Feeling perfectly healthy? Chances are, your doctor still orders certain tests—called “screening tests”—that check for conditions such as colon cancer or osteoporosis that might be lurking and could be treated.

 So why not a screening test for stroke risk? We know that people living in the US have nearly 800,000 strokes each year and that 80% to 90% of those strokes are caused by blood clots. Many of these strokes originate from clogged carotid arteries—large arteries in the neck that feed blood to your brain. Like the arteries that feed your heart, these can be narrowed by plaque buildup as you age. 

This may surprise you: There is a test that can detect such blockages. It’s a simple ultrasound of your neck that costs about $70 to $300 (depending on where you live) and sometimes is covered by insurance.

However, no major medical group advises checking the carotid arteries of all adults—due to concerns that many questionable results will turn out to be wrong, leading to needless worry, costly follow-up testing and risky surgeries. 

But some medical groups, such as the Society for Vascular Surgery, the American Heart Association and the American Stroke Association, think it makes sense to test certain people who are at increased risk for a stroke from a clogged carotid artery. 

The danger: Without testing, too many people, while clinically asymptomatic, will unknowingly suffer one or more symptomless “silent strokes”—small, repeated insults to the brain caused by inadequate blood flow, which over time can lead to decline in cognitive function. Unsuspecting people with blockages also may ignore signs of  transient ischemic attacks, or TIAs (also known as “ministrokes”)—brief attacks that produce passing stroke symptoms that may last only for a few minutes, such as weakness of an arm or leg, brief loss of vision or difficulties speaking. Ministrokes can be the precursor to a bigger and permanently damaging stroke. Still other people will get no warning before a stroke that leaves them disabled or dead, further adding rationale for the screening test.

Should You Get Scanned?

While guidelines from medical groups vary, many doctors—including myself—say that you should consider a potentially lifesaving scan of your carotid arteries if one or more of the following apply to you…

A “bruit” in your neck is detected by your doctor. This abnormal sound, detected by a stethoscope during a routine physical exam, can indicate a narrowed artery—especially when it’s accompanied by other stroke risk factors, such as high blood pressure. Note: Your doctor should listen for a bruit on both sides of your neck. In some cases, patients actually can hear a “whooshing” sound in their ears.

You are over age 65 and have multiple stroke risk factors, such as smoking, elevated cholesterol, high blood pressure and/or diagnosed coronary artery disease. 

You have been diagnosed with peripheral artery disease (PAD). This narrowing of the leg arteries can cause leg pain, particularly when walking. If the arteries feeding your limbs are clogged with plaque, the arteries in your neck may be, too.

You have worrisome results from an ankle-brachial index test. With this test, your doctor compares your blood pressure readings at your ankle and upper arm. The test can indicate PAD, so it’s recommended for people with suspicious symptoms in their legs, including pain, numbness or weakness, but also is sometimes used as a broader screening tool for artery health. 

You have had symptoms of a ministroke. This might include weakness or numbness on one side of your body or slurred speech. Even if the symptoms lasted for just a minute or two, they are serious. People who have a ministroke are at high risk for a bigger stroke, most often in the first few days, but also in the months and years ahead. If you have possible ministroke symptoms in the future: Treat them as a medical emergency, and call 911 right away. 

Important: If you decide, in consultation with your doctor, to get a carotid ultrasound, make sure that you get the gold-standard test, called a carotid duplex ultrasound, from a laboratory accredited by the Intersocietal Accreditation Commission (IAC). The test, which requires no preparation, can take up to 30 to 60 minutes. You will be asked to wear loose-fitting clothing that allows the technician to access your neck. If there is significant plaque in a carotid artery, the lab report should say how extensive the blockage is and describe the characteristics of the plaque in a way that will help your doctor assess your risks. 

What’s Next?

If your carotid scan shows no significant blockage, continue taking steps to lower your stroke risk—control blood pressure and cholesterol, maintain a healthy body weight and don’t smoke. 

What if your carotid testing indicates trouble? Here are the rules of thumb…

If less than 50% to 60% of your artery is blocked and you have no symptoms, you will likely be advised to continue or add medications that reduce your stroke risk, such as a statin for high cholesterol, aspirin to reduce clotting and medication to lower your blood pressure. If you smoke, you will have a powerful new reason to quit.

If your blockage is 60% or more but you have no symptoms, surgery (called a carotid endarterectomy) to remove the plaque may be needed, depending on the severity of the narrowing and the character of the plaque…or if there has been increased narrowing over time. If surgery is not indicated, drugs and lifestyle changes are recommended, and scanning should be repeated every six to 12 months to watch for progression.  

If you have a blockage of 50% to 99% and symptoms, the choices are clearer. Unless you have a condition, such as severe, noncorrectable coronary artery disease, heart failure or severe chronic obstructive pulmonary disease (COPD), that makes such procedures too risky, endarterectomy or a stent to open your clogged artery likely will be offered. Stenting is considered more appropriate for symptomatic patients who are too high risk for endarterectomy.

Caution: These procedures can reduce your long-term stroke risk, but they both carry risks of causing an immediate stroke or death by dislodging plaque and sending it to your brain.   

My advice: If you are considering one of these procedures, look for a highly experienced surgeon and hospital—and ask for their complication rates. With a top-notch team, stroke or death rates following endarterectomy or stenting should be no more than 2% to 3% for asymptomatic patients…and no more than 5% to 6% for symptomatic patients.