For-profit companies often send offers for "potentially lifesaving" health screening tests through the mail. But the cardiovascular tests these companies perform come without objective advice from a physician and may be worthless, according to the May 2016 Harvard Heart Letter.
Tests to look for early signs of heart disease, stroke, and other diseases have a lot of intuitive appeal. But such screening tests are never 100% accurate, so they can lead to false positives — that is, their results may suggest that a disease might be present, but follow-up tests show that it isn't. That additional testing may add cost and stress, and in some cases, cause harm. On the flip side are worrisome false negatives — when the tests fail to detect a disease that actually is present.
Commercial screening companies advertise their services through the mail and on websites. The actual testing is often performed in churches or community centers, although some companies have their own fleet of mobile screening vans. But experts say that anyone considering such testing should proceed with caution.
The lack of discussion and guidance from a physician is the main thing that concerns doctors about these stand-alone tests. "Screening is all about the context," notes Dr. J. Michael Gaziano, a chronic disease expert at Harvard-affiliated Brigham and Women's Hospital. A test that might be advisable for one person because of risk factors and health status won't be advisable for another with a different profile, says Dr. Gaziano. The interpretation of the results and the kind of follow-up needed will vary, too.
In addition, most cardiovascular screening tests don't even make sense for most healthy people, according to the U.S. Preventive Services Task Force (USPSTF), an advisory group of experts that draws up guidelines for physicians about such testing. The one exception is screening for an abdominal aortic aneurysm, a bulge in the vessel that carries blood away from the heart to the rest of the body. The bulge may enlarge slowly over time and burst with little warning, leading to dangerous — often fatal — bleeding in the body. Older male smokers face the highest risk, which is why men ages 65 to 75 who have ever smoked should undergo a one-time ultrasound test to check for this condition. (Smoking at least 100 cigarettes over the course of a lifetime qualifies a person as an "ever" smoker.)
But the USPSTF discourages screening for carotid artery stenosis, which occurs when fatty deposits build up and narrow the arteries that run up either side of the neck and supply blood to the brain. Not only is this condition very rare, occurring in only about 0.5% to 1% of the population, the ultrasound screening tests produce a high number of false positive results. That triggers a cascade of follow-up invasive tests and other procedures that can cause serious harm, including a heart attack or stroke.
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