Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis.

Signs and symptoms

The common carotid artery is the large artery whose pulse can be felt on both sides of the neck under the jaw. On the right side it starts from the brachiocephalic artery (a branch of the aorta), and on the left side the artery comes directly off the

aortic arch The aortic arch, arch of the aorta, or transverse aortic arch () is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea. Structure The aorta begins ...

. At the throat it forks into the

internal carotid artery The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these ...

and the

external carotid artery The external carotid artery is a major artery of the head and neck. It arises from the common carotid artery when it splits into the external and internal carotid artery. External carotid artery supplies blood to the face and neck. Structure T ...

. The internal carotid artery supplies the

brain A brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as Visual perception, vision. I ...

, and the external carotid artery supplies the face. This fork is a common site for atherosclerosis, an inflammatory build-up of

atheromatous An atheroma, or atheromatous plaque, is an abnormal and reversible accumulation of material in the inner layer of an arterial wall. The material consists of mostly macrophage cells, or debris, containing lipids, calcium and a variable amount o ...

plaque inside the common carotid artery, or the internal carotid arteries that causes them to narrow. The plaque can be stable and asymptomatic, or it can be a source of embolization.

Emboli An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus may be a blood clot (thrombus), a fat globule ( fat embolism), a bubble of air or other gas ( gas embolism), amniotic fluid ( amn ...

break off from the plaque and travel through the circulation to blood vessels in the brain. As the vessels get smaller, an embolus can lodge in the vessel wall and restrict the blood flow to parts of the brain. This

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems w ...

can either be temporary, yielding a transient ischemic attack (TIA), or permanent resulting in a thromboembolic

stroke A stroke is a disease, medical condition in which poor cerebral circulation, blood flow to the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorr ...

. Transient ischemic attacks are a warning sign and may be followed by severe permanent strokes, particularly within the first two days. TIAs by definition last less than 24 hours and frequently take the form of weakness or loss of sensation of a limb or the trunk on one side of the body or the loss of sight ( amaurosis fugax) in one eye. Less common symptoms are artery sounds (

bruit Bruit, also called vascular murmur, is the abnormal sound generated by turbulent flow of blood in an artery due to either an area of partial obstruction or a localized high rate of blood flow through an unobstructed artery. The bruit may be hea ...

s), or ringing in the ears ( tinnitus). In asymptomatic individuals with a carotid stenosis, the risk of developing a stroke is increased above those without a stenosis. The risk of stroke is possibly related to the degree of stenosis on imaging. Some studies have found an increased risk with increasing degrees of stenosis while other studies have not been able to find such a relationship.

Pathophysiology

Atherosclerosis causes plaque to form within the carotid artery walls, usually at the fork where the common carotid artery divides into the internal and external carotid artery. The plaque build-up can narrow or constrict the artery lumen, a condition called

stenosis A stenosis (from Ancient Greek στενός, "narrow") is an abnormal narrowing in a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture). ''Stricture'' ...

. Rupture of the plaque can release atherosclerotic debris or blood clots into the artery. A piece of this material can break off and travel ( embolize) up through the internal carotid artery into the brain, where it blocks circulation, and can cause death of the brain tissue, a condition referred to as ischemic

. Sometimes the

causes temporary symptoms first, known as TIAs, where temporary ischemia occurs in the

, or

retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which the ...

without causing an

infarction Infarction is tissue death ( necrosis) due to inadequate blood supply to the affected area. It may be caused by artery blockages, rupture, mechanical compression, or vasoconstriction. The resulting lesion is referred to as an infarct (from th ...

. Symptomatic

has a high risk of stroke within the next 2 days.

National Institute for Health and Clinical Excellence The National Institute for Health and Care Excellence (NICE) is an executive non-departmental public body of the Department of Health and Social Care in England that publishes guidelines in four areas: * the use of health technologies withi ...

(NICE) guidelines recommend that people with moderate to severe (50–99% blockage) stenosis, and symptoms, should have "urgent" endarterectomy within 2 weeks. When the plaque does not cause symptoms, people are still at higher risk of stroke than the general population, but not as high as people with symptomatic stenosis. The incidence of stroke, including fatal stroke, is 1–2% per year. The surgical mortality of endarterectomy ranges from 1–2% to as much as 10%. Two large randomized clinical trials have demonstrated that carotid surgery done with a 30-day stroke and death risk of 3% or less will benefit asymptomatic people with ≥60% stenosis who are expected to live at least 5 years after surgery. Surgeons are divided over whether asymptomatic people should be treated with medication alone or should have surgery. The common carotid artery is the large vertical artery in red. The blood supply to the carotid artery starts at the arch of the aorta (bottom). The carotid artery divides into the

and the

. The internal carotid artery supplies the brain. Plaque often builds up at that division and causes a narrowing (stenosis). Pieces of plaque can break off and block the small arteries above in the brain, which causes a

. Plaque can also build up at the origin of the carotid artery at the aorta. File:Gray513.png,

Carotid arteries In anatomy, the left and right common carotid arteries (carotids) (Entry "carotid"
in
common carotid artery(bottom), and divides into the

(left) and

(right). The atherosclerotic plaque is the dark mass on the left

Diagnosis

Carotid artery stenosis is usually diagnosed by color flow duplex ultrasound scan of the carotid arteries in the neck. This involves no radiation, no needles and no contrast agents that may cause

allergic Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic der ...

reactions. This test has good

sensitivity and specificity ''Sensitivity'' and ''specificity'' mathematically describe the accuracy of a test which reports the presence or absence of a condition. Individuals for which the condition is satisfied are considered "positive" and those for which it is not are ...

. Typically duplex ultrasound scan is the only investigation required for decision making in carotid stenosis as it is widely available and rapidly performed. However, further imaging can be required if the stenosis is not near the bifurcation of the carotid artery. One of several different imaging modalities, such as a computed tomography angiogram (CTA) or magnetic resonance angiogram (MRA) may be useful. Each imaging modality has its advantages and disadvantages - Magnetic resonance angiography and CT angiography with contrast is contraindicated in patients with

chronic kidney disease Chronic kidney disease (CKD) is a type of kidney disease in which a gradual loss of kidney function occurs over a period of months to years. Initially generally no symptoms are seen, but later symptoms may include leg swelling, feeling tired, vo ...

, catheter angiography has a 0.5% to 1.0% risk of stroke, MI, arterial injury or retroperitoneal bleeding. The investigation chosen will depend on the clinical question and the imaging expertise, experience and equipment available. For purpose of treatment, the degree of carotid stenosis is defined as: : percent stenosis = ( 1 − ( minimum diameter within stenosis) / ( poststenotic diameter ) ) × 100%.

Screening

The

U.S. Preventive Services Task Force The United States Preventive Services Task Force (USPSTF) is "an independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services". ...

(USPSTF) recommends against routine

screening Screening may refer to: * Screening cultures, a type a medical test that is done to find an infection * Screening (economics), a strategy of combating adverse selection (includes sorting resumes to select employees) * Screening (environmental), ...

for carotid artery stenosis in those without symptoms as of 2021. While routine population screening is not advised, the

American Heart Association The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate cardiac care in an effort to reduce disability and deat ...

and the Society for Vascular Surgery recommend screening in those diagnosed with related medical conditions or have risk factors for carotid artery disease. Screening is recommended for people who have: * Vascular disease elsewhere in the body, including: **

Peripheral artery disease Peripheral artery disease (PAD) is an abnormal narrowing of arteries other than those that supply the heart or brain. When narrowing occurs in the heart, it is called coronary artery disease, and in the brain, it is called cerebrovascular dis ...

(PAD) **

Coronary artery disease Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves the reduction of blood flow to the heart muscle due to build-up of atherosclerotic pl ...

(CAD) ** Atherosclerotic aortic aneurysm (AAA) * Two or more of the following risk factors: ** High blood pressure (

hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high b ...

) ** High cholesterol (

hyperlipidemia Hyperlipidemia is abnormally elevated levels of any or all lipids (fats, cholesterol, or triglycerides) or lipoproteins in the blood. citing: and The term ''hyperlipidemia'' refers to the laboratory finding itself and is also used as an umbre ...

) ** Tobacco smoking ** Family history – First-degree relative diagnosed with atherosclerosis before age 60 or who had an ischemic

The American Heart Association also recommends screening if a physician detects a carotid bruit, or murmur, over the carotid artery by listening through a stethoscope during a physical exam. For people with symptoms, the American Heart Association recommends initial screening using ultrasound.

Treatment

The goal of treating carotid artery stenosis is to reduce the risk of stroke. The type of treatment depends on the severity of the disease and includes: * Lifestyle modifications including smoking cessation, eating a healthy diet and reducing sodium intake, losing weight, and exercising regularly. * Medications to control high blood pressure and high levels of lipids in the blood. * Surgical intervention for carotid artery revascularization.

Medication

Clinical guidelines (such as those of the American Heart Association (AHA) and National Institute for Clinical Excellence (NICE)) recommend that all patients with carotid stenosis be given medications to control their vascular risk factors, usually blood pressure lowering medications (if they have hypertension), diabetes medication (if they have diabetes), and recommend exercise, weight reduction (if overweight) and smoking cessation (for smokers). In addition, they would benefit from anti-platelet medications (such as

aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...

clopidogrel Clopidogrel — sold under the brand name Plavix, among others — is an antiplatelet medication used to reduce the risk of heart disease and stroke in those at high risk. It is also used together with aspirin in heart attacks and following ...

) and cholesterol lowering medication (such as

statins Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low ...

, which were originally prescribed for their cholesterol-lowering effects but were also found to reduce inflammation and stabilize plaque).

Revascularization

According to the American Heart Association, interventions beyond medical management is based upon whether patients have symptoms: * Asymptomatic patients: assessment of other medical conditions, life expectancy, and other individual factors; evaluation of the risks versus benefits; and patient preference are considered when determining whether surgical intervention should be performed. * Symptomatic patients: it is recommended that patients who have experienced a transient ischemic attack or non-severely disabling acute ischemic stroke undergo surgical intervention, if possible. All interventions for carotid revascularization ( carotid endarterectomy, carotid stenting, and transcarotid artery revascularization) carry some risk of stroke; however, where the risk of stroke over time from medical management alone is high, intervention may be beneficial.

References

External links

{{Vascular diseases Cerebrovascular diseases Vascular diseases