Calcium scans can help predict heart disease
For decades, doctors have relied on well-known cardiovascular risk factors to determine how patients should be treated to ward off a heart attack or stroke. These factors include high blood pressure, elevated cholesterol, diabetes, a history of smoking, obesity and a family history of premature heart disease.
When a patient has either no risk factors or many of them, treatment decisions are usually straightforward. Doctors typically tell patients with no risk factors to keep doing what they’re doing, while those at high or moderately high risk are often advised to start medications along with adopting lifestyle measures, like a heart-healthy diet and regular exercise.
But when patients are in the middle-ground of risk, or are known to be at elevated risk but resist advice to take medication or change their habits, there’s a test that can help to clarify the best course of treatment and help persuade reluctant patients to follow it.
The test is a coronary calcium scan, which takes 10-15 minutes and usually costs about $100 to $400, although it is often not covered by insurance. The test uses specialized CT X-rays to assess the presence and amount of calcium (actually bony deposits of plaque that signal atherosclerosis, or “hardening of the arteries”) in the blood vessels that feed the heart.
The radiation dose is low, about the amount in a mammogram, and calcium scores can range from zero up into the thousands. The higher the level of calcium in coronary arteries, the greater the patient’s likelihood of suffering a cardiovascular event like a heart attack or stroke within the next decade.
In 2018, the U.S. Preventive Services Task Force said the calcium test can indeed help doctors assess a patient’s cardiovascular risk. But the agency concluded there was not yet adequate evidence to show that the test’s results improved patient outcomes above what is typically recommended, based on standard risk factors alone.
Still, many doctors who practice preventive cardiology believe otherwise. They say the results of a calcium scan can pinpoint which patients would benefit from treatment to reduce their cardiovascular risk and help motivate patients to follow through, for example, by changing their diet or taking medication.
Why younger at-risk adults should care
Results of a calcium scan can also be important for younger men and women — and sometimes for their physicians, who may not take risk factors in younger patients as seriously as they should.
“Given the robust association between coronary artery calcium and cardiovascular disease, the presence of coronary artery calcium in young adults should be a red flag for a high-risk patient,” said cardiologists Dr. Sadiya Khan and Dr. Ann Marie Navar in a recent editorial on calcium scoring they co-wrote.
As Khan explained in an interview, “The presence of any calcium in coronary arteries is a sign of having heart disease.”
When atherosclerosis first starts to develop, the arterial lesions, called plaque, are not calcified, explained Dr. Philip Greenland, a preventive cardiologist at Northwestern. Rather, the lesions acquire the bony deposits over time that gradually increase when the plaque ruptures and is repaired. The healing process causes calcification, he said.
The good news, and bad news, of a zero score
Greenland said people with “a low-risk factor profile and a calcium score of zero have a kind of warranty that they won’t have a heart attack within 10 years.”
“But,” he continued, “if risk factors put you above a 20 percent 10-year risk of a cardiovascular event, even zero calcium is not sufficient to provide such a warranty.” You can determine your risk profile, which considers such factors as age, gender and race, using the calculator at cvriskcalculator.com.
Based on the Danish report, Khan said, “Having a calcium score of zero is not a get-outof-jail-free card,” especially for younger men and women, who may still be at high risk for coronary artery disease despite the absence of coronary calcium. She said in the United States, Black adults tend to have less coronary artery calcium compared to their white peers but may still be at high risk because of other cardiac risk factors.
Khan said regardless of calcium score, all patients at high risk, and especially those with symptoms of heart disease, should be treated with medication and lifestyle changes. Among helpful measures are lowering elevated levels of blood pressure, cholesterol and glucose; adopting a heart-healthy diet; getting regular physical exercise; and striving to achieve and maintain a normal body weight.