Stroke is the third-leading cause of death in America, and carotid artery stenosis—also known as carotid artery disease—is one of the leading risk factors for stroke, accounting for about 20 percent of strokes.
To mark National Stroke Month in May, we asked University of Minnesota Health Neurosurgeon and Neurointerventionist Ramachandra Tummala, MD, to tell us five things we should know about carotid artery stenosis and its link to stroke risk.
Carotid stenosis occurs when buildup begins blocking blood flow.
Stenosis is a medical term for narrowing of blood vessels in the body due to a buildup of inflammatory substances and cholesterol deposits—called plaque. Two carotid arteries in the neck carry most of the blood flow from the heart to the brain. When stenosis occurs in these arteries it is known as carotid artery stenosis.
Carotid artery stenosis can lead to a stroke.
Patients with carotid artery stenosis are at increased risk for a stroke, which can lead to disability or death. Sometimes, strokes can be mild and recoverable. In other instances, strokes are very large and devastating. Carotid stenosis can cause a stroke in two ways. Often, plaque lodged in the carotid arteries comes loose and goes downstream into the blood vessels in the brain, where it blocks blood flow. We call that an embolism. The other less common cause is when the carotid artery blockage becomes so severe that it actually slows down the blood flow to the brain.
If there is blockage in the carotid arteries, it’s likely the patient has buildup in other arteries throughout the body. Certain risk factors, like high blood pressure, diabetes, smoking, obesity, an unhealthy diet and a sedentary lifestyle, can put patients at greater risk for carotid artery stenosis. We call these modifiable risk factors because they are factors a person can partially or completely control. Other risk factors include age, family history, and genetics. We call these non-modifiable risk factors. In general, heart risk and stroke risk largely follow one another. Good heart health practices can help reduce carotid artery stenosis—and therefore stroke risk.
Plaque buildup occurs in every adult. But not all plaque buildup will restrict blood flow through blood vessels or cause an embolism. The older you are, the higher the risk for buildup. Men are more likely to experience plaque buildup than women.
There are two types of carotid artery stenosis: symptomatic and asymptomatic. The former is more important because there’s a higher risk of stroke. Asymptomatic narrowing carries less stroke risk. Sometimes, the stenosis can be detected by a primary care provider before symptoms occur. Patients may experience stroke-like symptoms, such as with a transient ischemic attack (sometimes referred to as a mini-stroke). These symptoms can include sudden numbness; trouble speaking or seeing, dizziness, weakness on one side of the body, weakness on one side of the face or a severe headache.
Treatment is individualized based on whether the person is symptomatic or not, the severity of the stenosis, the person’s age and health history. Another more severe health concern, like lung cancer, may also impact the treatment approach. For example, asymptomatic carotid stenosis may not be a priority if the patient has severe medical problems, such as an active cancer or heart failure.
Based on those factors, there are three possible ways to manage the disease: