Carotid arterial stenting (CAS) is a minimally invasive endovascular interventional procedure
The carotid arteries are the large blood vessels located on each side of the neck that carry blood to the brain. A blood clot or atherosclerosis (cholesterol build-up) in a carotid artery can decrease blood flow to the brain or even completely cut off the blood supply resulting in a stroke. Conventional treatment of carotid stenosis over the past 50 plus years has involved a surgical procedure called an endarterectomy. However, some patients are not eligible for this surgical procedure and the development of the endovascular carotid stenting procedure has become an important alternative treatment option. During a carotid stenting procedure a filter device is placed beyond the carotid stenosis to capture any debris that might break off during the procedure. Clinical research trials have shown that the use of such a filter is key in decreasing strokes associated with carotid stenting procedures. A mesh tube called a carotid stent is then placed in the artery at the site of the narrowing and expanded to open the artery.
Carotid artery stenosis, also called carotid artery disease, is a narrowing of the carotid arteries. This narrowing may lead to partial or complete blockage of one or both of the carotid arteries, causing a stroke. A stroke is a life-threatening event in which the brain’s vital supply of blood and oxygen is disrupted.
Carotid artery stenosis occurs due to narrowing of the arteries from a gradual build up of plaque. Plaque forms when cholesterol, fat and other substances line the inside walls of the arteries and build up over time causing a blockage.
You may have some of the following symptoms or you may not have any symptoms at all.
- Blurred vision
- Weakness on one side of body
If you are experiencing one or more of the above symptoms, it is important to seek medical advice immediately for an evaluation. Because some people may not have symptoms at all, it is important to schedule regular physician appointments with your doctor.
Your doctor may hear an abnormal sound over your carotid artier when listening with a stethoscope. This is called a bruit (broo’-ie). The doctor may order a carotid artery ultrasound. This non-invasive diagnostic test takes images of the blood flowing through the arteries and it can detect narrowing from plaque.
The most common way to diagnose carotid artery stenosis is with angiography. This test feeds a catheter from your groin, through your aorta and into the carotid artery. An injectable contrast dye is then inserted into the artery while images of the area are captured. This dye allows your doctor to view the arteries in a more enhanced field of view to detect any stenosis or narrowing.
The procedure usually takes place in an angiography suite or catheterization lab. Before the procedure begins, your physician will connect you to a monitor that shows your heart rate and blood pressure. During the procedure, your physician will likely talk with you and may instruct you to squeeze a small toy or ball so that he or she can monitor your brain function. While some physicians may perform the procedure under general anesthesia, in most instances, the procedure is performed while you are awake and alert. Your physician will give you medications such as heparin to prevent clots, atropine to reduce the chances of your heart slowing down, and a local anesthetic to numb the catheter insertion area. Your physician may not give you any other medications so you will be alert to follow instructions during the procedure. Your physician then locates the narrow areas in your arteries by injecting a dye into your arteries and taking live x rays, called fluoroscopy. The dye does not allow x rays to pass through, so physicians can see your arteries and use the live x rays to guide them to the blockage.
Before inserting the stent, your physician will usually perform angioplasty. In angioplasty, your physician inserts a long, thin tube called a catheter with an attached balloon into a small incision or puncture over an artery in your arm or groin. Your physician guides the catheter to the blockage site in your carotid artery using live x ray imaging. You will not feel the catheters as they move through your arteries because there are no nerve endings inside your arteries.
At this point in the procedure, your physician may insert a small balloon, basket, or filter called an embolic protection device. This device helps to prevent strokes by catching the clots or debris that may break away from the plaque during the procedure.
At the blockage site, your physician inflates and deflates the angioplasty balloon to flatten the plaque and widen the space where the blood flows through. After the artery is open, your physician then removes the catheter with the balloon attached.
Using another catheter, your physician guides a compressed stent to the same area in your carotid artery. Once the stent is in place, your physician releases it. The stent then expands to fit the artery. In most cases, your physician then uses a balloon catheter to further expand the stent.
Your physician then removes the stent-carrying catheter and any embolic protection devices. Stents remain permanently in your carotid artery. Because stents are made of stainless steel or metal alloys, they resist rust.
Carotid stenting usually takes about 1-2 hours but may take longer in some circumstances.