There are two carotid arteries on each side of the neck which carry oxygen-rich blood to the brain. In Carotid artery disease or carotid artery stenosis there is narrowing or blockage of the carotid arteries due to accumulation of fat and cholesterol over a period of time called atherosclerosis. These results in a material called plaque. In severe cases there can be a complete occlusion of the carotid artery.
As the narrowing in the carotid arteries takes place over a prolonged period of time, there may no symptoms till a Transient Ischaemic Attack (TIA) or a stroke happens. A transient ischemic attack also called a "mini-stroke" is a warning sign of an impending stroke & is a medical emergency. It occurs when a blood clot temporarily blocks a carotid artery which supplies blood to the brain. Hence the symptoms are temporary and may last a few minutes to a few hours. A TIA increases the risk of subsequent stroke by upto 10 times.
When the blood flow through the carotid arteries is diminished it can lead to a stroke or a “brain attack”. In a stroke there is a lack of blood supply & oxygen to the brain. When this occurs for more than 3-4 minutes, the brain starts to die.
A stroke can occur if:
• The caliber of the carotid artery becomes extremely narrowed
• There’s a rupture in a carotid artery that has pre-existing atherosclerosis
• A piece of plaque breaks off and migrates to one of the smaller arteries supplying the brain
• A blood clot forms and obstructs the carotid artery
Symptoms of carotid Artery Disease:
• Sudden loss of vision or blurred vision in one or both eyes
• Weakness and/or numbness on one side of the body, either in an arm, face, or leg.
• Slurring of speech, difficulty talking, not comprehending others conversations
• In coordination, loss of balance, difficulty in walking
• Dizziness, confusion, memory disturbances, headache,
• Difficulty in swallowing
How is carotid artery disease diagnosed?
It
is important to see your doctor regularly for a physical. He may detect
an abnormal sound, called a bruit on the neck which may signify carotid
artery disease. This results from turbulent blood flow in the carotid
artery due to the obstruction. This is a good way to screen for carotid
artery disease but it may not pick up all blockages.
Diagnostic tests include:
• Carotid
ultrasound (standard or Doppler). This test uses high-frequency sound
waves to image the carotid arteries looking for narrowing or blockages
plaques by blood clots. A Doppler ultrasound visualizes the flow of
blood through the carotids.
• Carotid
angiogram: It is an invasive imaging procedure where a catheter which
is a thin & flexible tube is inserted into a blood vessel in the arm
or leg, and guided to the carotid arteries. Narrowing or blockages can
be seen on a live X-ray screen as contrast dye is injected in the
carotid arteries. The need for treatment can then be evaluated.
• Magnetic
resonance angiogram (MRA): MRA uses a magnetic field and radio waves to
provide images of the carotid arteries in detail. This test shows the
degree of stenosis in the carotids.
• Computed
tomography angiogram (CTA): By injecting intravenous contrast dye, a
high-resolution, 3D cross-sectional image of the carotid artery can be
obtained to assess the degree of stenosis. There is some radiation
involved in this procedure.
• Computerized
tomography (CT Scan): CT of the brain produces three-dimensional (3D)
images of the brain by using X-rays. Radiological contrast material can
also be injected into a vein to view any damaged areas of the brain.
This scan is usually done after a TIA or stroke has occurred.