Interventional Radiology

interventional radiology

CAD (Coronary Artery Disease)

Illustration of carotid artery stenosis

What are the carotid arteries?

Carotid arteriesYour arteries carry oxygen-rich blood away from the heart to the head and body. There are two carotid arteries (one on each side of the neck) that supply blood to the brain. You can feel your carotid arteries by feeling the pulse on your lower neck, on either side of your windpipe. The carotid arteries supply the large, front part of the brain, where thinking, speech, personality and sensory and motor functions reside. There are two smaller arteries, the vertebral arteries, which run through the spine and supply the back part of the brain (the brainstem and cerebellum).


What is carotid artery disease?
Like the blood vessels of the heart (coronary arteries), the carotid arteries also develop atherosclerosis, the build-up of fat and cholesterol deposits, called plaque, on the inside of the arteries. Over time, the build-up narrows the artery, decreases blood flow to the brain and can lead to a stroke. A stroke can occur if:
• the artery becomes extremely narrowed
• a piece of plaque breaks off and travels to the smaller arteries of the brain
• a clot forms and blocks a narrowed artery

A stroke is similar to a heart attack. A stroke occurs when brain cells (neurons) are deprived of the oxygen and sugar (glucose) carried to them by blood. Oxygen and glucose are essential for neurons to function and survive. If the lack of blood flow lasts for more than 3 to 6 hours, the damage is usually permanent.

The Two types of stroke

• Blood clots that block the artery are ischemic (is-KEM-ik) strokes and the most common type, causing between 70-80 percent of all strokes. Ischemic strokes are related to carotid artery disease. These strokes consist of a shower of clots to the brain.
• When a blood vessel ruptures, it causes a bleeding or hemorrhagic (hem-o-RAJ-ik) stroke. Such strokes are usually the result of a ruptured blood vessel or an aneurysm—a weakened area of a blood vessel that bulges or balloons out. Sometimes, abnormal tangles of blood vessels in the brain, called arteriovenous malformations (AVM) can rupture and cause a hemorrhagic stroke. Approximately 20 percent of strokes are hemorrhagic. This is the most common type of stroke in young people. Other minimally invasive procedures are available to treat this condition.

The risk factors for carotid artery disease

The risk factors for carotid artery disease are similar to those for coronary artery disease:

• Family history of atherosclerosis (either coronary artery disease or carotid artery disease)
• Age (greater in men less than age 75 than for women the same age, but higher in women after age 75)
• Smoking
• Hypertension
• Diabetes
• High low density lipoprotein (LDL, bad cholesterol) - although this link is not as strong as it is for coronary artery disease. If you have coronary artery disease, you are more likely to get carotid artery disease.

The symptoms of carotid artery disease

There may not be any symptoms of carotid artery disease. However, there are warning signs of a stroke. A transient ischemic attack (also called TIA or "mini-stroke") is one of the most important warning signs of a stroke. A TIA is a temporary episode of:

• blurred or loss of vision in one or both eyes
• weakness and/or numbness of your arm, leg or face on one side of your body
• slurring of speech, difficulty talking or understanding what others are saying
• loss of coordination, dizziness or confusion
• trouble swallowing

A TIA may last a few minutes or a few hours. A TIA is a medical emergency since it is impossible to predict if it will progress into a major stroke. If you or someone you knows experiences these symptoms, get emergency help (Call 911). Immediate treatment can save your life or increase your chance of full recovery.

How is carotid artery disease diagnosed?

Carotid artery disease may not have symptoms. It is important for those at risk to have regular physical exams by their doctor. A doctor will listen to the arteries in your neck with a stethoscope. An abnormal rushing sound, called a “bruit”, may indicate you have disease. Bruits are not always present when blockages are present and may be heard at times even with minor blockages. It is important to let your doctor know if you have had any symptoms, such as those listed above.

Diagnostic tests


Carotid Duplex Ultrasound – A non-invasive imaging procedure (also called echo) that uses high-frequency sound waves to view the blood vessels in the neck and to determine the presence of narrowing in the carotid arteries. This study is recommended in anyone with heart disease and anyone over the age of 60.

Carotid Duplex Ultrasound

Carotid Duplex Ultrasound

Computerized Tomography (CT Scan) and Computerized Tomography Angiogram (CT angio) - a CT angio of the neck vessels is a non invasive test which will reveal if there are narrowings in the carotid arteries reducing the blood flow to the brain. Usually, this procedure is performed if there is a possibility a stroke has already occurred of if there are symptoms related to TIAs. This test will also reveal areas of damage on the brain.
 

Computerized TomographyComputed Tomography image

Magnetic Resonance Imaging or MR Angiography (MRA) – An MRA of the neck blood vessels in non-invasive and may be performed to identify the narrowing of the carotid arteries. An MRI of the brain will also identify subtle areas of damage on the brain, resulting from showering of small blood clots from the carotid narrowing.
 

Carotid MRACarotid MRA

Carotids MRA showing narrowing in the left carotid artery

MRI perfusion MTT mapMRI perfusion MTT map

MRI perfusion MTT (maximum transit time) map.

The red areas in the right hemisphere of the brain in the image on the left shows the area of reduced blood flow. Note the improvement of the perfusion following carotid angioplasty and stenting on the image on the right. There is an area of permanent damage (stroke) within the involved brain hemisphere.


Carotid Angiography (carotid angiogram, carotid arteriogram, carotid angio) - If carotid artery disease is suspected, prior to treatment, your doctor may schedule an arteriogram. This is an invasive imaging procedure that involves inserting a catheter into a blood vessel in the groin vessels, and guiding it to the carotid arteries with the aid of a special x-ray machine called fluoroscope. Contrast dye is injected through the catheter so that x-ray pictures of your carotid arteries are taken. Carotid angiograms are usually performed when there is a question not answered by the non-invasive tests or in preparation for the endovascular treatment of the carotid narrowing by placing a stent.

Carotid arteriogram before carotid stentingCarotid arteriogram after carotid stenting

Example of carotid arteriogram before and after carotid stenting. Note the narrowing in the left common carotid artery and in the left internal carotid artery.

How is carotid artery disease treated?

Carotid artery disease is treated by:

• Lifestyle modification
• Medications
• Procedures

Lifestyle modification

To prevent further progression of disease, lifestyle modification is recommended to limit all risk factors for coronary and carotid artery disease. These include:

• Quit smoking and using tobacco products
• Control high blood pressure and diabetes
• Have regular check-ups with your doctor
• Have your doctor check your lipid profile and get treatment, if necessary to reach a lipid goal of LDL less than 100 and HDL greater than 45
• Eat foods low in saturated fats and cholesterol
• Achieve and maintain a desirable weight for your age and height
• Exercise regularly
• Control other stroke risk factors: limit the amount of alcohol you drink and if you have atrial fibrillation, you should be on blood-thinning medications

Medications

Blood-thinner (anticoagulant) medications - all patients with carotid disease should be on aspirin and Plavix to decrease the risk of stroke due to blood clots. In some cases, Coumadin (warfarin) may be prescribed. If so, blood work will need to be checked regularly to ensure you are on the proper dose.

Procedures

If the carotid artery has severe narrowing or blockage, a procedure must be done to open the artery and allow blood flow to the brain, to prevent future stroke:

Stent in the arteryCarotid Angioplasty and Stenting - This interventional procedure is still undergoing extensive investigation. Performed in a catheterization suite by interventional radiology, a small puncture is made in the groin under local anesthesia. A specially designed catheter, with an umbrella tip (a filter) is placed over a guide wire and directed to the area of narrowing in the carotid artery. Once in place, a small balloon tip is inflated for a few seconds to dilate the artery (balloon angioplasty). Then, the stent (a small metal mesh tube that acts as a scaffold to provide support inside the artery) is placed in the artery and opens to fit the size of the artery. Filters (called cerebral protection devices) are used to capture any particles (blood clots) that are released and prevent them from going to the brain and causing a stroke. The stent stays in place permanently. Over a period of several weeks, the artery heals around the stent. A lot of research is underway to study the effectiveness and safety of carotid stenting. Several clinical trials have already shown that carotid stenting is at least as safe and effective as open surgery, and in the fall of 2004 the first device for carotid stenting was approved by the U.S. FDA. For more information, click here.

Cerebral Protection Device recently approved by the FDA (Accunet)

Cerebral Protection Device recently approved by the FDA (Accunet)

Carotid Stent recently approved by the FDA (Acculink)Carotid Stent recently approved by the FDA (Acculink)

2 patients with carotid artery disease and with symptoms

Two patients with carotid artery disease and with symptoms (TIAs). The two pictures on the left depict a severe narrowing of the right carotid artery treated by stenting. On the right the carotid left carotid angiogram, shows before (3rd picture) and after carotid stenting (4th picture). Both cases were performed with the cerebral protection devices.

Carotid endarterectomy - This is the standard surgical treatment for carotid artery disease. While the patient is under general anesthesia, an incision is made in the neck, at the location of the blockage. The surgeon opens the carotid artery and removes the plaque and diseased portions of the artery. Then, the artery is sewn back together to allow blood flow to the brain.
 

When should carotid artery disease be treated?
Carotid artery disease is "symptomatic" or "asymptomatic." If an episode of amaurosis fugax (temporary loss of vision in just one eye) occurs, a TIA or a stroke, the disease is symptomatic. If carotid artery disease does not cause symptoms before it is detected, it is considered asymptomatic. Blood flowing through a narrowing in the artery may cause a noise that can be heard when a stethoscope is placed on the neck. This noise is called a bruit and may prompt your doctor to order an imaging test of the carotid arteries.

Asymptomatic carotid disease

A recent study involving more than 1600 patients suggests that if the carotid artery stenosis has never caused any symptoms, the artery should be repaired when the diameter of the artery narrows by 60 percent or more.

Before undergoing a surgical repair of a narrowed carotid artery, patients may wish to consider the following points:

• The physician performing the open operation or stenting must be experienced.
• The patient's general health should be good, with no significant illness that might otherwise increase the risks of the surgery or procedure. Each individual patient needs to be evaluated carefully before a decision is made to operate.

Symptomatic carotid disease

If the artery has caused symptoms and is narrowed by more than 70 percent, then surgery is strongly recommended to prevent further symptoms or stroke. If no surgery is performed, despite the symptoms and narrowing of the artery, the chance of a stroke is approximately 26 percent over two years. This risk is reduced to 9 percent if the artery is repaired. If the artery is narrowed by more than 50 percent but less than 70 percent, there still may be a benefit to repairing the artery to prevent future problems.

Artery narrowed less than 50%

There is no proven benefit to operate on an artery that is narrowed less than 50 percent. In that case, usually medical treatment is just as effective as surgical repair or stenting. Medical treatment may consist of taking one adult aspirin and Plavix a day and controlling the risk factors. However, each patient must be carefully evaluated and an individual treatment plan decided on with input from a team of physicians experienced in the treatment of carotid artery disease, the patient and the patient's family.

Interventional Radiology at MUSC
The Division of Interventional Radiology at the MUSC Heart and Vascular Center has more than 10 years experience in the treatment of the narrowings of the carotid arteries and has been working in the development of several of the devices for the endovascular treatment of carotid occlusive disease, as well as in the perfecting of the cerebral protection devices, which remarkably reduce the potential complications of the procedure.

Contact Us

To talk to one of our Interventional Radiologists to know more about Carotid Angioplasty and Stenting or to make an appointment, please call:

RN Patient Care Coordinator
Marlene O'Leary, RN
Phone: 843-792-8406
FAX: 843-792-9068
e-mail: olearym@musc.edu

Or

Secretary for Interventional Radiology
Sandra Stringer
Phone: 843-792-5387
FAX: 843-792-9276
e-mail: stringes@musc.edu


Learn more about carotid disease on other sites

http://www.sirweb.org/patPub/stroke.shtml

http://www.nlm.nih.gov/medlineplus/

http://www.americanheart.org/

 
 
 

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