What is carotid artery disease?
The blood supply to the brain comes from four arteries. The carotid arteries are found in the front of the neck, and the smaller vertebral arteries are in the back of the neck. We receive blood and oxygen to the brain through these arteries. Any significant interruption of this blood flow can cause serious problems.
The carotid arteries arise from the major vessels of the heart, starting as the common carotid artery. This vessel splits into two branches: the internal carotid and the external carotid, just below the level of the jaw. The external carotid artery goes to the face, and the internal carotid artery supplies the brain. Once in the brain the internal carotid artery connects with an intricate system called the Circle of Willis. The vertebral arteries connect to this same system at the back of the brain. One could consider this as Interstate 285 as it circles Atlanta with the other highways joining in from the north and south. As you might expect, the “flow” of traffic on this route can sometimes cause trouble.
All of our blood vessels are subject to disease. Advancing age, cholesterol and other chemicals can cause fat deposits inside arteries which can develop into obstructions of plaque. This is what is commonly called atherosclerotic disease, or “hardening of the arteries.” There are several factors that can contribute to this process, including gender (it occurs more often in males), family history, diabetes, cholesterol levels and smoking.
As these deposits grow larger, they begin to block the flow of blood. The surface of the plaque becomes very irregular and rough and can collect clumps of cells called platelets. These clumps of platelets may suddenly break free and travel with the flow of blood. If these cells or a piece of the actual plaque break loose and briefly flow into the circulation of the brain, a transient ischemic attack (TIA) can occur. This may cause part of the body to lose function temporarily. An individual may experience weakness or clumsiness in an arm or leg. They might notice difficulty speaking. A family member may notice that there is a weakness on one side of the face. In some cases, a temporary episode of blindness in one eye may occur. Think of a window shade being pulled down over the eye. These episodes typically improve over time. However, even a brief episode of only a few minutes could be a warning sign of an impending stroke. These events should not be taken lightly. Seek medical attention if you experience these symptoms.
When episodes like this occur and do not improve, resulting in a permanent loss of function, even a small loss, then an individual has had a cerebral vascular attack (CVA), also known as a stroke. Some strokes can be caused by other problems and are not necessarily caused by carotid artery disease. Emergency medical attention is required to determine the cause and extent of the problem and begin treatment immediately.
How is carotid artery disease diagnosed?
One of the screening tests used to detect plaque inside the carotid artery is a carotid duplex scan. For this non-invasive test, ultrasound gel is applied on the neck, and sound waves are transmitted onto the artery. Like sonar on a boat, the sound waves bounce back, giving an image of the artery that can determine the speed of the blood flowing in the vessel. The velocity of the blood can indicate how much the artery is narrowing. Just like you narrow the nozzle on a garden hose to make the water come out faster, we can measure the speed of the blood and calculate how much narrowing has built up in the vessel.
When the narrowing increases significantly, then the risk of stroke begins to rise. Unfortunately, many patients do not have any warning signs to tip them off that the carotid artery is in danger. Their first hint of trouble is an actual stroke. The goal is to detect these potential time bombs and treat the problem before a stroke can occur.
Other imaging studies are sometimes used to visualize the blood flow to the brain. A Magnetic Resonance Arteriogram (MRA) is a non-invasive test that involves using a large magnetic scanner. A dye test called a carotid arteriogram can also be done. This invasive test requires placing a small catheter within the artery, and dye is injected so X-ray pictures can be taken. Fortunately, with the increasing accuracy of carotid duplex scanning, these other tests are not as common.
What can you do to prevent carotid artery disease?
When plaque builds up in our arteries, we may need to adjust our health maintenance. Since we cannot control our family history or other inherited characteristics, we should make every effort to control the other risk factors as much as possible. First, if you smoke, STOP! This is the most powerful risk factor we place on ourselves. Without going into the other health issues of lung disease and cancer, smoking will harden your arteries more than any other problem you may have. If you have diabetes, then strict blood sugar control is needed. Elevated blood sugars can cause rapid progression of disease, especially in the very small arteries. Elevated cholesterol and triglyceride levels also lead to buildup of plaque, so a low-fat diet and medication may be necessary. Since we know that clumps of cells called platelets can break free from the plaque, medications that prevent these cells from clumping together can also be helpful. Medications such as aspirin and clopidogrel (Plavix) are commonly used.
Unfortunately, despite all our efforts to control these risk factors, plaque can still build up, and more mechanical treatments are necessary. Carotid artery intervention by open surgery or stenting has been performed for many years. The safety and durability of this operation have stood the test of time. In the hands of an experienced vascular surgeon, the risk of serious complication is less than 1 percent.
Contact
The surgeons at NGPG Vascular Center can draw upon decades of expertise and the latest technology to diagnose and treat your carotid artery disease. View our vascular providers, or call 770-219-4000 to schedule an appointment.