A significant portion of the blood flow to your brain comes from the carotid arteries. The common carotid arteries (CCA), located on both sides of your neck, divide into two vessels. These vessels are called the external carotid arteries (ECA) and the internal carotid arteries (ICA). The external carotid arteries bring blood to your face. The internal carotid arteries bring blood to the front part of your brain.
One type of carotid artery disease is atherosclerosis, which is caused by a buildup of fatty substances like cholesterol. These fatty buildups are sometimes called "plaque". This results in a thickening and hardening of the vessel, so that the flow of blood is slowed down. Atherosclerosis can develop in one or both carotid arteries.
Treatment options for atherosclerotic carotid artery disease include: medication, surgery and less invasive procedures such as placing a stent in the narrowed artery. Using stents in the treatment of carotid artery disease is a relatively new option for some patients. The FDA is in the process of approval for carotid artery stent therapy. Consult your physician, for information on when this technology will be available.
You may be a candidate for the procedure if you are considered high risk for conventional surgical therapy (carotid endarterectomy). Only high risk patients will be considered for carotid artery stenting until the FDA is satisfied with the long term results of this new therapy. High risk patients with a carotid artery that is significantly narrowed (usually by more than 60 percent) with symptoms of a mini stroke or stroke are potential candidates. High risk patients with no symptoms, but with an 80% narrowing of the carotid artery may also be candidates for the procedure. You may also be a candidate if you have developed a new narrowing after previous carotid surgery.
A life expectancy shorter than 2 years
An irregular heart rhythm
An allergy to any of the medications used in the procedure
Bleeding in your brain within the last 2 months
Complete obstruction of the carotid artery
A stent is manufactured in one of two different configurations. The first type is called a balloon expandable stent. The stent is securely mounted on a balloon catheter and the catheter is advanced to the level of the narrowing. The balloon is then inflated which presses the stent against the vessel wall. The balloon is then deflated and the catheter removed. The second type is called a self-expanding stent. This stent is "spring-loaded" into a catheter and is secured to the catheter with an overlying sheath. The stent and catheter are advanced to the level of the narrowing, and once positioned, the sheath is pulled back allowing the stent to expand. The stent will expand to the normal size of the vessel. The catheter is then removed. The musculature of the vessel holds the stent in place. After a period of time, the vessel forms a cellular layer over the stent, so the stent basically becomes a part of the vessel. Because stents are made of stainless steel or metal alloys, they resist rust.
Prior to your procedure you will be asked to undergo the following tests or procedures to evaluate your condition and determine the location of the narrowed artery:
History and Physical Examination
Imaging (CT, MRI, MRA)
An angiogram is an x-ray procedure that studies the blood vessels in the body. Contrast media (a liquid dye that may be seen on x-rays) is injected into a vein or artery, and x-ray pictures are then taken in rapid succession. The series of pictures reveals the size and shape of veins or arteries and vessel abnormalities.
Prior to the carotid stent procedure, the nurse will give you some medication through the intravenous line that is placed in your arm to help you feel relaxed and sleepy. The Interventional Radiologist will also inject a local anesthetic in your groin area where the catheter will be inserted. He/she will then make a small puncture in your groin to access the femoral artery in your leg. A thin tube called a catheter is then introduced through the artery and advanced to the affected artery under x-ray guidance.
Before inserting the stent, the Interventional Radiologist 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 this point in the procedure, the Interventional Radiologist may perform a balloon angioplasty at the blockage site. A balloon catheter is similar to a regular catheter, but it has a small balloon mounted on its tip. The Interventional Radiologist inflates and deflates the angioplasty balloon to flatten the plaque and widen the space where the blood flows through.
The Interventional Radiologist will then exchange the balloon catheter for a stent delivery catheter. The Interventional Radiologist will direct the stent delivery catheter to the narrowed area and deploy the stent. The stent pushes the plaque against the side of the vessel, thereby opening the vessel.
The stent delivery catheter and any embolic protection devices are then removed. The stent remains permanently in your carotid artery.
After the procedure, the catheter will be removed and the puncture site manually compressed for about 20 minutes to prevent bleeding. After the procedure you will need to lie in bed for 5 to 6 hours. You should plan to spend one night in the hospital for observation. More specific post-procedure instructions will be given to you prior to your discharge.