Carotid Artery Stenosis and Stroke, Part 2

Someone asked me to wrote more about carotid artery disease, so here goes.  We see a large number of patients with carotid artery stenosis.  Next to aneurysms, I don’t think that there is any other medical condition that raises more anxious feelings for patients.  The paired carotid arteries supply  the left and right side of the brain.  There are ale smaller arteries that supply the back of the brain named the vertebral arteries, and there is a communication between the 2 systems within the brain called the Circle of Willis.  But the dominant supply to each side of the brain is via the carotid artery.  Blockages in the carotid artery can lead to strokes.  The typical symptom of a stroke are loss of motor control on one side of the body versus the other, loss of speech ability, and loss of vision in one eye versus the other.  Stroke symptoms do not cause pain, and vague symptoms such as dizziness and vertigo are not typical of strokes (unless it occurs in a certain area of the brain that control balance).

The typical risk factors for carotid artery disease are the same as for other cardiovascular diseases, namely cigarette smoking, high blood pressure, high blood sugar, high cholesterol, age and family history. Age and family history you are stuck with.  If Dad or Mom had heart disease and strokes at an early age, then unfortunately you are probably at a higher risk.  But the other risk factors are able to be controlled with medication if needed, or diet and exercise and smoking cession.

Most people with carotid artery disease never have symptoms.  In general, the higher the degree of narrowing, the greater the risk of symptoms.  Sometimes, you can have what is called a Transient Ischemic Attack (TIA) or mini-stroke, and at other times you might have a full blown stroke.  The difference between the two is that a TIA resolves within 24 hours, while a stroke last greater than 24 hours.  We don’t know which event is going to occur, if it does occur. We just know if you have a TIA, and you have significant carotid artery narrowing, your risk for a full blown stroke is a lot higher.

Most patients with carotid artery stenosis do not need surgery.  We emphasize controlling the risk factors, as well as smoking cessation.  I advocate an anti-platelet agent such as Plavix or aspirin, and close follow-up.  We used to be much more aggressive with carotid stenosis in terms of surgical management years ago.  However, in the era of anti-platelet agents such as Plavix, as well as statin drugs to control cholesterol level, and much better management of diabetic patients by our family practice and medical colleagues, the role for carotid artery intervention has diminished.  The options for management of carotid stenosis include carotid surgery where the blockage is cleaned out versus carotid artery stenting where the blockage is essentially reopened with a stent.  There is an ongoing debate about which technique is better for patients.  I suspect the answer is going to be dependent on the patients age, and anatomy, as well as other cardiovascular issues such as heart disease.

I dont think there is any doubt that if you have a TIA or a stroke with good recovery, and you have severe carotid artery narrowing on the side of the stroke, that you would benefit from carotid artery intervention to reduce further strokes.  What is less settled to me in the modern era is what should be done for patients with moderate to severe carotid artery disease (greater than 60% narrowing) who do not have symptoms of TIA’s or strokes.  There are carotid stents or carotid surgeries being performed for that condition (so called asymptomatic carotid stenosis), but the data is not clear in my mind of the benefits of the intervention versus the risks.  Thats what this whole business is about, balancing the risks versus benefits of every intervention we do.