Carotid artery stenosis

WHAT IS A CAROTID ARTERY STENOSIS?

Carotid artery stenosis is a narrowing in the blood vessel within the neck which leads directly to the brain. This narrowing is due to cholesterol build-up forming a plaque which can either break off and travel to the brain or completely block the artery. This blockage or traveling plaque can deprive the brain of blood which can lead to permanent damage called a stroke. Often patients have mini-strokes which are transient events due to this traveling plaque which passes to an area in the brain, but does not lead to permanent damage. These mini-stokes known as transient ischemic attacks (TIA) can be signs of an impending stroke.

SYMPTOMS

Symptoms of carotid artery stenosis can last for only several seconds or may last for an extended period of time. These symptoms require emergency evaluation and include: sudden difficulty or inability to speak or understand speech, difficultly or inability to move an arm or a leg, loss of vision in one or both eyes, loss of balance or coordination, numbness in the face, arm, or leg especially on one side of the body, and a sudden severe headache.

Hardening of the arteries (atherosclerosis) is the number one cause (90%) of carotid artery stenosis due to plaque build-up within this blood vessel. Other less likely risk factors include a degenerative process that affect the medium size blood vessels throughout the body (fibromuscular dysplasia), carotid artery kinking or coiling, radiation treatment, compression by tumors, trauma, blood vessel inflammation, and migraine headaches. Major risk factors for carotid artery stenosis include high blood pressure, Diabetes Type 1 and Diabetes Type 2, high cholesterol, obesity, sedentary life style, heredity, heart disease, and other blood vessel disease throughout the body.


DIAGNOSIS

Approximately 750,000 patients have a stroke per year in the United States. Often these strokes are due to carotid artery stenosis. To detect carotid artery stenosis a physician may hear an extra sound while listening to the side of the neck called a bruit. However, most patients with carotid artery stenosis are without this additional sound and carotid artery stenosis is detected due to a patient’s symptoms. Under either circumstance additional testing is required to confirm a diagnosis of carotid artery stenosis. The most common test is an ultrasound called a carotid artery duplex. This test can detect a range of blockages and not the exact percentage of the blockage. An angiogram which is a test involving the injection of a special dye which is detected by x-ray allowing a picture to outline the blood vessel and the blockage is able to detect the exact percent of blockage and the exact location of the blockage. Additional tests to evaluate carotid artery stenosis include CT (Computed tomography) angiogram and an MRA (Magnetic Resonance Angiography). Each is similar to an angiogram in that a picture is produced to demonstrate the area of blockage; however, angiograms are more exact. An angiogram; however, is an outpatient procedure which requires a small incision in the groin to allow a catheter to be positioned in the area to be examined.

Often after a stroke or mini-stroke a CT (Computed Tomography) or an MRI (Magnetic Resonance Imaging) of the brain may be obtained. These are done to estimate the amount and degree of damage which has been sustained by the stroke.

TREATMENT

Traditionally significant carotid artery stenosis has been treated with a surgical procedure called a carotid artery endarterectomy. The surgery is started with a 4 to 6 inch incision in the neck on the side of the blockage. The blood vessel is identified and encircled with tapes to control for bleeding. A blood thinner (Heparin) is administered to prevent clotting and the artery is clamped to allow a bloodless field. Often times a tube (shunt) will be placed in the artery before the blockage and into the area above the blockage to allow blood flow into the brain while operating on the blockage. The plaque is scraped clear of the normal blood vessel wall allowing for the blockage to be removed. The blood vessel is closed with a suture and the shunt and clamps are released. The incision is closed and the patient is taken to recovery. A patient will often remain in the hospital for one to two days after a carotid endarterectomy until discharge to home.

Recently, balloon angioplasty and stents have been used on carotid artery stenosis. This involves placing a small catheter in the groin to guide a balloon and stent into the area of blockage. The balloon and stent are expanded pushing the blockage aside to restore the normal caliber of the blood vessel.

COMPLICATIONS

Although the major purpose of surgery or balloon angioplasty with stenting is to prevent a stroke or mini-stroke, occasionally a stroke can result from plaque breaking loose during the procedure. Many techniques have been devised to prevent this complication and it occurs in only 2-6% of patients who have these procedures. Additional complications include bleeding, infection, stent misplacement, nerve injury, recurrent blockage, heart attack, and death.

PATIENT TIPS

Keywords: Stroke, High Blood Pressure, TIA (transient ischemic attack)

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