking.
  • Dizziness, loss of coordination or feeling off-balance.
  • Numbness or weakness in your face, arms or legs, especially on one side of your body.
  • Sudden, severe headache.
  • Trouble speaking or understanding others’ speech. Your speech may be slurred or confused.

You may not be able to call 911 if you’re experiencing severe symptoms. So, it’s important to educate your loved ones about TIA and stroke symptoms so they know when to call for help. If you live alone, it’s a good idea to get a medical alert system that requires simply pushing a button to seek help.

Aside from TIAs and strokes, the aneurysm may cause you to feel other symptoms if it puts pressure on nearby structures. If the aneurysm presses on veins or nerves in your neck or head, you may experience:

Call your healthcare provider if you have any of these symptoms.

What causes carotid artery aneurysms?

There are many possible causes of carotid artery aneurysms, including:

What are the risk factors for carotid artery aneurysms?

Carotid artery aneurysms happen when your artery’s walls become weak. Many factors can raise your risk of weakened arterial walls, including:

Diagnosis and Tests

How is a carotid artery aneurysm diagnosed?

Healthcare providers diagnose carotid artery aneurysms through:

  • A physical exam. This includes using a stethoscope to hear blood flow through your carotid artery. A whooshing sound (carotid bruit) is sometimes a sign of a carotid artery aneurysm.
  • Family history. Your provider will ask about medical conditions that have affected your biological family. People with a family history of aneurysms often face a higher risk.
  • Medical history. Your provider will learn about your medical history and associated conditions. This helps your provider identify possible causes of an aneurysm.
  • Imaging tests. Imaging tests show what’s happening inside of your carotid artery and the surrounding areas. They confirm the diagnosis of a carotid artery aneurysm and help your provider determine the best treatment.

Sometimes, providers diagnose aneurysms after suspecting a person has one. Other times, they diagnose them through imaging tests done for other reasons. This is called an incidental diagnosis.

What tests diagnose carotid artery aneurysms?

Imaging tests that diagnose carotid artery aneurysms include:

Your provider may also recommend:

  • Brain imaging to check blood flow through your brain and look for additional aneurysms.
  • Genetic testing to check for underlying genetic conditions.
  • Imaging tests to check your aorta or other arteries for additional aneurysms.

Management and Treatment

What is the treatment for carotid artery aneurysms?

Carotid artery aneurysm treatment includes:

  • Surveillance.
  • Open surgery.
  • Endovascular stent grafting.

The goals of treatment are to reduce symptoms and lower your risk of complications. You may need surgical or endovascular repair if you face a high risk of complications like aneurysm rupture or stroke. Your surgeon takes into account many factors to determine your risk, including:

  • Aneurysm size.
  • How quickly the aneurysm is growing.
  • Whether or not you have symptoms.

Surveillance

Also called “watchful waiting,” surveillance means your provider monitors your aneurysm. You’ll have imaging testing (ultrasound, CT or MRI scans) every six to 12 months. Your provider will look for any changes. This is often an option for small aneurysms that aren’t causing any symptoms.

If you have high blood pressure, your provider may prescribe blood pressure medication. This can help lower pressure on the aneurysm. Your provider may also prescribe a cholesterol-lowering medication.

Open surgery

Surgical repair is the traditional treatment method. Your surgeon removes the damaged part of your carotid artery. Then, they create a new path for your blood to flow from the normal artery below the aneurysm to the normal artery above it. This is called bypass grafting.

Your surgeon may use part of a blood vessel taken from somewhere else in your body to create the new blood vessel (graft). Or they may use an artificial material like GORE-TEX®.

Endovascular stent grafting

Endovascular repair is a less invasive option compared to open surgery. You may be eligible for endovascular stent grafting depending on the size of the aneurysm and its location in your carotid artery.

Endovascular means that surgery is performed inside of your artery using long, thin tubes (catheters). Your surgeon makes a small puncture in an artery in your groin. Then, they use catheters to guide a stent graft through your blood vessels until it reaches the aneurysm site. Under X-ray guidance, your surgeon positions the graft in the area of the aneurysm. They expand the graft inside of your artery, where metallic hooks hold it in place. The graft functions as a new path for your blood to flow.

Which treatment is right for me?

Your healthcare provider will tailor treatment to your situation and needs. Before any procedure or surgery, your provider will talk with you about its benefits, risks and side effects. Your provider will also give you detailed guidelines for your preparation and recovery.

Prevention

How can I reduce my risk of a carotid artery aneurysm?

Some risk factors (like biological family history) are out of your control. But you can take some steps to keep your arteries healthy and lower your risk of an aneurysm. These include:

  • Don’t smoke, vape or use tobacco products. Ask your provider for resources to help you quit.
  • Eat a heart-healthy diet low in saturated fat, sodium and sugar.
  • Exercise regularly, according to your healthcare provider’s guidance.
  • Limit your alcohol intake.
  • Manage risk factors like high blood pressure.
  • Take your medications as prescribed.
  • Visit your provider for yearly check-ups and keep all of your follow-up appointments.

Outlook / Prognosis

What can I expect if I have a carotid artery aneurysm?

The outlook for people with carotid artery aneurysms can vary widely. Some people have a small aneurysm that their provider monitors for many years. Others have an aneurysm that grows quickly and needs treatment. Surgeries and endovascular procedures can treat your aneurysm but carry some risks. Talk with your provider about your condition and what you can expect going forward.

Living With

How do I take care of myself?

Follow your healthcare provider’s guidance on lifestyle changes that can help you manage your condition. Also, ask your provider about any activity restrictions. You may need to avoid some activities that cause you to overexert yourself.

When should I see my healthcare provider?

Your provider will tell you how often you need to come in for appointments or testing. Be sure to go to all of your appointments.

Call your provider if you have:

  • New or changing symptoms.
  • Side effects from any of your medications.
  • Any questions or concerns about your aneurysm or your treatment plan.

When should I go to the emergency room?

Call 911 or your local emergency number immediately if you have symptoms of a:

What questions should I ask my doctor?

If you’ve been diagnosed with a carotid artery aneurysm, you probably have many questions. But you might not know where to start. Some questions to begin the conversation include:

  • Where’s the aneurysm located? Is it in my neck or skull?
  • How big is the aneurysm?
  • Will I need treatment? If so, when?
  • What are my treatment options?
  • What are the benefits and risks of each treatment option?
  • What can I expect as I recover?
  • What lifestyle changes should I make?
  • Do I have any activity restrictions?
  • Do I need additional testing? If so, how often?

Frequently Asked Questions

What is the difference between an extracranial carotid artery aneurysm and an intracranial carotid artery aneurysm?

Both terms refer to an aneurysm that affects one of your carotid arteries. But they each describe a different location for where the aneurysm forms. Extracranial means the aneurysm is outside of your skull, in your neck. Intracranial means the aneurysm is within your skull.

Researchers use these two terms because your internal carotid artery travels both outside and within your skull. So, it’s helpful to take a closer look at this artery’s path.

Anatomy of your internal carotid artery

Your internal carotid arteries (one on each side of your neck) branch from your common carotid arteries in your neck. They then travel straight upward through your neck until they reach the base of your skull. This extracranial part of each internal carotid artery is called the C1 or cervical segment. “Cervical” in this context means something related to your neck.

Each internal carotid artery then passes through an opening in your skull called the carotid canal. This is the dividing point between the extracranial and intracranial parts of your artery. After this point, your internal carotid artery is within your skull (intracranial). It continues on a winding path to join up with other blood vessels in your brain. Scientists further divide the intracranial part into six segments:

  • C2: Petrous segment.
  • C3: Lacerum segment.
  • C4: Cavernous segment.
  • C5: Clinoid segment.
  • C6: Ophthalmic segment.
  • C7: Communicating segment.

There’s no need to memorize these terms, but knowing this anatomy can help you talk with your provider about your condition. Your provider may say you have an aneurysm in your “left internal carotid artery, cervical segment.” This refers to the internal carotid artery on the left side of your body, but specifically, a segment outside of your skull.

Ask your provider about any terms you don’t understand. They can help you understand what’s going on inside of your body and where it’s happening.

A note from Cleveland Clinic

Learning you have an aneurysm can feel frightening. You might wonder what caused this to happen and whether your daily life will change. You might also fear complications. But thanks to imaging technologies and treatments, many people can go on with life as normal.

If you’ve been diagnosed with a carotid artery aneurysm, talk with your healthcare provider about next steps for treatment. They may recommend a period of surveillance (keeping an eye on the aneurysm) if the aneurysm is small. Be sure to keep all of your appointments for imaging and follow-ups. And let your provider know if you have any questions or concerns along the way.

Last reviewed by a Cleveland Clinic medical professional on 08/29/2022.

References

  • American Association of Neurological Surgeons. Cerebral Aneurysm. (https://www.aans.org/en/Patients/Neurosurgical-Conditions-and-Treatments/Cerebral-Aneurysm) Accessed 8/29/2022.
  • Galyfos G, Eleftheriou M, Theodoropoulos C, et al. Open versus endovascular repair for extracranial carotid aneurysms. (https://pubmed.ncbi.nlm.nih.gov/33940071/) J Vasc Surg. 2021;74(3):1017-1023.e5. Accessed 8/29/2022.
  • Giannopoulos S, Trinidad E, Aronow H, Soukas P, Armstrong EJ. Εndovascular Repair of Extracranial Carotid Artery Aneurysms: A Systematic Review. (https://pubmed.ncbi.nlm.nih.gov/31894734/) Vasc Endovascular Surg. 2020;54(3):254-263. Accessed 8/29/2022.
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  • Sriamornrattanakul K, Sakarunchai I, Yamashiro K, Yamada Y, Suyama D, Kawase T, Kato Y. Surgical treatment of large and giant cavernous carotid aneurysms. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5532919/) Asian J Neurosurg. 2017 Jul-Sep;12(3):382-388. Accessed 8/29/2022.
  • U.S. National Institutes of Health, National Library of Medicine. Anatomy, Head and Neck, Internal Carotid Arteries. (https://www.ncbi.nlm.nih.gov/books/NBK556061/) Accessed 8/29/2022.
  • Vijaywargiya M, Deopujari R, Athavale SA. Anatomical study of petrous and cavernous parts of internal carotid artery. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5639169/) Anat Cell Biol. 2017 Sep;50(3):163-170. Accessed 8/29/2022.

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