Carotid Endarterectomy and Stenosis
September, 2005
Carotid endarterectomy is a common vascular surgical procedure
which may help prevent your risk of having a stroke. Scientific evidence
from recent studies supports carotid endarterectomy as an effective
method of stroke prevention for people with carotid artery blockage of
70 percent or greater. It also may be beneficial for people with
moderate blockage of 50 to 69 percent and recent symptoms of stroke.
The carotid arteries are the main blood vessels to your brain.
Carotid arteries are located on each side of your neck and extend from
your aorta in your chest to the base of your skull. These arteries
supply oxygen-rich blood to your brain. Plaque forms when the internal
carotid arteries become blocked by fat and cholesterol build-up. This
process is called atherosclerosis. Blockage of the internal carotid
arteries can reduce blood supply to the brain, and may lead to a stroke.
The plaque may cause the blood to flow abnormally, which may lead
to blood clots. A clot may remain at the site of narrowing and prevent
blood flow to all of the smaller arteries it supplies. Alternatively, a
clot can travel and wedge into smaller vessels. This is called an
embolism. If a clot or plaque blocks the blood flow to your brain, it
can lead to an ischemic stroke, which may cause brain damage or death.
If a clot or plaque blocks a tiny artery in the brain, it may cause a
transient ischemic attack (TIA), also known as a mini-stroke.
Severe blockage is called carotid stenosis. Carotid stenosis may
cause you to experience a TIA. Common temporary symptoms include
difficulty speaking or understanding others, loss or blurring of vision
in one eye, and loss of strength or numbness in an arm or leg. Usually
these symptoms resolve in less than 10 to 20 minutes, and almost always
within one hour. Even if all the symptoms resolve, it is very important
that anyone experiencing these symptoms call 911 and immediately be
evaluated by a qualified doctor.
Carotid stenosis is frequently asymptomatic. Your doctor may
detect it through an abnormal sound called a bruit (BROO'e) when
listening to your carotid arteries with a stethoscope.
Prior to determining if you are a candidate for a carotid
endarterectomy, your doctor will give you a thorough examination,
including your medical history. Individuals with the following medical
conditions are at higher risk of having complications from this surgery:
- Past strokes, especially large strokes without recovery
- A
heart attack within the last six months
- Congestive heart
failure
- Uncontrolled high blood pressure
- Unstable
angina (chest pains)
- The presence of a serious disease, such as
severe heart or lung disease
- Widespread cancer with less than a
2-year life expectancy
- Plaque that cannot be reached through
surgery
- Severe blockage in other blood vessels that supply
blood to your brain, such as the carotid artery on the other side
- New
blockage in a previous carotid endarterectomy on the same side
- Alzheimer’s
or other progressive brain disorders
- Diabetes
Your
doctor may order tests to help diagnose the extent of blockage. These
tests include:
Cerebral angiography (also called vertebral angiogram,
carotid angiogram)
Your arteries are not normally seen in an x-ray, so contrast dye
is utilized. You are given a local anesthetic, the artery is punctured,
usually in your leg, and a needle is inserted into your artery. A
catheter (a long, narrow, flexible tube) is inserted through the needle
and into your artery. It is then threaded through the main vessels of
the abdomen and chest until it is properly placed in the arteries of the
neck. This procedure is monitored by a fluoroscope (a special x-ray
that projects the images on a TV monitor). The contrast dye is then
injected into the neck area through the catheter, and x-ray pictures are
taken. Your pulse, blood pressure, and breathing are monitored during
this procedure. Risks of this procedure include:
- An allergic reaction to the contrast dye
- Although rare, the catheter may damage the artery or knock
loose a piece of the artery wall, which can block blood flow and cause a
stroke
- A clot or bleeding at the puncture site may result in a
partial blockage of blood flow to the leg
Carotid duplex (also called carotid ultrasound)
In this procedure, ultrasound is used to help detect plaque,
blood clots, or other problems with blood flow in the carotid arteries.
Ultrasonography is very reliable in identifying stenosis, but does not
accurately assess the degree of stenosis. Because treatment is based on
the degree of stenosis, treatment decisions cannot be made from
ultrasonography alone.
A water-soluble gel is placed on your skin where the transducer
(a handheld device that directs the high-frequency sound waves to the
arteries being tested) is to be placed. The gel helps transmit the sound
to your skin surface. The ultrasound is turned on and images of the
carotid arteries and pulse wave forms are obtained. There are no known
risks and this test is noninvasive and painless.
Additional tests may include:
Magnetic Resonance Angiography (MRA)
This is a noninvasive study which is conducted in a Magnetic
Resonance Imager (MRI). The magnetic images are assembled by a computer
to provide an image of the arteries in your head and neck. No contrast
material is needed, but some patients may experience claustrophobia in
the imager.
Magnetic Resonance Imaging (MRI)
This is a diagnostic test that produces three-dimensional images
of your head using powerful magnets and computer technology.
Carotid Endarterectomy Surgery
You will be given either a general or local anesthetic before
surgery. In this procedure, the neurosurgeon makes an incision in your
carotid artery and removes the plaque using a dissecting tool. Removing
the plaque is accomplished by widening the passageway, which helps to
restore normal blood flow. Your artery will be repaired with sutures or a
graft. The entire procedure usually takes about two hours. You may
experience pain near the incision in your neck and some difficulty
swallowing during the first few days after surgery. Most patients are
able to go home after one or two days, and return to work, usually
within a month. You should avoid driving and limit physical activities
for a few weeks after your surgery.
There are potential complications with carotid endarterectomy
surgery, just as there are with any type of surgery. There is a 1 to 3
percent risk of stroke following surgery. Another fairly rare
complication is the re-blockage of the carotid artery, called
restenosis. This may occur later, especially in cigarette smokers.
Numbness in your face or tongue caused by temporary nerve damage is a
possibility, but uncommon. This usually clears up in less than one month
and most often does not require any treatment.
Carotid Angioplasty and Stenting
An alternative, new form of treatment, carotid angioplasty and
stenting, shows some promise in patients who may be at too high risk to
undergo surgery. Carotid stenting is a procedure in which a tiny,
slender metal-mesh tube is fitted inside your carotid artery to increase
the flow of blood blocked by plaques. The stent is inserted following a
procedure called angioplasty, in which the doctor guides a
balloon-tipped catheter into your blocked artery. The balloon is
inflated and pressed against the plaque, flattening it and re-opening
the artery. The stent acts as scaffolding to prevent the artery from
collapsing or from closing up again after the procedure is completed.
You are awake during this procedure, and usually discharged from
the hospital the following day. Most patients are able to resume normal
activities when they get home.
There are several potential complications of endovascular
treatment. The most serious risk from carotid stenting is an embolism,
caused by a disrupted plaque particle breaking free from the site. This
can block an artery in the brain, causing a stroke. These risks are
minimized using small filters called embolic protection devices in
conjunction with angioplasty and stenting. There is also a slight risk
of stroke due to a loose piece of plaque or a blood clot blocking an
artery during or right after surgery.
Hyperperfusion, or the sudden increased blood flow through a
previously blocked carotid artery and into the arteries of your brain
can cause a hemorrhagic stroke. Other complications include restenosis
and short periods of medically treatable reduced blood pressure and
heart rate.
Although surgery may reduce your risk of stroke, it does not stop
plaque from building up. To prevent your arteries from hardening again,
the following health tips may help:
- Eat foods low in saturated fat, cholesterol, and calories
- Exercise regularly, especially cardio exercises such as
walking
- Maintain your ideal body weight
- Avoid smoking
- Discuss taking cholesterol-reducing medications with your
doctor
Before you undertake any exercise program, check with your
doctor first.