Written by by Carrie Applegate, CNN
A technique called cardiac calcium scan is designed to gauge calcium build-up in your arteries, looking at the chemistry of blood. This, along with healthy lifestyle choices, is supposed to provide a better outlook for those at risk of coronary heart disease.
Coronary calcium scan is a fast way to measure coronary calcium … or is it?
In practice, this test doesn’t always accurately represent cardiovascular risk factors. And at the end of the day, there’s no surer way to end up dead than experiencing a tragic coronary heart disease — the number one killer of all US citizens.
Coronary calcium scan involves a high-intensity angiogram to assess blood flow and the density of the arteries, through which blood is pumped. The computer takes thousands of pictures of coronary arteries to assess their calcium level. It’s the cerebral equivalent of a dentist’s visit.
Evaluations of coronary calcium scan can be misleading. Credit: Courtesy Ruy Guimaraes, Edith Bonebaum, Perelman School of Medicine, The University of Pennsylvania
A normal study of coronary calcium scan can show up to 200 lesions, or scars, in coronary arteries. But a recent study by the World Heart Federation (WHF) found that only 17% of coronary calcifications actually contained that much calcium. This percentage has been found to be inconsistent across different studies; even more alarming was the finding that 50% of coronary calcifications did not contain the calcium the study was specifically designed to measure.
“If the calcium in your arteries is not shaped the way doctors are estimating it, that raises questions about your ability to prevent future heart attacks,” says Alfonso Varela, vice president of patient affairs at Hospital Corporation of America, and a fellow in the clinical practice program in cardiology at the University of Pittsburgh Medical Center.
It’s unclear exactly why coronary calcium scan did not accurately show calcium in such advanced stages of disease. “We are starting to see a change in guidelines, but we don’t have a complete picture,” says Dr. Varela. “It does not mean that people with severe coronary artery disease are actually not going to have heart attacks.”
Chronic constipation? Coughing? Bedridden? Heart-related symptoms are often simply of a “dentist” variety — a mere consequence of bad health.
The fallback tool for severe heart disease is another type of ultrasound called stent placement. Cardiovascular disease can accumulate across many arteries, and the arteries that supply your heart muscle with oxygen and nutrients become hardened, narrowing the amount of blood able to reach your heart. “Stents can keep arteries open and allow blood flow back to heart muscle,” says Dr. Varela. But cardiac calcium scan, along with other risk factors, should still play a central role in assessing your heart health.
That’s not the only element of coronary calcium scan that has raised alarms. It is unclear why coronary calcium scan does not accurately show calcium in such advanced stages of disease. “We are starting to see a change in guidelines, but we don’t have a complete picture,” says Dr. Varela. “It does not mean that people with severe coronary artery disease are actually not going to have heart attacks.”
Dr. Varela and other experts have raised concerns that instead of providing an accurate indication of coronary calcium — helping guide patients and doctors toward optimal treatment — it can reinforce stereotypical fears of heart disease, sending patients to see other doctors and surgery just so their health doesn’t get stuck in diagnostic limbo.
For all the furor, the technology holds promise. It can currently be used in only about 60% of cases, but studies suggest it may be just the ticket for more effective treatment of heart attack, stroke, and other conditions in the future.
“A path to getting the benefits of coronary calcium scan without the risks is available if this is the evidence base,” says Dr. Varela. “But we still have to have significant changes in how we think of things, and a new way of thinking about things, to achieve the true potential of these tests.”