Last updated: 11/24/2009

Diagnosis

The presence and degree of stenosis in the carotid artery must be determined before a doctor decides that carotid endarterectomy is necessary. Carotid stenosis can sometimes be detected in a routine checkup, especially when...

a detailed history reveals to the doctor that the patient has experienced symptoms of TIA or stroke. The doctor will use a stethoscope to listen to blood flow in the carotid artery and may hear an abnormal rushing sound called a "bruit" (pronounced "brew-ee") that will indicate narrowing in the artery. The absence of sound, however, does not mean there is no risk. More extensive testing will most likely have to be done to determine the degree of stenosis and the potential of risk for the patient. These tests may include:

• Ultrasound imaging with Doppler—a painless, noninvasive imaging test that measures sound waves directed into the body and returned to the ultrasound machine as echoes. Usually these echoes are visualized as an image on a screen; Doppler captures the sound as the echoes bounce off of moving blood in the carotid artery, giving some indication of the amount of blockage as the ultrasound probe moves up and down the arteries on each side of the neck.
• Computed tomography (CT) or computer-assisted tomography (CAT scan)—a series of cross-sectional x rays of the head and brain that can rule out other causes for the symptoms but cannot detect carotid artery stenosis.
• Oculoplethysmography (OPG)—a procedure that measures the pulsing of arteries behind the eye, which can show carotid artery blockage.
• Arteriography and digital subtraction angiography (DSA)—special x-ray procedures using dye in the patient's vascular system. These tests are invasive and can actually cause a stroke, but they do indicate more exactly what degree of stenosis is present. The doctor will have to weigh the extent of risk and how much the patient will benefit from the tests.
• Magnetic resonance angiography (MRA)—an imaging test that does not use dyes or x rays and relies on special computer software and powerful magnetic fields to create a highly detailed image of the inside of the brain's arteries.

Preparation

If carotid ultrasonography or arteriography procedures were not performed earlier to diagnose carotid stenosis, these tests will be performed before surgery to evaluate the amount of plaque and the extent and location of narrowing in the patient's carotid arteries. Other blood vessels in the body are also evaluated. If other arteries show significant signs of artherosclerosis or damage, the patient's risk for surgery may be too great, and the procedure will not be performed. Aspirin therapy or other clot-prevention medication may be prescribed before surgery. Any underlying medical condition such as high blood pressure or heart disease will be treated prior to carotid endarterectomy to help achieve the best result from the surgery. Upon admission to the hospital, routine blood and urine tests will be performed.