Carotid Artery Disease
What is it?
- Carotid artery disease occurs when fatty deposits called plaques clog your carotid arteries. Your carotid arteries are a pair of blood vessels that deliver blood to your brain and head. The buildup of plaques in these arteries blocks the blood supply to your brain and increases your risk of stroke.
- Because carotid artery disease develops slowly and often goes unnoticed, the first outward clue that you have the condition may be a stroke or transient ischemic attack (TIA), also called a ministroke.
- Treatment of carotid artery disease usually involves a combination of lifestyle changes, medications and, in some cases, surgery or a stenting procedure.
In its early stages, carotid artery disease often doesn't produce any signs or symptoms. You and your doctor may not know you have carotid artery disease until it's serious enough to deprive your brain of blood.
If that happens, you may develop signs and symptoms of a stroke or TIA — an early warning sign of a future stroke. These signs and symptoms may include:
- Sudden numbness or weakness involving your face, arm or leg, typically on one side of your body
- Slurred or garbled speech or difficulty understanding others
- Sudden blindness in one eyeIf you experience any of these symptoms, you may be having a stroke. Seek immediate medical attention.
Even if the signs and symptoms last only a short while — usually less than an hour but, technically, anything less than 24 hours — and then you feel normal, tell your doctor right away. What you may have experienced is a transient ischemic attack (TIA), a temporary shortage of blood to your brain. A TIA is an important sign that you're at high risk of having a full-blown stroke, so don't ignore it.
Normal, healthy carotid arteries — like any other healthy artery — are smooth and flexible and provide a clear pathway for blood flow. If you place a finger under your jawbone, on either side of your Adam's apple, you're likely to feel your carotid artery pulse. Your carotid arteries carry oxygen- and nutrient-rich blood to your cerebral cortex and other vital brain structures, which are responsible for your day-to-day functioning.
Over time, however, the carotid arteries can become stiff and narrow due to a gradual accumulation of plaques, a process called atherosclerosis. Plaques consist of clumps of cholesterol, calcium, fibrous tissue and other cellular debris that gather at microscopic injury sites within the artery. When a lot of these plaques accumulate, narrowing the carotid artery and substantially restricting blood flow, doctors label this as carotid artery disease.
Factors that stress your arteries and increase the risk of injury, buildup of plaques and disease include the following:
- Aging. With age, your arteries become less elastic and more prone to injury.
- High blood pressure. High blood pressure is an important risk factor for carotid artery disease. Excess pressure on the walls of your arteries can weaken them and leave them more vulnerable to damage.
- Smoking. Nicotine can irritate the inner lining of your arteries. It also increases your heart rate and blood pressure.
- Abnormal blood-fat levels. High levels of low-density lipoprotein (LDL) cholesterol, the "bad" cholesterol, and high levels of triglycerides, a blood fat, encourage the accumulation of plaques.
- Diabetes. Diabetes affects not only your ability to handle glucose appropriately, but also your ability to process fats efficiently, placing you at greater risk of high blood pressure and atherosclerosis.
- Obesity. Carrying excess pounds increases your chances of high blood pressure, atherosclerosis and diabetes.
- Heredity. Having a family history of atherosclerosis or coronary artery disease increases your risk of developing these conditions, as well.
- Physical inactivity. Lack of exercise contributes to a number of conditions, including high blood pressure, diabetes and obesity.
Often, these risk factors occur together, creating even greater risk than if they occur alone.
The most serious complication of carotid artery disease is stroke. There are different ways carotid artery disease can increase your risk of stroke:
- Reduced blood flow. A carotid artery may become so narrowed by atherosclerosis that not enough blood is able to reach portions of your brain.
- Ruptured plaque. A piece of a plaque may break off and flow to smaller arteries in your brain (cerebral arteries). The fragment may get stuck in one of these smaller arteries, creating a blockage that cuts off blood supply to the area of the brain that the cerebral artery serves (stroke).
- Blood clot blockage. Some plaques are prone to cracking and forming irregular surfaces on the artery wall. When this happens, your body reacts as if to an injury and sends platelets — blood cells that help the clotting process — to the area. A large blood clot may develop in this manner and block or slow the flow of blood through a carotid or cerebral artery, causing a stroke.
A stroke can leave you with permanent brain damage and muscle weakness. In severe cases, it can be fatal.
In addition to taking a thorough medical history and recording risk factors and any signs or symptoms, your doctor may conduct or request several tests to evaluate the health of your carotid arteries:
- Physical examination. Your doctor may hear a "swooshing" sound (bruit) over the carotid artery in your neck, a sound that's characteristic of a narrowed artery. Or your doctor may observe cholesterol fragments (emboli) in the tiny blood vessels of your retina, at the back of your eye, during an eye examination. A test that compares the arterial blood pressure in each eye with the blood pressure in each arm also may be done.
- Ultrasound. A common, noninvasive test used to check for carotid artery disease is a Doppler ultrasound. This variation of the conventional ultrasound assesses blood flow and pressure — and possible narrowing of the blood vessel — by bouncing high-frequency sound waves (ultrasound) off red blood cells.
- Computerized tomography angiography (CTA). This imaging test uses a contrast dye to highlight your carotid arteries in the pictures taken. The dye is injected into a blood vessel. When it travels to your carotid arteries, a computerized tomography (CT) scan gathers X-ray images of your neck and brain from many angles.
- Magnetic resonance angiography (MRA). Like CTA, this imaging test uses a contrast dye to highlight the arteries in your neck and brain. A magnetic field and radio waves are used to create cross-sectional, 3-D images.
- Cerebral angiogram. A more traditional, and more invasive, imaging procedure called a cerebral angiogram may sometimes be done, but its use is less common, as it carries a slight risk of stroke. In this procedure, contrast dye is injected with a catheter that's been threaded directly into your carotid arteries. Detailed X-ray images are then taken.
Treatments and drugs
The goal in treating carotid artery disease is preventing stroke. The method of treatment depends on how narrow your arteries have become:
- In mild to moderate cases, lifestyle changes and medications may be sufficient to prevent stroke.
- If blockage is severe or if you've already had a TIA or stroke, surgery or a stenting procedure may be necessary.
Quitting smoking, losing weight, eating healthy foods and exercising regularly are important steps in reducing the stress on your arteries and slowing the progression of atherosclerosis. Lowering the sodium content of your food also may help.
It's also key to manage any chronic conditions you may have, as prescribed by your doctor. If you have high blood pressure, it's important that you stay at or under your blood pressure goal. Similarly, it's important to control your blood sugar levels if you have diabetes, or lower your cholesterol if you have high cholesterol levels.
Your doctor may ask you to take a daily aspirin or another blood-thinning medicine to avoid the formation of dangerous blood clots. He or she may also recommend medications to control your blood pressure, such as angiotensin-converting enzyme (ACE) inhibitors or calcium channel blockers, or a statin medication to lower your cholesterol.
If narrowing in a carotid artery is severe, and especially if you've already experienced a TIA or stroke, it's best to open up the artery and remove the blockage. There are two ways to do this:
- Carotid endarterectomy. This surgical procedure is the most common treatment for severe carotid artery disease. The procedure is done under either local or general anesthesia. After making an incision along the front of your neck, your surgeon opens the affected carotid artery and removes the plaques. The artery is repaired with either stitches or a graft. Studies have also shown that the surgery is low risk in most otherwise healthy people, has lasting benefit and helps prevent strokes.
- Carotid angioplasty and stenting. A carotid endarterectomy isn't recommended when the location of the narrowing or blockage is too difficult for the surgeon to access directly, or when you have other health conditions that make surgery too risky. In such cases, your doctor may recommend a procedure called carotid angioplasty and stenting. While you're under local anesthesia, a tiny balloon is threaded by catheter to the area where your carotid artery is clogged. The balloon is inflated to widen the artery, and a small wire-mesh coil called a stent is inserted to keep the artery from narrowing again. Because the procedure is relatively new, its durability and long-term ability to prevent stroke are still under investigation.
Making healthy choices in your daily life can help prevent or slow the progression of carotid artery disease, and help prevent the occurrence of a TIA or a stroke. Here are some suggestions:
- Don't smoke. Stopping smoking reduces stress on your arteries and cuts your risk of a TIA or a stroke. Within a few years of quitting, a former smoker's risk of stroke is similar to a nonsmoker's. It's never too late to quit. It's also never too early.
- Limit cholesterol and fat. Cutting back on cholesterol and fat, especially saturated fat, in your diet may reduce buildup of plaques in your arteries.
- Eat a variety of fruits and vegetables. These foods contain such nutrients as potassium, folate and antioxidants, which may protect against a TIA or a stroke.
- Limit sodium. Avoiding salt may not prevent hypertension, but excess sodium may increase blood pressure in people who are sensitive to sodium. For healthy adults, most experts recommend between 1,500 and 2,300 milligrams a day of sodium. If you have high blood pressure, keeping to the lower end of the range may help reduce your blood pressure.
- Exercise regularly. Exercise can lower your blood pressure, increase your level of high-density lipoprotein (HDL) cholesterol — the "good" cholesterol — and improve the overall health of your blood vessels and heart. It also helps you lose weight, control diabetes and reduce stress. If you have high blood pressure, engaging in 30 minutes of moderately vigorous activity (walking or swimming are two examples) on most days of the week is one of the few ways you can lower your pressure without drugs.
- Limit alcohol. Drink alcohol in moderation, if at all. The recommended limit is no more than one drink daily for women and two a day for men.
- Maintain a healthy weight. Being overweight contributes to other risk factors, such as high blood pressure, cardiovascular disease and diabetes. Losing weight with diet and exercise may lower your blood pressure and improve your cholesterol levels.
- Control chronic conditions. You can manage both diabetes and high blood pressure with diet, exercise, weight control and, when necessary, medication.