Centers for Disease (CDC) statistics show that more than 795,000 people in the United States have a stroke each year, and almost 130,000 of them die as a result. In addition to the personal suffering caused by the condition, stroke exacts a huge financial toll, costing the U.S. economy an estimated $36.5 billion annually due to health care services, medications to treat stroke, and missed days of work.
The vast majority of strokes, around 87%, are ischemic – which means they result from an obstruction within a blood vessel that supplies blood to the brain. So it seems logical that if preventive measures can be taken to stop ischemic strokes before they happen, the benefits could be enormous.
To that end, tests known as carotid artery scans have been developed in order to hopefully identify those at risk for ischemic strokes that originate from plaque-clogged carotid arteries in the neck, a condition called carotid artery stenosis (CAS). These non-invasive, ultrasound screenings are often promoted by health centers and offered at company and community-sponsored health fairs.
But a warning has been sounded by the United States Preventive Services Task Force (USPSTF) that these screenings may not be helpful for most people. In fact, carotid artery scans could actually cause more health problems than they prevent.
Benefits Weighed Against Risks
According to the USPSTF report, recently published in the American Journal of Medicine, evidence from 56 studies indicates that screening and treating people for CAS who do not have any history of a previous stroke, transient ischemic attack or other neurologic signs or symptoms can be harmful and even life-threatening.
The reason? False positive results from carotid artery scans are fairly common and can result in risky, unnecessary surgical procedures. That’s why the American Academy of Family Physicians (AAFP) has joined with the USPSTF to recommend against screening adults for asymptomatic CAS.
“The screening tests for carotid artery stenosis may be unreliable in the asymptomatic adult, so a patient may not have significant stenosis, but may undergo an intervention because the screening test was inaccurate,” Jennifer Frost, M.D., medical director for the AAFP Health of the Public and Science Division, said in a media statement. She explained that the most common treatment for CAS is carotid endarterectomy (CEA), a surgical procedure that carries significant risk for stroke, heart attack and cranial nerve injury.
In a related editorial accompanying the USPSTF paper in the American Journal of Medicine, Larry B. Goldstein, MD, from the Duke Stroke Center and Durham Veterans Affairs Medical Center, pointed out that strokes resulting from CAS in people who have no symptoms or history of stroke account for only a tiny portion of all stokes (.5% – 1%). Goldstein added that potential consumers of carotid artery scans for stenosis “should be aware that the test is unlikely to prevent them from having a stroke or to lead to improvements in their health.”
Proven Ways to Reduce Stroke Risk
While there is no longer an economical or medically sound reason to include carotid artery scans in preventive health screenings for most people, that doesn’t mean that a proactive approach to preventing strokes doesn’t work. Instead of screening for asymptomatic CAS, for example, the AAFP’s Dr. Frost recommends focusing on identifying and treating other major risk factors for stroke, especially high blood pressure.
In addition to keeping blood pressure under control, the National Institute of Neurological Disorders and stroke lists these risk factors that can be treated with lifestyle changes or medical therapy to help prevent strokes:
- Cigarette smoking causes about a two-fold increase in the risk of ischemic stroke and up to a four-fold increase in the risk of hemorrhagic stroke (caused by bleeding into the brain).
- Common heart disorders such as coronary artery disease, valve defects, irregular heart beat (atrial fibrillation), and enlargement of one of the heart’s chambers can result in blood clots that may break loose and block vessels in or leading to the brain. If heart problems are identified, they can often be treated to reduce stroke risk.
- Diabetes can cause destructive changes in the blood vessels throughout the body, including the brain. Treating diabetes and keeping blood sugar under control can prevent or delay the onset of complications that increase the risk of stroke.
- Elevated levels of low-density lipoprotein cholesterol (LDL), often called the “bad cholesterol,” can cause cholesterol to build up in blood vessels, leading to both heart attack and stroke. Diet, exercise and drug therapy, if needed, can lower LDL.
- Physical inactivity and obesity are associated with hypertension, diabetes, and heart disease – conditions that up the risk of stroke.