Carotid Artery Disease develops when the carotid arteries located in the front of the neck become blocked or narrow. These two arteries supply oxygen-rich blood to the part of the brain that controls movement, speech and sensation. If the cells in this area of the brain are depleted of oxygen, they die, which results in permanent damage or stroke. Carotid Artery Disease is similar to Coronary Artery Disease, which blocks blood flow in the arteries of the heart. Narrowing or blockage of the carotids, also known as stenosis, can cause symptoms, a stroke or even death.
Severe dizziness or near black-out
Severe unremitting headache
Sudden blurriness or even blindness in one eye
Sudden weakness or clumsiness of your hand
Sudden weakness or paralysis of an arm and/or leg
Unexplained slurring of your speech or garbled talk
If these things happen to you, or if they have happened recently, see your doctor and report them. A simple ultrasound scan can quickly and easily tell if you have severe Carotid Disease.
The Carotid Arteries are the main blood vessels to the brain. These arteries can develop a build-up of plaque caused by atherosclerosis, or "hardening of the arteries". When plaque in the carotid arteries (arrow) becomes very severe, a stroke can occur. This process is similar to the build up of plaque in the arteries to the heart that causes heart attacks. Since strokes occur in the brain, many doctors today refer to strokes as "brain attacks".
Signs & Symptoms of Carotid Artery Disease
Carotid Artery Disease often does not cause symptoms, but there are tests that can tell your doctor if you have it. If the arteries are very narrow, you may need an operation called an Endarterectomy to remove the plaque. For less severe narrowing, a medicine to prevent blood clots can reduce your risk of stroke. Another option for people who can't have surgery is Carotid Angioplasty. This involves placing balloons and/or stents into the artery to open it and hold it open. Most people with Carotid Artery Disease (CAD) have no symptoms.
Symptoms typically present themselves in the form of a transient ischemic attacks or mini strokes as they are called.
During a Transient Ischemic Attack (TIA), a person may experience temporary blindness, weakness in an arm or leg, dizziness, tingling sensations on the surface of the skin or numbness.
These mini attacks (TIA) rarely last more than 30 minutes, but people who have them are twice as likely as those who don't to have full-blown strokes.
Weakness, tingling, or numbness on one side of the body or in one arm or leg that comes on without apparent cause;
Temporary loss of control of movement in one arm or leg;
Partial loss of vision in one eye (often described as a window shade coming down) that typically lasts for 5 to 15 minutes; and
Inability to pronounce words or speak clearly.
Blurred or loss of vision in one or both eyes
Slurring of speech, difficulty talking or understanding what others are saying
Loss of coordination, dizziness or confusion
These symptoms usually go away completely within 24 hours. However, you should not ignore them. 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. Immediate treatment can save your life or increase your chance of full recovery.
If you experience the above symptoms for longer than a few hours, or they don't resolve within 24 hours, a stroke has probably occurred. You should contact your physician immediately.
Causes of Carotid Artery Disease
The risk factors for CAD are similar to those for Coronary Artery Disease. Some can be controlled and others can't.
Uncontrollable risk factors include:
Age & Sex: There is a greater risk for men than for women before the age of 75 years. After age 75, women have a higher risk of CAD.
Race: Race or ethnicity plays a role in CAD, too; black, Hispanic and Asian patients have a higher risk of CAD than whites.
Genetics: Genetics are involved; people with a family history of CAD or Coronary Artery Disease are at higher risk.
Controllable risk factors include:
Air Pollution: Air pollution is a risk factor that is controllable to a certain extent. Air pollution includes many environmental agents, such as carbon monoxide, nitrates, sulfur dioxide, ozone, lead, secondhand tobacco smoke etc.
Alcohol Consumption: Alcohol can contribute to high blood pressure, which can speed up atherosclerosis. Even a moderate amount of alcohol daily might increase the possibility of CAD and heart disease.
Diabetes: Diabetes, a chronic incurable disease, occurs when the pancreas does not produce enough insulin to regulate glucose levels. A person's glucose level is checked by monitoring the blood and urine. One of the long-term effects of uncontrolled diabetes is damage to blood vessels from atherosclerosis. A patient with diabetes is at a greater risk for stroke, heart attack and gangrene of the feet, as well as problems with the eyes, kidneys and nerves when blood vessels are damaged.
High Cholesterol: Cholesterol, like other fats found in the blood, protects nerves, makes cell tissues and produces certain hormones. Cholesterol is synthesized in the liver, but humans also acquire cholesterol through certain foods, such as egg yolks, meat, various oils, cheese and other dairy products.
Hypertension: It is estimated that I in every 4 adults has high blood pressure. A blood pressure level of 140/90 mmHg or higher is considered high. Hypertension can speed up atherosclerosis if it is not controlled. The constant force or hard pounding of blood against the artery wall damages the vessel and makes the heart work harder. Hypertension also can cause heart failure, kidney disease and blindness if not managed.
Obesity: Obesity is considered a risk factor if a person also has a high blood cholesterol level. Obesity can be associated with other risk factors, such as high blood pressure and diabetes. Most overweight people have low HDL cholesterol, which can increase the risk of CAD. Regular exercise can decrease heart rate, lower blood pressure, control weight and decrease the level of fats in the blood, all of which in turn decrease the risk of CAD.
Smoking: Smokers are at particular risk for atherosclerosis. The chemicals in cigarettes irritate the inner lining of the arteries, which causes inflammation of the artery walls. Smoking also increases the platelets' tendency to clot, which allows cholesterol to accumulate on the artery walls. Furthermore, smoking causes the adrenal glands to secrete a hormone that temporarily increases blood pressure and makes the heart work harder. As a result, the heart speeds up and blood pressure rises.
Diagnosis & Tests of Carotid Artery Disease
CAD is usually diagnosed during routine physical exams. Doctors can often detect the disease with a stethoscope by listening for murmurs caused by blood rushing through a narrowed part of the neck. However, doctors may not always be able to hear these sounds, which are called bruits (pronounced brew-ee), even when the CAD is severe. There are, therefore, several other tests for CAD.
Cerebral Arteriogram: An arteriogram, also called an angiogram, is an x-ray image of the blood vessels. A cerebral arteriogram is an arteriogram of the blood vessels of the brain. A Cerebral Arteriogram involves entering a catheter into the body to inject a dye (a contrast medium) into the carotid arteries, the vessels of the neck that lead to the brain. Then regular x-ray is used to image the dye that is flowing through the blood vessels; although cerebral angiography can be used to investigate many abnormalities.
A cerebral arteriogram may be performed to detect abnormalities of the blood vessels within or leading to the brain. Such abnormalities include Aneurysms, Stenosis, Arteriovenous Malformation (a condition in which there is an abnormal connection between the arteries and veins), Thrombosis (a blood clot within a blood vessel), or Occlusion (narrowing of a blood vessel).
A cerebral arteriogram may be recommended after a previous test, such as a CT scan, indicates the need for further information that may be obtained by this procedure. Cerebral Anteriogram is useful in detecting and diagnosing acute stroke and is especially beneficial since the images taken through cerebral angiography cannot be taken through other techniques.
The use of a catheter in cerebral angiography may cause you some discomfort or pain, although an anesthetic is usually given to help alleviate most discomfort. There is also a risk of stroke caused by the catheter.
CT Scans: A CT scan is usually one of the first tests done in a stroke evaluation, particularly during an acute stroke in the emergency room. This test can show areas of abnormalities in the brain, and can help to determine if these areas are caused by insufficient blood flow. Unlike other techniques, CT scans can show the inside of the head, including soft tissue, bones, brains and blood vessels. CT scans can often show the size and locations of brain abnormalities caused by tumors, blood vessel defects, blood clots, and other problems.
In brain CT imaging, a fan beam of x-rays is sent out through the skull, and a device on the other side of the scanner picks up the different strengths of the x-rays. After the x-ray tube and detector have made one 360° rotation, the image of one cross-section (a few millimeters in width) has been taken. During this rotation, hundreds of snapshots are taken, which are later used by a computer to make the final image.
MRA & MRI: Magnetic Resonance Angiography & Magnetic Resonance Imaging techniques use magnetic and radio waves to generate images of the arteries and the brain. The tests are able to detect even small strokes in the brain. An advantage of MRA is that it is noninvasive and thus has no related risk. This technique has eliminated the need to do a cerebral angiogram in most cases.
Medical images taken of the human body are usually displayed in three orientations:
1. Coronal Orientation: in a slice dividing the head into front and back halves.
2. Sagittal Orientation: in a slice dividing the head into left and right halves.
3. Axial Orientation: in a slice dividing the head into upper and lower halves.
The MRI does not involve X-rays and there are no side effects. However, if you have any metallic objects in your body, the magnetic field can cause dangerous interactions. It is essential that you tell your doctor or the technologist about any previous surgery, implanted devices such as pacemakers, bullets or shrapnel wounds.
Ultrasound Tests: A non-invasive method using continuous wave Doppler shift ultrasound and spectral analysis was used as a screening test for severe carotid artery disease in patients undergoing cardiopulmonary bypass operations. Patients with severe carotid artery disease proceeded to carotid arteriography and endarterectomy before the planned heart operation.
Prevention of Carotid Artery Disease
Most people with carotid artery disease don't need surgery. A little plaque in the carotid arteries is normal for most older Americans - it's part of the aging process. We get more concerned when plaques grow to the point where they cause a 60-70% blockage or more, or if they cause symptoms like TIA's. Obviously, if you have a little bit of plaque the goal is to prevent it from becoming worse! This is where medical treatments and your own personal efforts can have a tremendous effect. Here are some of the things that can be done to reduce your risks of getting worse:
If you smoke, stop smoking!
Achieve good blood pressure control. If you have hypertension (high blood pressure), follow your doctor's orders for treatment
Get regular exercise. It's good for your entire cardiovascular system and your metabolism
Control your blood cholesterol. If your doctor discovers that your cholesterol is high, then lowering it will be beneficial. This can often be done simply by changing what you eat, but there are also excellent medications that can really help. Studies have shown that lowering cholesterol levels can significantly reduce the risks of heart attacks and strokes
Treatment of Carotid Artery Disease
If you have been diagnosed with Carotid Artery Disease, your physician may refer you to an interventional radiologist or vascular specialist for treatment. Treatment options for Carotid Artery Disease that are performed by these specialists include carotid Endarterectomy and angioplasty and Stenting.
An interventional radiologist, a physician trained to use x rays and other imaging techniques to see inside the body, may perform some of these procedures. Interventional radiologists use long, flexible, thin tubes called catheters and other micro tools to treat conditions without surgery.
Treatment for carotid artery disease depends on your symptoms, the status of the vessels supplying blood to the brain, and the degree of narrowing in the carotid artery.
Carotid Angioplasty and Stenting: A newly developed minimally invasive procedure to treat carotid artery disease is angioplasty and stenting. Angioplasty and stenting is usually performed using a local anesthetic. To perform this procedure, your vascular surgeon may insert a long, thin tube called a catheter through a small puncture site over a groin artery and guide it through your blood vessels to your carotid artery. The catheter carries a tiny balloon that inflates and deflates, flattening the plaque against the walls of the artery. Next, the physician places a tiny metal-mesh tube called a stent in the artery to hold it open.
For patients who meet certain eligibility criteria, carotid stenting offers a less invasive approach than carotid endarterectomy, the traditional surgical treatment for carotid artery blockages. During carotid endarterectomy, an incision is made in the neck at the site of the carotid artery blockage. The artery is isolated and the plaque and diseased portions of the artery are surgically removed. Then, the artery is sewn back together to improve blood flow to the brain. In contrast, carotid stenting can be performed while the patient is awake, reducing recovery time and the risk of complications and re-narrowing.
Carotid Endarterectomy: Carotid Endarterectomy is the surgical procedure to remove fatty plaque from neck arteries. Fatty plaque is deposited on the interior walls of the neck (carotid) atteries as a in a condition known as Carotid Artery Disease. Carotid Artery Disease affects the vessels leading to the head and brain. Like the heart, the brain's cells need a constant supply of oxygen-rich blood. This blood supply is delivered to the brain by the 2 large carotid arteries in the front of the neck and by 2 smaller vertebral arteries at the back of the neck. The right and left vertebral arteries come together at the base of the brain to form what is called the basilar artery. A stroke most often occurs when the carotid arteries become blocked and the brain does not get enough oxygen.