Study finds heart calcium scans mainly help patients at borderline risk
A new 10-year study of over 6,000 adults found coronary artery calcium scans add little predictive value overall beyond the PREVENT risk calculator, but offer meaningful clarity specifically for patients at borderline or intermediate cardiovascular risk.
Coronary artery calcium scans have grown more popular as a tool for gauging a person's future risk of heart disease. The quick, relatively affordable CT scan detects calcium buildup in the arteries feeding the heart. But new research from Northwestern Medicine suggests the test may truly benefit a smaller group of patients than commonly assumed.
Tracking outcomes over a decade
Researchers followed more than 6,000 adults aged 45 to 79 who took part in a large multi-ethnic atherosclerosis study. At the start, each participant received both a calcium score and a risk estimate from PREVENT, the American Heart Association's cardiovascular risk calculator. Over the following ten years, 6% of participants had a heart attack or stroke.
When predictions combining calcium scores were compared with those based on PREVENT alone across the whole group, the improvement was modest — the model's ability to distinguish future events rose only from 0.73 to 0.75. The picture changed when researchers isolated participants whose PREVENT scores initially placed them in a borderline or intermediate category, meaning a 3% to 9% estimated ten-year risk. For this specific group, adding the calcium score meaningfully improved the accuracy of predicting who would actually experience a cardiovascular event.
Weighing unnecessary testing
Study senior author Dr. Nilay Shah said not everyone needs or would benefit from the scan. Using it in low-risk individuals may cause unnecessary radiation exposure and cost without clear clinical benefit, he said, while high-risk individuals are typically advised to start statins regardless of their calcium score, making the scan redundant for them too.
About 10% of U.S. adults aged 30 to 79 have cardiovascular disease, still the country's leading cause of death, though many such events are preventable. The researchers noted further studies are needed to assess the scan's value in higher-risk populations and among younger people. The study was published August 26 in JAMA.
