The Carotid Artery
Anatomy and physiology – what is the carotid artery and what does it do?
The common carotid artery carries blood from the heart to the brain. The main blood vessel exiting the heart is called the aorta.
The common carotid artery is a branch off of the aorta and travels up the neck. Halfway up the neck, the common carotid branches into the internal and external carotid arteries. The internal carotid artery is the branch that eventually supplies the brain with oxygen-filled blood. There is a left and right carotid artery.
Atherosclerosis is a disease that describes the formation of plaque on blood vessels. Plaque is composed of cholesterol, calcium, and fibrous tissue. When it settles on the wall of the artery, the artery stiffens and narrows. Carotid stenosis is the term used to describe the narrowing of the carotid artery.
As the stenosis progresses, blood flow to the brain becomes compromised. Carotid stenosis can lead to stroke and mini-strokes, also called transient ischemic attacks (TIA’s) in two ways, by narrowing the artery as described above or via an embolus.
An embolus is a piece of plaque that was flicked off by the main plaque or a piece of clot that settled on the plaque and then migrated. The embolus gets carried away by the circulation of blood and eventually lodges into a smaller blood vessel in the brain, denying oxygen to a part of the brain and causing the stroke.
Many surgeons will recommend surgery to remove the plaque in the carotid artery when you have been found to have significantly advanced carotid stenosis putting you in danger of having a stroke or TIA.
Who is at risk?
Atherosclerosis has been linked directly to smoking and high cholesterol. In addition, diabetes and obesity are also associated with a high risk of developing atherosclerosis.How is it diagnosed?
Carotid stenosis can sometimes be detected by physical exam. When your physician holds the stethoscope against your neck, they may hear a “bruit” or sounds of turbulence in your artery. The diagnosis can be confirmed with an ultrasound of the blood vessels.
If the results of the ultrasound are not conclusive a CT scan, MRA (magnetic resonance arteriography) or an arteriogram may be recommended by your physician.
How do I prepare for surgery?
Blood samples will be needed as well, as an EKG and chest X-ray. Depending on your health and medical history, your doctor may recommend a cardiac stress test to determine if your heart can withstand the stress of an operation. If you have lung disease, your doctor may also suggest tests of pulmonary function to help the anesthesiologist manage your lungs while you are under general anesthesia.
How is the surgery performed?
The surgery is usually performed under general anesthesia. Some surgeons do perform “awake” carotid endarterectomies if you have other medical problems that put you at high risk for surgery and general anesthesia. During an awake procedure, your surgeon will limit the amount of pain you feel by infusing local anesthesia under the skin. The benefit of having you awake during surgery is that your surgeon can check on you from time to time to make sure you are not experiencing an adverse reaction from having your artery clamped.
An incision will be made along your neck from the angle of the jaw down to the base of the neck. A clamp will be placed on the carotid artery temporarily preventing blood flow to your brain. Your brain will receive blood flow from the carotid artery on the opposite side where your surgeon is working. Then, the carotid artery will be opened. The plaque will be removed. The cut in the artery will then be sewn with a patch.
Potential Complications of Surgery
Most patients tolerate the surgery fairly well. Factors that increase your risk of developing a complication include high blood pressure that is not well managed, blockages in the carotid artery on the opposite side of where you are having surgery, and any history of a recent heart attack.
The earliest complication that could occur is bleeding under the skin that causes a blood clot. If you experience a significant amount of bleeding, the blood under the skin can push aside other structures in the neck, such as your windpipe. This would require an immediate trip back to the operating room to drain the blood. Another serious complication is that of a stroke. The risk is very low ranging between 1 and 3 percent.
Finally, re-blockage of the artery is another uncommon but possible complication, particularly if you have not modified any of the risk factors of atherosclerosis, such as smoking and a high fat diet. This complication if it occurs happens months to years after surgery.
What to expect after surgery?
You will be admitted on the day of surgery and watched closely overnight for any signs of bleeding or a stroke. Some surgeons will leave a temporary drain in your neck to catch any bleeding that might occur. This drain will be removed in the morning. Generally, patients are discharged the day after surgery.