Carotid stenosis refers to a dangerous narrowing of the inner portion of the internal carotid arteries, the two large arteries in the neck which provide the largest portion of the blood supply to the brain. The most common cause of carotid stenosis is atherosclerosis. Narrowing of the carotid artery is diagnosed with carotid duplex ultrasound.
A study performed in 1998, the NASCET (North American Symptomatic Carotid Endarterectomy Trial) study, determined that patients who had symptoms such as a TIA or ministroke and more than 70% narrowing of the internal carotid artery, had a three-fold reduction in the risk of stroke if they were surgically treated with a procedure known as carotid endarterectomy.
People with borderline stenosis (50-69% occlusion of the carotid arteries) must be followed closely by a doctor in order to evaluate whether surgery needs to be performed in the future.
The two most common treatment options for carotid stenosis are the following:
Carotid EndarterectomyThis is a procedure by which a surgeon gently removes the atherosclerotic plaque that prevents normal blood flow through the affected internal carotid artery. The plaque is removed in one piece in order to prevent the formation of small fragments that could migrate to the brain and cause a stroke. Multiple studies have determined that this is the safest way to treat symptomatic carotid stenosis.
Potential Complications of Carotid Endarterectomy
Like most surgeries, carotid endarterectomy carries a small risk of bleeding and infection. Because the surgery is performed inside the very vessels that bring blood to the brain, there is also a small risk of stroke. A risk of having a heart attack during or after the surgery also exists, and this can be a major risk for people with advanced heart disease.
Most of the risks of the surgery are low, especially if the surgeon is experienced with this type of surgery.
Percutaneous Treatments of Carotid Stenosis: Two OptionsIn this type of procedure, a thin wire called an angiography catheter is inserted into one of the large blood vessels in the groin, and is slowly advanced across the blood vessels all the way into the carotid artery where the stenosis, or narrowing, is located. Once there, the area that is narrowed can be expanded either via angioplasty or stenting (see below). Percutanous procedures have some advantages over carotid endarterectomy because they are less invasive, and because they can be performed under local anesthesia. However, because many studies have shown that carotid endarterectomy is a safer procedure in most patients, most medical centers reserve percutaneous treatment of carotid artery stenosis for patients who have a significant risk of death from carotid endarterectomy surgery.
People who should get percutaneous treatments instead of carotid endarterectomy surgery include patients who have advanced heart disease or who have had radiation therapy of the neck during cancer treatment. People who have had a previous neck surgery should be considered for a percutaneous procedure instead of carotid endarterectomy surgery. There are two main percutaneous interventions that are currently performed for carotid stenosis:
- Carotid Angioplasty: In this procedure, the angiography catheter has a small deflated balloon connected to its tip. Once the catheter is advanced to the area of the carotid where the stenosis is located, the balloon is slowly inflated causing the narrow portions of the vessel to expand. Normally carotid angioplasty is performed along with stent placement.
- Carotid Stenting: Carotid artery stenting is a relatively non-invasive procedure by which a stent (a metal mesh-like tube) is placed over the atherosclerotic plaque in order to stabilize it and allow for better blood flow.
Potential Complications of Percutaneous Treatments Percutaneous procedures can accidentally dislodge fragments of plaque and cause an embolic stroke. Catheter manipulation can lead to rupture of the artery and cause serious bleeding. There is also a small risk of infection.
Carotid angioplasty has an extremely high rate of re-occlusion which has been reported in up to 15 percent of people. Five percent of people may also be affected by carotid dissection. Carotid artery stents can sometimes cause the formation of blood clots. In those cases, carotid endarterectomy may not be possible to repair the damage. Intensive research is currently being performed in order to generate equipment and techniques that avoid these complications.
Jean-Louis Mas et. al., Endarterectomy versus Stenting in Patients with Symptomatic Severe Carotid Stenosis, New England Journal of Medicine 2006 Volume 355:1660-1671
James P Greelish, MD, Emile R Mohler, III, MD and Ronald M Fairman, MD. Carotid endarterectomy in symptomatic patients In: UpToDate, Rose, BD (Ed), UpToDate, Waltham, MA, 2007.