Carotid disease

Definition

Carotid disease occurs when the major arteries of the neck that supply blood to the brain become narrowed or blocked.

Description

The carotid arteries are two large blood vessels that deliver blood from the heart through the neck to the brain. They are found on each side of the neck, where the pulse can be felt below the jaw bone. Arteries are normally smooth and unobstructed on the inside, but with aging, a sticky substance called plaque can build up on their inner walls causing them to narrow. Narrowing or blockage of the carotid arteries

decreases the blood flow to the brain, resulting in a condition known as carotid artery disease. The disease is considered serious, because it may lead to interruptions in blood flow to the brain (stroke ) that can cause permanent injury and disability.

Demographics

Each year in the United States, there are more than 700,000 new cases of stroke. Stroke is the third leading cause of death in the country, after heart disease and cancer . Stroke also causes more serious long-term disabilities than any other disease. Nearly three-quarters of all strokes occur in people over the age of 65. And the risk of having a stroke more than doubles each decade after the age of 55. The risk of developing carotid artery disease also increases with age. According to the Society for Vascular Surgery, only 1% of adults in the 50–59 age group have significantly narrowed carotid arteries, compared to 10% of adults in the 80–89 group.

Causes and symptoms

Carotid disease is due to the accumulation of plaque on the inner walls of carotid arteries. Plaque mostly consists of cholesterol, calcium , and fibrous tissue. As more plaque builds up, the arteries narrow and stiffen (atherosclerosis ).

There are no symptoms specific to carotid artery disease, but “mini-strokes,” or transient ischemic attacks (TIAs), may be experienced with the following symptoms:

• weakness or paralysis of arm, leg, or face on one side of the body
• numbness or tingling in an arm, leg, or face on one side of the body
• difficulty swallowing
• loss of vision or blurry eyesight in one eye
• dizziness, confusion, fainting, or coma
• sudden, severe headache

Diagnosis

Carotid disease can be screened for during a physical examination. The physician may ask if a person has had symptoms such as muscle weakness or numbness, or trouble talking or seeing. Using a stethoscope, the physician can listen for abnormal sounds produced by blood rushing through narrowed carotid arteries (bruit). However, bruit sounds may not always be present, even when carotid artery disease is severe. Other tests may be performed, including:

• Arteriography, a procedure that uses injection of a dye to outline the arteries on an x ray.
• Digital subtraction angiography (DSA), a procedure used to clearly visualize blood vessels in a bony or dense soft tissue environment.
• Doppler ultrasonography, an ultrasound-based diagnostic imaging technique used to visualize internal organs, their size, structures and possible lesions.
• Magnetic resonance angiography (MRA), a technique that uses a magnetic field and pulses of radiowave energy to provide pictures of blood vessels inside the body.
• Oculoplethysmography, a method for measuring the ophthalmic artery pressure, which reflects pressure and flow in the internal carotid artery.

Treatment

Medical treatments for carotid artery disease includes careful management of blood pressure , cholesterol, and diabetes (if present) to prevent worsening of atherosclerosis. Treatment is aimed at lowering the risk of stroke and may include lifestyle changes, medications, angioplasty interventions, or surgery.

In some cases, a procedure called carotid angioplasty is used to widen arteries. It uses a balloon catheter to flatten plaque blockages against the artery wall, opening the passageway. A metal, tube-like device called a stent may then be inserted in the artery to keep it open.

A carotid endarterectomy is a surgical procedure used to remove plaque from carotid arteries. It is performed with the patient under general anesthesia . An incision is made in the neck at the location of the blockage, and a tube is inserted above and below the blockage to redirect blood flow. The surgeon can then open up the artery to remove the plaque. Once the artery is stitched closed, the tube is removed. The procedure can also be carried out using a technique that does not require redirecting blood flow. The surgeon stops the blood flow just long enough to scrape the deposit away from the artery.

Nutrition/Dietetic concerns

High levels of low-density lipoprotein (LDL) cholesterol, the “bad” cholesterol, and high levels of triglycerides, a blood fat, promote the development of plaques. A healthy diet is accordingly important to lower stress on arteries and slow the progression of atherosclerosis. Eating a variety of fruits and vegetables is considered an important dietary requirement, as these foods contain potassium, folate and antioxidants , which may protect against a TIA. Alcohol intake should also be moderate, with most health practitioners recommending no more than one drink daily for women and two for men.

QUESTIONS TO ASK YOUR DOCTOR

• Why do I need to take a blood thinner?
• What if I am taking other medicines?
• What are the side effects?
• How long will I need to take them?
• Are there any risks associated with endarterectomy?

Therapy

Antiplatelet and blood-thinning therapy using anticoagulant medications may be prescribed, as they have been shown to lessen the risk of stroke. In most cases, patients are required to take these medications for the rest of their lives. Some brand names include: Coumadin (warfarin), Dicumarol (dicumarol), Miradon (anisinidione). Another medication that may be prescribed to dissolve blood clots is tissue plasminogen activator (t-PA). It is used in the treatment of stroke caused by blood clots (ischemic stroke).

Prognosis

Carotid artery disease increases the risk of stroke. Surgical outcomes are good, with postoperative stroke occurring in 1–5% of patients with carotid artery disease. Following successful carotid endarterectomy, the 2-year stroke risk is estimated at 1.6%, compared with 12.2% for patients managed with medications. Overall, the risk of major stroke following treatment is reduced from approximately 1 in 5 persons to 1 in 25.

Prevention

Lifestyle changes may prevent or limit the progression of carotid artery disease. Smoking should be avoided. Other changes that decrease the risk of carotid artery disease include losing weight, exercising regularly, and controlling high blood pressure, cholesterol, and diabetes if present. Another preventive measure is screening for heart rhythm problems, especially atrial fibrillation, which increases the risk of blood clots that can lead to stroke.

KEY TERMS

Anticoagulants —Also called blood thinners, these medications decrease the blood's ability to clot. Decreased clotting keeps fewer harmful blood clots from forming and from blocking blood vessels.

Antiplatelet therapy —Drug treatment to inhibit platelet activation and aggregation.

Atrial fibrillation —A heart rhythm disorder (arrhythmia).

Blood clot —A gelled mass of blood tissue.

Carotid artery —A blood vessel that supplies the brain with oxygenated blood.

Plaque —A semi—hardened accumulation of substances from fluids that bathe an area. Plaques on the inner walls of blood vessels can lead to blood clot formation, heart attacks, and stroke.

Platelet —A small blood cell needed for normal blood clotting.

Stenosis —Abnormal narrowing of a passage or opening, such as a blood vessel or heart valve.

Tissue plasminogen activator (t—PA) —Clot—dissolving medicine approved by the U.S. Food and Drug Administration (FDA).

Caregiver concerns

Little information is available on carotid artery disease in independently living elderly individuals. In a recent study involving 239 apparently healthy subjects aged 65–94 years, the prevalence of artery disease was found to be high with 31.8% of participants showing plaque growth in carotid arteries and 7.7%with stenosis or occlusion. These results suggest that screening for carotid disease should be encouraged in this patient group.

Resources

BOOKS

Chaturvedi, Seemant, and Peter M. Rothwell, editors. Carotid Artery Stenosis: Current and Emerging Treatments. London, UK: Informa Healthcare, 2005.

DeFelice, Eugene A. Prevention of Cardiovascular Disease: Atherosclerosis, Carotid Artery Disease, Cerebral Artery Disease/Stroke, Coronary Artery Disease, Peripheral Artery Disease and Hypertension. Lincoln, NE: iUniverse, 2005.

Gillard, J., et al., editors. Carotid Disease: The Role of Imaging in Diagnosis and Management. Cambridge, UK: Cambridge University Press, 2006.

PERIODICALS

Amato, B., et al. “Carotid endarterectomy under local anesthesia in elderly: Is it worthwhile?” Acta Bio-medica 76, suppl. 1 (2005): 64–68.

American College of Physicians. “Screening for Blockages in the Blood Vessels to the Brain: Recommendations from the U.S. Preventive Services Task Force.” Summaries for Patients 147, no. 12 (December 2007): 1–36.

Debing, E., and P. van den Brande. “Carotid endarterectomy in the elderly: Are the patient characteristics, the early outcome, and the predictors the same as those in younger patients?” Surgical Neurology 67, no. 5 (May 2007): 467–471.

Ellingsen, I., et al. “Consumption of fruit and berries is inversely associated with carotid atherosclerosis in elderly men.” British Journal of Nutrition 99, no. 3 (March 2007): 674–681.

Hassinen, M., et al. “Association of waist and hip circumference with 12–year progression of carotid intima-media thickness in elderly women.” International Journal of Obesity 31, no. 9 (September 2007): 1406–1411.

Kadkhodayan, Y., et al. “Carotid angioplasty and stenting in the elderly.” Neuroradiology 49, no. 11 (November 2007): 933–938.

Kawamoto, R., et al. “Non-HDL cholesterol as a predictor of carotid atherosclerosis in the elderly.” Journal of Atherosclerosis and Thrombosis 12, no. 3 (2005): 143–148.

Lipsitz, L. A., et al. “Antihypertensive therapy increases cerebral blood flow and carotid distensibility in hypertensive elderly subjects.” Hypertension 45, no. 2 (February 2005): 216–221.

Sobieszczyk, P., and J. Beckman. “Carotid Artery Disease.” Circulation 114 (2006): e244–e247.

OTHER

Blood-Thinning Medicines. Texas heart Institute, Heart Information Center (February 20, 2008) http://www.texasheartinstitute.org/HIC/Topics/Meds/blodmeds.cfm.

Carotid Artery Disease. Texas heart Institute, Information Page (February 20, 2008) http://www.texasheartinstitute.org/HIC/Topics/Cond/CarotidArteryDisease.cfm.

Carotid Artery Disease. Cleveland Clinic, Information Page (February 20, 2008) http://www.clevelandclinic.org/heartcenter/pub/guide/disease/vascular/carotidartery.htm.

Carotid Artery Disease. Peripheral Vascular Surgery Society, Patient Information Page (February 20, 2008) http://www.pvss.org/PatientInfo/carotid.htm.

Carotid Artery Disease. Mayo Clinic, Information Page (February 20, 2008) http://www.mayoclinic.com/health/carotid-artery-disease/DS01030.

Carotid Artery Disease. Texas heart Institute, Information Page (February 20, 2008) http://www.texasheartinstitute.org/HIC/Topics/Cond/CarotidArteryDisease.cfm.

ORGANIZATIONS

American Stroke Association: A Division of American Heart Association, 7272 Greenville Ave., Dallas, TX, 75231-4596, (414)272-6071, (888)4STROKE, (214)706-5231, http://www.strokeassociation.org.

National Institute of Neurological Disorders and Stroke (NINDS), P.O. Box 5801, Bethesda, MD, 20824, (301) 496-5751, (800) 352-9424, http://www.ninds.nih.gov.

National Stroke Association, 9707 East Easter Lane, Englewood, CO, 80112-3747, (303) 649-9299, (800) STROKES, (303) 649-1328, info@stroke.org, http//www.stroke.org.

Monique Laberge Ph.D.