CAROTID ARTERY STENOSIS

The carotid artery, or "carotid artery," is the primary vessel carrying blood to the anterior regions of the brain. Like other arteries in the body, the carotid artery can develop plaque formation, a type of calcification known as atherosclerosis, due to calcium or fat accumulation. As plaque buildup increases, the artery narrows and loses flexibility. This process increases with age, high blood pressure, and diabetes. While the prevalence of atherosclerosis is 1% in adults aged 50-59, this rate rises to 10% in adults aged 80-89.

Symptoms

Fatty particles in atherosclerotic plaques can break away from the plaque and travel through the circulation to smaller blood vessels in the brain, causing blockages in the brain vessels. This can lead to a transient ischemic attack (TIA) or a complete stroke. The severity of symptoms depends on the blocked artery and the presence of accessory vessels supplying that area of the brain. In the event of a stroke, speech impairment, weakness, or numbness in the arms and legs may occur. Depending on which side of the brain is affected, the opposite arm or leg may experience weakness and numbness. Most people are right-handed, and the left hemisphere of the brain is the dominant hemisphere. If a blockage in the left carotid artery occurs, the patient's speech may be affected, as the left side of the brain controls speech. If the blockage resolves spontaneously, or if the reduced blood flow caused by the narrowing is restored to normal by the addition of accessory vessels or increased blood pressure, these symptoms may disappear within 24 hours. This condition is called a transient ischemic attack and may be a sign of a future severe stroke. Patients experiencing a transient ischemic attack should be evaluated by specialist physicians without delay, as the subsequent stroke usually occurs within the first weeks.

How is carotid artery stenosis diagnosed?

A patient presenting with a preliminary diagnosis of carotid artery stenosis is initially evaluated for hypertension, diabetes, high cholesterol, and smoking. Following a physical examination and necessary blood tests, a carotid Doppler ultrasound may be performed to visualize the carotid artery. CT angiography or MRI angiography may be used for more detailed examination. In rare cases where these tests are insufficient, interventional neuroradiologists may perform a detailed evaluation of the vessels using catheter angiography and perform treatment planning. As with all blood vessels, the gold standard for imaging neck and cerebral vessels and diagnosing related diseases is conventional catheter angiography.

How is carotid artery stenosis treated?

The first step in treatment is to eliminate risk factors to reduce the risk of stroke due to carotid artery stenosis. Patients may be advised to quit smoking if they smoke and to begin diet and exercise to normalize blood sugar and lipid levels. If necessary, medications to regulate blood pressure, blood sugar, and lipid levels may be initiated. Blood thinners are prescribed to prevent further plaque formation and reduce the risk of plaque deterioration and stroke. This medication regimen typically involves the single or combined use of aspirin and clopidogrel, an antiplatelet medication.

If a patient has had a stroke or transient ischemic attack due to carotid stenosis, or if carotid stenosis is severe in asymptomatic patients, drug therapy alone may not be sufficient to prevent a stroke. Stent placement and angioplasty, or open surgery and endarterectomy, can be performed to open the carotid artery and widen the vessel diameter. Carotid stenting is performed using a closed angiographic technique under local anesthesia, eliminating the need for general anesthesia. After the narrowed artery is dilated with a balloon, a stent is placed to restore the artery to its normal diameter and prevent re-stenosis. During the procedure, a special filter is placed in the artery to prevent plaque fragments from breaking off and blocking the cerebral arteries. In open surgery performed by cardiovascular surgeons under general anesthesia, an incision is made in the neck to open the artery wall and clean the interior. Comparisons of these two methods have not shown a significant superiority of one technique over the other in terms of efficacy and patient safety.