Carotid Stenting Treats a Major Risk Factor for Stroke
William Rilling, MD
Medical College of Wisconsin Interventional Radiologist;
Director, Vascular/Interventional Radiology
Named one of the “Best Doctors in America®” 2004 by Best Doctors, Inc.
Last year, the Food & Drug Administration approved a new form of stent designed to specifically treat carotid artery stenosis, a disease that narrows the main arteries in the neck that supply blood to the brain. William Rilling, MD, talks about carotid stenosis and how this major risk factor for stroke can be treated through carotid stenting.
Q. What is carotid artery stenosis and what are the risk factors for developing the disease?
Carotid artery stenosis is narrowing of the carotid arteries due to a build up of plaque deposits. Plaque forms when cholesterol and cells build up in the wall of an artery. These are the same types of deposits that can occur in the coronary arteries, leg arteries and elsewhere throughout the body through the process called atherosclerosis. Although carotid artery stenosis can be an isolated condition, it is most commonly associated with people who have systemic atherosclerosis. The risk factors are the same as for coronary artery disease – high blood cholesterol, high blood pressure, smoking and diabetes.
Carotid artery stenosis is a major risk factor for ischemic stroke, the type of stroke that occurs when an artery to the brain is blocked. The disease, however, may or may not have symptoms, so it is important that people at risk for carotid stenosis be regularly screened by their family doctor. Their doctor may detect abnormal blood flood by listening to their neck arteries with a stethoscope. They would then be referred for an ultrasound examination, which can tell very accurately if there is a significant blockage. Some people with carotid stenosis may also experience transient ischemic attacks or TIAs. These are warning signs that tiny bits of the built up plaque are breaking off and temporarily clogging an artery. The symptoms for TIAs are similar to stroke, but they only last for a few minutes.
Q. What does the stent do and how is it inserted in the carotid artery?
A stent is a metallic mesh device that remains permanently in place to help keep the carotid artery open. Usually, a tiny catheter is inserted through the femoral artery at the top of the leg and threaded through the aortic arch to the carotid artery. The catheter dilates the artery with a balloon and the stent is inserted. It's similar to devices used to treat cardiovascular disease. The major difference is we now have a device specifically designed for the carotid artery. The new system includes filters or protection devices that act as a “safety net” and prevent plaque from breaking off and going to the brain – and potentially causing a stroke – while the procedure to insert the stent is being performed.
The technical success rate for performing the procedure and deploying the device is very good – about 98 to 99 percent. And the risk for a major stroke occurring during the procedure is very low – in the 3 percent range, which compares favorably with surgery by a well-trained vascular surgeon. Carotid stenting, however, should be done by a highly trained and experienced physician.
Q. Will stenting replace the need for surgery to open carotid arteries?
For some patients, surgery is still the best option. The surgical procedure is called carotid endarterectomy and basically involves making an incision in the neck and dissecting the artery. The artery is opened and plaque is removed. It's less invasive than surgeries to open arteries in other parts of the body. Patients are hospitalized for just a day or two and are back to normal activities very quickly.
Stents have been in use for years to open arteries. What is different is we now have a stent specifically designed for the carotid artery with a protective device to lower the risk of intraprocedural stroke. So patients with carotid stenosis now have a second option, especially if surgery would be risky because of other health problems such as heart or lung disease. There are also some patients who have had radiation treatment to the neck or have had other neck surgeries that would make endarterectomy more difficult to perform. And in some cases the carotid artery plaque is located higher up in the neck, almost behind the jawbone. Surgery would require disarticulating the mandible, so a stent would be a less invasive option.
Current data in regard to carotid stenting and the risk of stroke versus surgery is very promising. But there is definitely a role for both procedures. What is critical is that at Froedtert & Medical College of Wisconsin, we're working closely with the vascular surgery, neuro interventional radiology and neurology as a multidisciplinary team to determine which patients are better served by surgery, and which patients are better served by carotid stenting.