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Basic Information ⬇

AUTHORS: Vasken Keleshian, MD and Pranav M. Patel, MD, FACC, FAHA, FSCAI

Definition

Carotid artery aneurysm is a localized enlargement of the carotid artery caused by weakening of the artery wall and is categorized as either a true or false aneurysm. True aneurysm involves the full thickness of the arterial wall and has >50% increase in vessel diameter compared to the expected normal. False aneurysm, also known as pseudoaneurysm, forms due to disruption or injury to the artery wall that results in a contained hematoma connecting with the inner artery lumen.

Synonyms

Aneurysm of artery of neck

Aneurysm of common carotid artery

Aneurysm of external carotid artery

Aneurysm of internal carotid artery

ICD-10 CM CODES
I72.0Aneurysm of carotid artery
I67.1Cerebral aneurysm, non-ruptured
Epidemiology & Demographics
INCIDENCE

Aneurysms of the carotid artery are rare. It is estimated that 0.1% to 2% of all carotid procedures are performed for correction of aneurysmal disease.1 It accounts for 0.4% to 4% of all aneurysms in the peripheral arteries.2

PEAK INCIDENCE

Not known

PREVALENCE

Overall, carotid artery aneurysm accounts for <1% of all arterial aneurysms and up to 4% of aneurysms in the peripheral arteries.3

PREDOMINANT SEX & AGE

Most patients are male, and most are diagnosed in the sixth or seventh decade of life.3

GENETICS

Genetic conditions such as fibromuscular dysplasia, connective tissue disorders, inflammatory diseases, and congenital defects can cause distortion of the arterial wall and lead to aneurysm.4 If a genetic condition is suspected, further investigation, including obtaining detailed family history, obtaining comprehensive imaging of other vascular beds, and referring for genetic testing, should be considered.

RISK FACTORS

The most common risk factor predisposing to carotid artery aneurysm is atherosclerosis, followed closely by localized infection and prior carotid artery intervention.

Physical Findings & Clinical Presentation

The majority of carotid artery aneurysms are found incidentally on computed tomography (CT) scan or MRI studies. Larger aneurysms can cause cranial nerve deficit, tracheal obstruction, dysphagia, tinnitus, hoarseness, and dizziness.5 Physical examination includes palpation of a pulsatile mass in the neck and auscultation of a carotid artery bruit and can produce an abnormal neurologic examination if a cranial nerve is affected.

Etiology

The most common cause is related to atherosclerosis and infection. Primary infections of the artery wall can lead to true aneurysm, whereas infections related to carotid artery intervention cause secondary infection which predisposes to pseudoaneurysm. Injury from blunt or penetrating trauma can lead to either type of aneurysm depending on the mechanism of arterial wall injury.6 Carotid artery aneurysm can occur as a result of spontaneous dissection, which can occur in setting of radiation exposure (Table E1).7

TABLE E1 Type and Localization of Carotid Artery Aneurysm

Type 1Isolated and short aneurysm of the internal carotid artery above the carotid bulb
Type 2Long aneurysm of the carotid artery extending below the carotid bulb
Type 3Aneurysm of the proximal internal carotid artery and the carotid bifurcation
Type 4Combined aneurysm of the internal and common carotid artery
Type 5Isolated common carotid artery aneurysm

Diagnosis ⬆ ⬇

Differential Diagnosis

Finding of a palpable neck mass should prompt an evaluation for potential causes, including enlarged lymph nodes, cystic hygroma, neoplastic process of the neck, peritonsillar abscess, and branchial cleft cyst.

Workup

Workup should include ultrasound imaging as the initial test of choice for evaluation of palpable neck mass. Laboratory tests targeting infection and/or inflammation can be helpful in ruling out alternative diagnoses and identify contributing systemic syndromes.

Laboratory Test (S)

Although there are no specific diagnostic laboratories for detecting carotid artery aneurysm, certain laboratory tests can help rule out alternative diagnoses. Inflammatory markers such as erythrocyte sedimentation rate, C-reactive protein, and white blood count can be helpful in identifying coexisting inflammatory or infectious syndromes that can contribute to aneurysm formation.

Imaging Studies

Gold standard for diagnosis includes demonstration of an aneurysm on imaging. Ultrasound can be the initial test of choice, and if further spacial resolution is needed to define the aneurysm, computed tomography angiography (CTA) (Fig. E1) or magnetic resonance angiography (MRA) can be used. Given the high spacial resolution of CTA and MRA, they have largely replaced invasive angiography for diagnostic purposes.

Figure E1 Coronal computed tomography angiography of carotid artery aneurysm.

(A) Left intracranial internal carotid artery supraclinoid laterally projecting 2 mm saccular aneurysm with 2 mm neck. (B) Left distal cervical internal carotid artery medially projecting pseudoaneurysm.

Treatment ⬆ ⬇

Nonpharmacologic Therapy

Treatment of carotid artery aneurysm depends on the presence of symptoms (transient ischemic attack, stroke, mass effect, bleeding), presence of thrombus, or luminal diameter (Fig. E2).

Figure E2 Approach to Management of Carotid Artery Aneurysm and Indication for Repair

TIA, Transient Ischemic Attack.

!!flowchart!!

Acute General Rx

Open surgical repair is pursued for acute management of carotid artery aneurysm. Rapidly expanding aneurysm or ruptured aneurysm needs immediate surgical control of hemorrhage and protection of the airway.

Chronic Rx

Nonoperative management includes observation with serial imaging every 6 to 12 mo. If operative management is pursued, repair can occur either endovascular stenting or open surgical repair. Decision for the type of repair depends on center experience.

Disposition

Carotid artery aneurysm is associated with low mortality rates. Single center experiences have shown mortality of as low as 0% to as high as 5%. Longitudinal medical management includes using antiplatelet therapy, anticoagulation, and serial imaging.

Referral

If carotid artery aneurysm is detected on imaging, vascular surgery or endovascular specialist should be consulted for further management and treatment.

Pearls & Considerations ⬆ ⬇

Comments

Carotid artery aneurysm is associated with carotid artery atherosclerosis or localized infection, or it can result from prior carotid intervention. Diagnosis is made using imaging modalities including ultrasound, CTA, or MRA. Treatment involves nonoperative management for small (<2 cm) and asymptomatic aneurysms, which includes antiplatelet therapy, anticoagulation, blood pressure control, and serial imaging. Symptomatic, large, or thrombotic aneurysm can be treated surgically with either open vascular surgery or endovascular repair.

Prevention

Cornerstone of prevention involves modifying risk factors that are associated with development of atherosclerosis.

Related Content

Fibromuscular dysplasia (Related Key Topic)

Renal artery stenosis (Related Key Topic)

Intracranial aneurysm (Related Key Topic)

Related Content ⬆

  1. Kramer C.K., Zhou W. : Carotid aneurysm reviewInt J Angiol. ;28:17-19, 2019.
  2. Fankhauser GT et al: Surgical and medical management of extracranial carotid artery aneurysms, J Vasc Surg 61(2):389-389, 2014.
  3. El-Sabrout R., Cooley D.A. : Extracranial carotid artery aneurysms: Texas Heart Institute experienceJ Vasc Surg. ;31(4):702-712, 2000.
  4. McCready R.A. : Endoluminal repair of carotid artery pseudoaneurysms: a word of cautionJ Vasc Surg. ;40(5), 2004.
  5. Mokri B. : Extracranial internal carotid artery aneurysmsMayo Clin Proc. ;57(5), 1982.
  6. Garg K. : Presentation and management of carotid artery aneurysms and pseudoaneurysmsJ Vasc Surg. ;55(6):1618-1622, 2012.
  7. Xu J., Cao Y. : Radiation-induced carotid artery stenosis: a comprehensive review of the literatureInterv Neurol. ;2(4), 2014.