For more information, visit http://www.nhlbi.nih.gov/health/health-topics/topics/catd/

What Causes Carotid Artery Disease?

Carotid artery disease seems to start when damage occurs to the inner layers of the carotid arteries. Major factors that contribute to damage include:

• Smoking
• High levels of certain fats and cholesterol in the blood
• High blood pressure
• High levels of sugar in the blood due to insulin resistance or diabetes

When damage occurs, your body starts a healing process. The healing may cause plaque to build up where the arteries are damaged.

The plaque in an artery can crack or rupture. If this happens, blood cell fragments called platelets will stick to the site of the injury and may clump together to form blood clots.  

The buildup of plaque or blood clots can severely narrow or block the carotid arteries. This limits the flow of oxygen-rich blood to your brain, which can cause a stroke.

Who Is at Risk for Carotid Artery Disease?

Certain traits, conditions, or habits may raise your risk for carotid artery disease. These conditions are known as risk factors. The more risk factors you have, the more likely you are to get the disease. Some risk factors you can control, but others you can't.

The major risk factors for carotid artery disease, listed below, also are the major risk factors for coronary heart disease (also called coronary artery disease) and peripheral arterial disease.

• Unhealthy blood cholesterol levels. This includes high LDL cholesterol (sometimes called “bad” cholesterol) and low HDL cholesterol (sometimes called “good” cholesterol).
• High blood pressure. Blood pressure is considered high if it stays at or above 140/90 mmHg over time. If you have diabetes or chronic kidney disease, high blood pressure is defined as 130/80 mmHg or higher. (The mmHg is millimeters of mercury—the units used to measure blood pressure.)
• Smoking. Smoking can damage and tighten blood vessels, lead to unhealthy cholesterol levels, and raise blood pressure. Smoking also can limit how much oxygen reaches the body's tissues.
• Insulin resistance. This condition occurs if the body can't use its own insulin properly. Insulin is a hormone that helps move blood sugar into cells where it's used as an energy source. Insulin resistance may lead to diabetes.
• Diabetes. With this disease, the body's blood sugar level is too high because the body doesn't make enough insulin or doesn't use its insulin properly. People who have diabetes are four times more likely to have carotid artery disease than people who don't have diabetes.
• Overweight or obesity. The terms "overweight" and "obesity" refer to body weight that's greater than what is considered healthy for a certain height.
• Metabolic syndrome. Metabolic syndrome is the name for a group of risk factors that raise your risk for stroke and other health problems, such as diabetes and heart disease. The five metabolic risk factors are a large waistline (abdominal obesity), a high triglyceride (tri-GLIS-er-ide) level (a type of fat found in the blood), a low HDL cholesterol level, high blood pressure, and high blood sugar. Metabolic syndrome is diagnosed if you have at least three of these metabolic risk factors.
• Lack of physical activity. Lack of physical activity can worsen some other risk factors for carotid artery disease, such as unhealthy blood cholesterol levels, high blood pressure, diabetes, and overweight or obesity.
• Unhealthy diet. An unhealthy diet can raise your risk for carotid artery disease. Foods that are high in saturated and trans fats, cholesterol, sodium (salt), and sugar can worsen other carotid artery disease risk factors.
• Older age. As you get older, your risk for carotid artery disease increases. Genetic or lifestyle factors cause plaque to build up in your arteries as you age. Before age 75, the risk is greater in men than women. However, after age 75, the risk is greater in women.
• Family history of atherosclerosis.

Having any of these risk factors doesn't guarantee that you'll develop carotid artery disease. However, if you know that you have one or more risk factors, you can take steps to help prevent or delay the disease.

Steps include following a healthy lifestyle and taking medicines as your doctor prescribes. (For more information, go to “How Can Carotid Artery Disease Be Prevented?”)

If you have plaque buildup in your carotid arteries, you also may have plaque buildup in other arteries. People who have carotid artery disease also are at increased risk for coronary heart disease.

What Are the Signs and Symptoms of Carotid Artery Disease?

Carotid artery disease may not cause signs or symptoms until it severely narrows or blocks a carotid artery. Signs and symptoms may include a bruit (broo-E), a transient ischemic attack (TIA), or a stroke.

Bruit

During a physical exam, your doctor may listen to your carotid arteries with a stethoscope. He or she may hear a whooshing sound called a bruit. This sound may suggest changed or reduced blood flow due to plaque buildup. To find out more, your doctor may recommend tests.

Not all people who have carotid artery disease have bruits.

Transient Ischemic Attack (Mini-Stroke)

For some people, having a TIA, or “mini-stroke,” is the first sign of carotid artery disease. During a mini-stroke, you may have some or all of the symptoms of a stroke. However, the symptoms usually go away on their own within 24 hours.

The symptoms may include:

• Sudden weakness or numbness in the face or limbs, often on just one side of the body
• The inability to move one or more of your limbs
• Trouble speaking or understanding speech
• Sudden trouble seeing in one or both eyes
• Dizziness or loss of balance
• A sudden, severe headache with no known cause

Even if the symptoms stop quickly, you should see a doctor right away. Call 9–1–1 for help. Do not drive yourself to the hospital. It's important to get checked and to get treatment started as soon as possible.

A mini-stroke is a warning sign that you're at high risk of having a stroke. You shouldn't ignore these symptoms. About one-third of people who have mini-strokes will later have strokes. Getting medical care can help find possible causes of a mini-stroke and help you manage risk factors. These actions might prevent a future stroke.

Although a mini-stroke may warn of a stroke, it doesn't predict when a stroke will happen. A stroke may occur days, weeks, or even months after a mini-stroke. In about half of the cases of strokes that follow TIAs, the strokes occur within 1 year.

Stroke

The symptoms of a stroke are the same as those of a mini-stroke, but the results are not. A stroke can cause lasting brain damage; long-term disability, such as vision or speech problems or paralysis (an inability to move); or death. Most people who have strokes have not previously had warning mini-strokes.

Getting treatment for a stroke right away is very important. You have the best chance for full recovery if treatment to open a blocked artery is given within 4 hours of symptom onset. The sooner treatment occurs, the better your chances of recovery.

Call 9–1–1 for help as soon as symptoms occur. Do not drive yourself to the hospital. It's very important to get checked and to get treatment started as soon as possible.

Make those close to you aware of stroke symptoms and the need for urgent action. Learning the signs and symptoms of a stroke will allow you to help yourself or someone close to you lower the risk of brain damage or death due to a stroke.

How Is Carotid Artery Disease Diagnosed?

Your doctor will diagnose carotid artery disease based on your medical history, a physical exam, and test results.

Medical History

Your doctor will find out whether you have any of the major risk factors for carotid artery disease. He or she also will ask whether you've had any signs or symptoms of a mini-stroke or stroke.

Physical Exam

To check your carotid arteries, your doctor will listen to them with a stethoscope. He or she will listen for a whooshing sound called a bruit. This sound may indicate changed or reduced blood flow due to plaque buildup. To find out more, your doctor may recommend tests.

Diagnostic Tests

The following tests are common for diagnosing carotid artery disease. If you have symptoms of a mini-stroke or stroke, your doctor may use other tests as well.

Carotid Ultrasound

Carotid ultrasound (also called sonography) is the most common test for diagnosing carotid artery disease. It's a painless, harmless test that uses sound waves to create pictures of the insides of your carotid arteries. This test can show whether plaque has narrowed your carotid arteries and how narrow they are.

A standard carotid ultrasound shows the structure of your carotid arteries. A Doppler carotid ultrasound shows how blood moves through your carotid arteries.

Carotid Angiography

Carotid angiography (an-jee-OG-ra-fee) is a special type of x ray. This test may be used if the ultrasound results are unclear or don't give your doctor enough information.

For this test, your doctor will inject a substance (called contrast dye) into a vein, most often in your leg. The dye travels to your carotid arteries and highlights them on x-ray pictures.

Magnetic Resonance Angiography

Magnetic resonance angiography (MRA) uses a large magnet and radio waves to take pictures of your carotid arteries. Your doctor can see these pictures on a computer screen.

For this test, your doctor may give you contrast dye to highlight your carotid arteries on the pictures.

Computed Tomography Angiography

Computed tomography (to-MOG-rah-fee) angiography, or CT angiography, takes x-ray pictures of the body from many angles. A computer combines the pictures into two- and three-dimensional images.

For this test, your doctor may give you contrast dye to highlight your carotid arteries on the pictures.

How Is Carotid Artery Disease Treated?

Treatments for carotid artery disease may include lifestyle changes, medicines, and medical procedures. The goals of treatment are to stop the disease from getting worse and to prevent a stroke.

Your treatment will depend on your symptoms, how severe the disease is, and your age and overall health.

Lifestyle Changes

Making lifestyle changes can help prevent carotid artery disease or keep it from getting worse. For some people, these changes may be the only treatment needed:

• Follow a healthy diet to prevent or lower high blood pressure and high blood cholesterol and to maintain a healthy weight.
• Be physically active. Check with your doctor first to find out how much and what kinds of activity are safe for you.
• If you're overweight or obese, lose weight.
• If you smoke, quit. Also, try to avoid secondhand smoke.

Follow a Healthy Diet

A healthy diet is an important part of a healthy lifestyle. Following a healthy diet can prevent or reduce high blood pressure and high blood cholesterol and help you maintain a healthy weight.

For information about healthy eating, go to the National Heart, Lung, and Blood Institute's (NHLBI's) Aim for a Healthy Weight Web site. This site provides practical tips on healthy eating, physical activity, and controlling your weight.

Therapeutic Lifestyle Changes (TLC). Your doctor may recommend a three-part program called TLC if you have high blood cholesterol. TLC includes a healthy diet, physical activity, and weight management.

With the TLC diet, less than 7 percent of your daily calories should come from saturated fat. This kind of fat is found mainly in meat, poultry, and dairy products. No more than 25 to 35 percent of your daily calories should come from all fats, including saturated, trans, monounsaturated, and polyunsaturated fats.

You also should have less than 200 mg a day of cholesterol. The amounts of cholesterol and the different kinds of fat in prepared foods can be found on the foods' Nutrition Facts labels.

Foods high in soluble fiber also are part of a healthy diet. They help block the digestive tract from absorbing cholesterol. These foods include:

• Whole-grain cereals such as oatmeal and oat bran
• Fruits such as apples, bananas, oranges, pears, and prunes
• Legumes such as kidney beans, lentils, chick peas, black-eyed peas, and lima beans

A diet rich in fruits and vegetables can increase important cholesterol-lowering compounds in your diet. These compounds, called plant stanols or sterols, work like soluble fiber.

Fish are an important part of a healthy diet. They're a good source of omega-3 fatty acids, which help lower blood cholesterol levels. Try to have about two fish meals every week. Fish high in omega-3 fatty acids are salmon, tuna (canned or fresh), and mackerel.

You also should try to limit the amount of sodium (salt) that you eat. Too much sodium can raise your risk of high blood pressure. Choose low-sodium and "no added salt" foods and seasonings at the table or when cooking. The Nutrition Facts label on food packaging shows the amount of sodium in an item.

Try to limit drinks with alcohol. Too much alcohol will raise your blood pressure and triglyceride level. (Triglycerides are a type of fat found in the blood.) Alcohol also adds extra calories, which will cause weight gain.

Men should have no more than two drinks containing alcohol a day. Women should have no more than one drink containing alcohol a day. One drink is a glass of wine, beer, or a small amount of hard liquor.

For more information about TLC, go to the NHLBI's “Your Guide to Lowering Your Cholesterol With TLC.”

Dietary Approaches to Stop Hypertension (DASH). Your doctor may recommend the DASH eating plan if you have high blood pressure. The DASH eating plan focuses on fruits, vegetables, whole grains, and other foods that are heart healthy and low in fat, cholesterol, and sodium.

DASH also focuses on fat-free or low-fat milk and dairy products, fish, poultry, and nuts. The DASH eating plan is reduced in red meats (including lean red meats), sweets, added sugars, and sugar-containing beverages. It's rich in nutrients, protein, and fiber.

The DASH eating plan is a good healthy eating plan, even for those who don't have high blood pressure. For more information, go to the NHLBI's "Your Guide to Lowering Your Blood Pressure With DASH."

Be Physically Active

Regular physical activity can lower many carotid artery disease risk factors, including LDL ("bad") cholesterol, high blood pressure, and excess weight.

Physical activity also can lower your risk for diabetes and raise your HDL cholesterol level. HDL cholesterol is the “good” cholesterol that helps prevent plaque buildup.

Talk with your doctor before you start a new exercise plan. Ask him or her how much and what kinds of physical activity are safe for you.

People gain health benefits from as little as 60 minutes of moderate-intensity aerobic activity per week. The more active you are, the more you will benefit.

For more information about physical activity, go to the U.S. Department of Health and Human Services' "2008 Physical Activity Guidelines for Americans," the Health Topics Physical Activity and Your Heart article, and the NHLBI's "Your Guide to Physical Activity and Your Heart."

Although the Health Topics article and “Your Guide” booklet focus on heart health, they include information that applies to general health and well-being.

Maintain a Healthy Weight

Maintaining a healthy weight can lower your risk for carotid artery disease and stroke. Even a modest weight gain can increase your risk of having a stroke.

If you're overweight, aim to reduce your weight by 7 to 10 percent during your first year of treatment. This amount of weight loss can lower your risk for carotid artery disease and other health problems.

After the first year, you may have to continue to lose weight so you can lower your body mass index (BMI) to less than 25.

BMI measures your weight in relation to your height. A BMI between 25 and 29.9 is considered overweight for adults. A BMI of 30 or more is considered obese for adults. A BMI of less than 25 is the goal for preventing and treating carotid artery disease.

You can measure your BMI using the NHLBI's online calculator, or your health care provider can measure your BMI.

For more information about losing weight or maintaining a healthy weight, go to the Health Topics Overweight and Obesity article.

Quit Smoking

If you smoke or use tobacco, quit. Smoking can damage your arteries and raise your risk for stroke and other health problems. Also, try to avoid secondhand smoke.

Talk with your doctor about programs and products that can help you quit. For more information about how to quit smoking, go to the Health Topics Smoking and Your Heart article and the NHLBI's "Your Guide to a Healthy Heart." Although these resources focus on heart health, they include general information about how to quit smoking.

The U.S. Department of Health and Human Services also has information about how to quit smoking.

Medicines

You may need medicines to treat diseases and conditions that damage the carotid arteries. High blood pressure, high blood cholesterol, and diabetes can worsen carotid artery disease.

Some people can control these risk factors with lifestyle changes. Others also need medicines to achieve and maintain control.

You may need anticlotting medicines to prevent blood clots from forming in your carotid arteries and causing a stroke. Damage and plaque buildup make blood clots more likely.

Aspirin and clopidogrel are two common anticlotting medicines. They stop platelets from clumping together to form clots. These medicines are a mainstay of treatment for people who have known carotid artery disease.

Your health care team will help find a treatment plan that's right for you. Sticking to this plan will help avoid further harm to your carotid arteries.

If you have a stroke due to a blood clot, you may be given a clot-dissolving, or clot-busting, medicine. This type of medicine must be given within 4 hours of symptom onset.

The sooner treatment occurs, the better your chances of recovery. Thus, it's important to know the signs and symptoms of a stroke and call 9–1–1 right away for emergency care.

Medical Procedures

You may need a medical procedure to treat carotid artery disease. Doctors use one of two methods to open narrowed or blocked carotid arteries: carotid endarterectomy (END-ar-ter-EK-to-me) and carotid artery angioplasty and stenting.

Carotid Endarterectomy

Carotid endarterectomy is mainly for people whose carotid arteries are blocked 50 percent or more.

For the procedure, a surgeon will make a cut in your neck to reach the narrowed or blocked carotid artery. Next, your surgeon will make a cut in the blocked part of the artery and remove the artery's inner lining.

Finally, your surgeon will close the artery with stitches and stop any bleeding. He or she will then close the cut in your neck.

Carotid Endarterectomy

The illustration shows the process of carotid endarterectomy. Figure A shows a carotid artery that has plaque buildup. The inset image shows a cross-section of the narrowed carotid artery. Figure B shows how the carotid artery is cut and the plaque removed. Figure C shows the artery stitched up and normal blood flow restored. The inset image shows a cross-section of the artery with plaque removed and normal blood flow restored.

Carotid Artery Angioplasty and Stenting

Doctors use a procedure called angioplasty (AN-jee-oh-plas-tee) to widen the carotid arteries and restore blood flow to the brain.

A thin tube with a deflated balloon on the end is threaded through a blood vessel in your neck to the narrowed or blocked carotid artery. Once in place, the balloon is inflated to push the plaque outward against the wall of the artery.

A stent (a small mesh tube) is then put in the artery to support the inner artery wall. The stent also helps prevent the artery from becoming narrowed or blocked again.

Carotid Artery Stenting

The illustration shows the process of carotid artery stenting. Figure A shows an internal carotid artery that has plaque buildup and reduced blood flow. The inset image shows a cross-section of the narrowed carotid artery. Figure B shows a stent being placed in the carotid artery to support the inner artery wall and keep the artery open. Figure C shows normal blood flow restored in the stent-widened artery. The inset image shows a cross-section of the stent-widened artery.

How Can Carotid Artery Disease Be Prevented?

Taking action to control your risk factors can help prevent or delay carotid artery disease and stroke. Your risk for carotid artery disease increases with the number of risk factors you have.

One step you can take is to adopt a healthy lifestyle. Following a healthy diet is an important part of a healthy lifestyle.

A healthy diet includes a variety of fruits, vegetables, and whole grains. It also includes lean meats, poultry, fish, beans, and fat-free or low-fat milk or milk products. A healthy diet is low in saturated fat, trans fat, cholesterol, sodium (salt), and added sugar.

The National Heart, Lung, and Blood Institute's (NHLBI's) Therapeutic Lifestyle Changes (TLC) and Dietary Approaches to Stop Hypertension (DASH) are two programs that promote healthy eating.

If you're overweight or obese, work with your doctor to create a reasonable weight-loss plan. Controlling your weight helps you control carotid artery disease risk factors.

Try to do physical activity regularly. Physical activity can improve your fitness level and your health. Ask your doctor about what types of activity are safe for you.

If you smoke, quit. Smoking can damage and tighten blood vessels and raise your risk of carotid artery disease. Talk with your doctor about programs and products that can help you quit. Also, try to avoid secondhand smoke.

Know your family history of health problems related to carotid artery disease. If you or someone in your family has this disease, be sure to tell your doctor.

If lifestyle changes aren't enough, you also may need medicines to control your risk factors. Take all of your medicines as prescribed.

For more information about lifestyle changes and medicines, go to “How Is Carotid Artery Disease Treated?”

Living With Carotid Artery Disease

If you have carotid artery disease, you can take steps to manage the condition, reduce risk factors, and prevent complications. These steps include making lifestyle changes, following your treatment plan, and getting ongoing care.

Having carotid artery disease raises your risk of having a stroke. Know the warning signs of a stroke—such as weakness and trouble speaking—and what to do if they occur. Call 9–1–1 as soon as symptoms start (do not drive yourself to the hospital).

For more detailed information about the warning signs of a stroke, go to the section on warning signs below.

Lifestyle Changes

• Follow a healthy diet that's low in fats, sodium (salt), and cholesterol. The National Heart, Lung, and Blood Institute's “Your Guide to Lowering Your Cholesterol With TLC” and “Your Guide to Lowering Your Blood Pressure With DASH” are two programs that promote healthy eating.
• Be physically active. Check with your doctor first to find out how much and what kinds of activity are safe for you.
• If you're overweight or obese, lose weight.
• If you smoke, quit. Also, try to avoid secondhand smoke.

For more information about lifestyle changes, go to “How Is Carotid Artery Disease Treated?”

Treatment Plan

Following your treatment plan may help prevent your carotid artery disease from getting worse. It also can lower your risk for stroke and other health problems.

You may need to take medicines to control certain risk factors and to prevent blood clots that could cause a stroke. Taking prescribed medicines and following a healthy lifestyle can help control carotid artery disease. However, they don't cure the disease. You'll likely have to stick with your treatment plan for life.

Ongoing Care

If you have carotid artery disease, having ongoing medical care is important.

Most people who have the disease will need to have their blood pressure checked regularly and their blood sugar and blood cholesterol levels tested one or more times a year. If you have diabetes, you'll need routine blood sugar tests and other tests.

Testing shows whether these conditions are under control, or whether your doctor needs to adjust your treatment for better results.

If you've had a stroke or procedures to restore blood flow in your carotid arteries, you'll likely need a yearly carotid Doppler ultrasound test. This test shows how well blood flows through your carotid arteries.

Repeating this test over time will show whether the narrowing in your carotid arteries is getting worse. Results also can show how well procedures to treat your arteries have worked.

Follow up with your doctor regularly. The sooner your doctor spots problems, the sooner he or she can prescribe treatment.

Stroke Warning Signs

The signs and symptoms of stroke may include:

• Sudden weakness or numbness in the face or limbs, often on only one side of the body
• The inability to move one or more of your limbs
• Trouble speaking or understanding speech
• Sudden trouble seeing in one or both eyes
• Dizziness or loss of balance
• A sudden, severe headache with no known cause

Call 9–1–1 for help as soon as symptoms start. Do not drive yourself to the hospital. It's very important to get checked and treated as soon as possible.

If you're a candidate for clot-busting therapy, you have the best chance for full recovery if treatment to open a blocked artery is given within 4 hours of symptom onset. The sooner treatment occurs, the better your chances of recovery.

Make those close to you aware of stroke symptoms and the need for urgent action. Learning the signs and symptoms of a stroke will allow you to help yourself or someone close to you lower the risk of damage or death due to a stroke.

Clinical Trials

The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.

NHLBI-supported research has led to many advances in medical knowledge and care. Often, these advances depend on the willingness of volunteers to take part in clinical trials.

Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions. For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.

By taking part in a clinical trial, you can gain access to new treatments before they're widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don't directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.

If you volunteer for a clinical trial, the research will be explained to you in detail. You'll learn about treatments and tests you may receive, and the benefits and risks they may pose. You'll also be given a chance to ask questions about the research. This process is called informed consent.

If you agree to take part in the trial, you'll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.

For more information about clinical trials related to carotid artery disease, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:

• http://clinicalresearch.nih.gov
• www.clinicaltrials.gov
• www.nhlbi.nih.gov/studies/index.htm
• www.researchmatch.org

Links to Other Information About Carotid Artery Disease

NHLBI Resources

• "Aim for a Healthy Weight" Patient Booklet
• Aim for a Healthy Weight Web Site
• Atherosclerosis (Health Topics)
• Carotid Endarterectomy (Health Topics)
• Carotid Ultrasound (Health Topics)
• Keep the Beat™ Deliciously Healthy Eating
• Stents (Health Topics)
• "Your Guide to Lowering Your Blood Pressure With DASH"
• "Your Guide to Lowering Your Cholesterol With TLC"

Non-NHLBI Resources

• Carotid Artery Disease (MedlinePlus)
• Carotid Artery Surgery (MedlinePlus)
• Carotid Ultrasound (MedlinePlus)
• Carotid Endarterectomy: Interactive Tutorial (MedlinePlus)
• Stroke (National Institute of Neurological Disorders and Stroke (NINDS))
• Transient Ischemic Attack (NINDS)

Clinical Trials

• Clinical Trials (Health Topics)
• Current Research (ClinicalTrials.gov)
• NHLBI Clinical Trials
• NIH Clinical Research Trials and You (National Institutes of Health)
• ResearchMatch (funded by the National Institutes of Health)