A carotid artery stent is used to prevent a stroke by propping open a major artery that supplies blood to the brain, according to MayoClinic.com. There are two carotid arteries on each side of the neck and when they clog or narrow, they can cause a stroke. So doctors insert a tiny balloon into the narrowed carotid and then inflate it to widen the artery. Then they insert a metal tube called a stent to keep the artery open.
Stroke Risks
Though it is meant to prevent a stroke, the procedure to implant the stent can actually cause one, according to MayoClinic.com. Blood clots can form on the equipment used in the procedure and then travel to the brain, causing a stroke. Blood thinners are used during the procedure to reduce this risk. The equipment can also knock loose the fatty deposits that are narrowing the arteries and these too can travel to the brain and cause a stroke. Long after the procedure is over, blood clots can form inside the stent, according to MayoClinic.com. If these clots break loose and move to the brain, they can cause a stroke or even death. This occurs in up to 2 percent of patients with stents, according to the National Heart, Lung and Blood Institute. Doctors normally prescribe aspirin, clopidogrel or other drugs to minimize this risk.
Bleeding Risk
During the procedure, a thin tube called a catheter is inserted in an artery in the leg and then pushed up through the blood vessels to the carotid artery to place the stent. This can cause bleeding in the leg where the catheter was inserted, according to MayoClinic.com. This is not normally serious and may just cause a bruise. But sometimes severe bleeding occurs and a blood transfusion or surgery may be required to fix it.
Artery Blockage
Sometimes the benefits of the procedure do not last long and the carotid artery narrows again, according to MayoClinic.com. Symptoms may return and the risk of a stroke will increase. This can happen within months. Stents were designed to reduce this risk, but they can't eliminate it. Some stents are coated in drugs that help reduce this risk, but they may increase the risk of blood clots, according to the National Heart, Lung and Blood Institute.
Other Risks
The procedure to insert the stent, called angioplasty, carries some other risks, according to the National Heart, Lung and Blood Institute. There is a risk of infection at the site where the catheter is inserted, and sometimes the catheter can damage blood vessels. Also, a dye that shows up on X-rays is used during the procedure to help doctors see where to place the stent. This dye can cause allergic reactions and damage to the kidneys.
