There are two large arteries called carotid arteries situated in either side of the neck. They are responsible for the majority of the blood supply to the brain. On each side, the common carotid artery (left and right common carotid arteries) branches into two arteries:
Atherosclerotic disease commonly affects the area where the common carotid arteries branch out (carotid bifurcation). These atherosclerotic plaques deposited over the inner surface of the artery causes narrowing (stenosis) of the vessel.
TIA occurs when there is an occlusion (closure or blockage) of the blood vessels supplying the brain with oxygen.
Due to the lack of blood supply and therefore oxygen reaching the brain, ischaemia occurs to the brain cells for a short period of time.
When a blood vessel gets obstructed, the body will try to correct it through one of the following methods:
If the salvage is successful, the neurological symptoms experienced by the patient will be temporary. These symptoms can include:
In a TIA, these symptoms usually resolve within 24 hours.
Stroke is the third most common cause of death and the leading cause of disability in many developed countries.
In a stroke, the body is unable to correct the occlusion (closure or blockage).
This results in permanent brain cell death over the region of the brain where the occluded blood vessel supplies.
The symptoms of a stroke are similar to a TIA but they persist beyond 24 hours.
Occlusion of a major blood vessel in the brain will result in a large area of brain cell death and could be fatal or severely disabling.
Patients' disability after stroke can be improved by rehabilitation exercises as the surrounding viable brain will take over part of the work of the affected brain cells.
A duplex ultrasound is able to measure the velocity of blood flow in a vessel.
It is a painless and non-invasive test that effectively:
Both these tests serve as "second line tests" particularly for planning treatment.
Computed tomography angiogram uses a CT scan to obtain detailed images of the blood vessels once a contrast medium (dye) is injected through a thin, long tube (catheter) placed in a vein in the arm. As the dye flows through the blood vessels, the CT scan takes images.
Magnetic resonance angiogram uses the same concept except that in this case, a magnetic resonance imaging (MRI) machine is used instead of a CT scan.
Carotid angiogram is considered the standard test to diagnose and measure the severity of carotid artery disease.
This is an invasive procedure that requires an artery in the groin area to be punctured.
A long thin tube (catheter) is inserted into the punctured groin artery and guided into the carotid artery by using X-ray imaging.
The treatment for carotid artery disease cannot reverse the stroke event if it has already happened. However, it is aimed at preventing stroke by means of:
Internationally, carotid surgery is still superior to carotid endarterectomy.
Carotid angioplasty is usually performed when it is not possible to do carotid surgery.
This includes previous surgery or radiotherapy in the neck.
The procedure is usually done under sedation and/or local anaesthesia and sometimes general anaesthesia. It involves the insertion and inflation of a small balloon in the occluded artery to widen the area, as well as putting a stroke-protection device during the procedure to minimise complication.