Diseases And Conditions

Carotid stenosis

Carotid artery stenosis refers to narrowing of the large arteries of the neck supplying blood to the brain. Overtime, accumulation of blockage can occur, with clots forming in these arteries and breaking off to travel to the brain or blocking the artery completely. The result can be a severe stroke. Sometimes a TIA or mini-stroke may occur.

CAS is caused by the same conditions that cause blockages elsewhere in the body, like the heart and the legs. In fact, blockages in these arteries are usually seen together. When blockages in the arteries occur, it’s referred to as atherosclerotic disease or arteriosclerosis. Arteriosclerosis is caused by high cholesterol, high blood pressure, smoking and diabetes. The symptoms from arteriosclerosis usually depend on the organ or structures that are affected by the lack of blood supply.

When CAS develops, the risk of stroke is significant, but depends on the degree of narrowing and whether or not symptoms have been present. Patients with a 50% to 75% blockage have up to a 15% risk of stroke within 5 years if there have been no previous symptoms and up to a 26% risk of stroke in 5 years if TIA or stroke symptoms have been present in the past. With a greater than 75% blockage, the 5 year risk of stroke increases to 19% in patients without symptoms and 27% if symptoms have been present. It is important to note that in patients with no previous symptoms, some of the risk of a subsequent stroke may come from sources other than the carotid artery, such as the heart or the microscopic arteries of the brain. In addition, due to common risk factors, some patients may exhibit more than one type of stroke. Despite this, in patients with no previous symptoms and 60% to 99% narrowing of the carotid artery, the 5 year risk of stroke due to CAS is still about 10%.

The first line of treatment for stroke prevention, whatever the cause, is treating risk factors like heart disease, high cholesterol, high blood pressure, smoking and diabetes. In addition, studies have shown a clear benefit favoring surgery for symptomatic carotid disease >50% and asymptomatic narrowing of >60%. Surgery in this case involves opening the neck and removing the blockage from the artery, then sewing it closed. This is referred to as carotid endarterectomy. An alternative method that has recently become available is carotid stenting. In the stenting procedure the surgeon makes a small skin nick in a groin artery and navigates a device called a stent to the carotid artery. The stent is delivered, opening and expanding the blocked carotid. No surgery in the neck is required. Los Angeles Brain and Spine Institute physicians have performed the highest numbers of this procedure in the San Fernando valley of California and have participated in several clinical research trials studying the safety and effectiveness of carotid stenting.