Coronary calcium scans not beneficial for everyone
Coronary artery calcium (CAC) scans have grown increasingly popular in recent years, but new data suggest they may not be equally beneficial for all patients.
According to a new Northwestern Medicine study, CAC scans provide the greatest benefit for adults with cardiovascular risk that is considered borderline or intermediate, while adding relatively little for those already classified as low or high risk. The findings were derived from more than 6,000 adults ages 45 to 79 who participated in the Multi-Ethnic Study of Atherosclerosis and were followed for 10 years. For that study, participants received a CAC score based on a CT scan of the coronary arteries as well as a cardiovascular risk estimate using the American Heart Association’s risk calculator known as PREVENT (Predicting Risk of CVD EVENTs).
“Coronary artery calcium scans are becoming more widely available and less expensive,” study senior author Nilay Shah, MD, MPH, assistant professor of medicine in the division of cardiology at the Northwestern University Feinberg School of Medicine, noted. “Our findings suggest that not everyone necessarily needs or would benefit from a coronary artery calcium scan for the purpose of predicting risk of heart attack and stroke.”
During follow-up, about 6% experienced a heart attack or stroke. Researchers determined that incorporating CAC scores alongside standard PREVENT estimates added little benefit to risk estimation of these outcomes. The model’s ability to distinguish between patients who did and did not experience a cardiovascular event increased from 0.73 to 0.75 when calcium scores were incorporated.
However, the research team determined that the improvements in risk assessment were more prevalent among certain individuals. Researchers observed a more meaningful benefit among patients initially classified as having a 3% to 9% 10-year risk of cardiovascular disease. For these borderline- and intermediate-risk patients, CAC scores provided additional information that could help identify individuals whose actual risk was higher or lower than initially estimated. The added information could be used to potentially guide decisions about preventive treatment, including statin therapy, the group suggested.
The findings also indicate that routine CAC scanning may offer less clinical value at the extremes of the risk spectrum. For patients at low risk, additional scanning could expose patients to radiation and added testing and costs without a clear benefit. Meanwhile, patients at high risk are generally candidates for statin therapy regardless of their CAC score, potentially limiting the scan’s ability to change management.
“The findings help us understand how best to use the available tools to estimate someone’s risk of a heart attack or stroke. That provides more precise guidance for who is most likely to benefit from using a statin to help prevent heart disease,” Shah said.
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In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.