Screenings for Stroke in Doubt
There has been an unusual buzz around some pharmacy counters lately. Customers are lining up not only for drugs--but for on-the-spot, ultrasound stroke screenings. The pitch is hard to resist: For $49, find out whether you could be at high risk for a brain attack that half the time strikes without warning. Stroke screening with mobile ultrasound machines has been around for a few years but largely confined to special events at senior centers, corporate offices and churches. As the devices have begun popping up in pharmacies, however, some doctors are cautioning that consumers may wrongly assume that the procedure has the blessing of the medical establishment.
The handful of companies that are marketing the stroke-screening tests say that the purpose is not to diagnose disease but, rather, to identify at-risk patients--and refer them to doctors. One company, On-Site Health Screening of Redondo Beach, has screened nearly 25,000 people in the last year at pharmacies in Southern California, says company President Joel Geffen, including “a lot of people who now swear we’ve saved their lives.”
Pressing a probe against the neck, a trained technician looks to see whether any plaque has accumulated on the walls of the main artery feeding the brain--the carotid. Researchers have shown that a thickening of artery walls is associated with elevated stroke risk, even in people with no history of vascular disease.
Still, stroke specialists have mixed feelings about the scans. They agree that the tests, which take five to 10 minutes, can help identify people at high risk of a future stroke. But the results may also cause undue anxiety in people who actually are in good health.
Such off-the-street scans typically find that anywhere from 5% to 20% of clients have an elevated risk of stroke. But the actual number of patients needing treatment is closer to 2% or 3%, said Dr. Julio Chalela, a stroke neurologist at the National Institutes of Health.
The presence of some plaque in the carotid by itself doesn’t mean much: By age 50, most healthy adults will have something detectable there.
“That is what I worry about,” he said. “There’s a psychological cost paid by people who are told they are at elevated risk, and they’re very scared--often for no reason.”
Health insurers generally do not pay for carotid ultrasound tests in patients without clear symptoms, such as a prior stroke. There is a sound reason for that, doctors say: There is no clear evidence that doing the tests in healthy people actually reduces the number of strokes.
Also, doctors attribute only about 25% to 30% of all strokes to blockages in the carotid, Chalela said. “The segment in the neck is the place where we most commonly see problems, so that’s a good place to look,” he said. “But that’s not going to tell you anything about what’s happening elsewhere.”
Few, if any, of the outfits doing off-the-street scans are certified by a major accrediting organization, said Sandra Katanick, executive director of the Intersocietal Commission for the Accreditation of Vascular Laboratories.
“There’s a lot of variation between operators reading the results of these tests, so you might get different results from person to person,” Katanick said. “We have no way of knowing how good the operators are if we don’t accredit the lab.”
In short: A quick screen for stroke is a very crude measure of risk and should be treated as such.
“We make sure to tell people we’re just looking at their carotid, that we’re not doctors, that we don’t diagnose; we’re very careful not to cross the line,” Geffen said. “If there’s significant plaque there, we tell people very calmly to take it to their doctors to review the results, and their doctors can make the decision.”
If there is evidence of significant blockage, doctors almost always refer the patient for a more in-depth ultrasound test, at an accredited laboratory.
If that test confirms the finding, doctors often recommend lifestyle changes, such as improved diet and more exercise, and may prescribe plaque-reducing drugs.
Only in severe cases do doctors recommend surgery to remove the plaque. Only about 1% of people--or less--in the general population would benefit from the surgery, Chalela said.
For those tempted to spend $40 to $50 on an off-the-street scan, doctors recommend three things:
Ask about the experience of the operators; a technician ought to have trained at a hospital with a radiologist or a registered vascular technologist. Make sure they don’t actually give diagnoses. And make sure they aren’t referring customers to one particular doctor. “If they’re recruiting for one particular doctor or practice,” said Dr. Wesley Moore, a vascular surgeon at UCLA, “clearly there’s an ethical problem with that.”
Otherwise, he said, it’s a personal decision about risk. Americans suffer about 600,000 to 700,000 strokes each year, and half of them hit without warning, according to the National Stroke Foundation.
“So I’d understand if my dad wanted to spend 50 bucks and do it,” Moore said.
“I’d say fine. If they do the test and find no disease, then he’s reassured. If they do find something, and they refer him for further testing, that’s fine, too--as long as they don’t infer anything more based on this crude test.”
