Cardiology
Aiya Almogaber, PharmD
As coronary artery calcium (CAC) testing becomes more accessible, questions around its clinical utility are becoming more nuanced. A special communication published March 5, 2025, in JAMA Cardiology explores how timing—whether too early, too late, or too frequent—can influence the value and consequences of CAC testing in cardiovascular risk assessment.
“We see many patients with CAC scores that are performed inappropriately with risk of providing bad information—information that doesn’t really inform clinical care in a meaningful manner,” said Alexander R. Zheutlin, MD, from Northwestern University’s Feinberg School of Medicine and lead author of the article.
When early testing yields limited insight
CAC testing measures calcified plaque in the coronary arteries and has been recognized as a useful tool to reclassify cardiovascular risk in adults with uncertain statin eligibility. But in younger patients, especially those under 40 years without significant risk factors, the benefit may be low.
Drawing on data from major cohorts such as the Multi-Ethnic Study of Atherosclerosis and CARDIA, the authors noted that few individuals in their 30s and early 40s have detectable CAC. Among participants aged 32 to 46 years in the CARDIA study, only 1 in 10 had a CAC score greater than 0. As a result, a zero score in this population may provide false reassurance, especially for patients with risk factors such as diabetes or familial hypercholesterolemia.
Zheutlin said that CAC should be used to inform therapy decisions, not as a blanket screening tool. Premature CAC testing may delay necessary statin therapy or mislead both patients and providers into thinking a person is at low risk when long-term data say otherwise. In short, a CAC score of 0 in a young, high-risk adult should not preclude intervention.
When testing may no longer influence care
Conversely, CAC testing may not be helpful once key decisions have already been made. For example, in patients already on statin therapy, a CAC score is unlikely to influence management. Statins themselves increase calcification over time because of plaque stabilization, not disease progression, which is a finding supported by multiple studies including the PARADIGM study. Repeating CAC scores in these patients may mislead both clinicians and patients, potentially causing unwarranted concern or overtreatment.
Zheutlin noted that despite the good intentions of risk stratification, it is not uncommon to see asymptomatic individuals with high CAC scores undergo revascularization, even when they have no symptoms and maintain active lifestyles. These downstream consequences underscore the need for caution.
“The use should inform statin therapy or not,” Zheutlin said. “Careful consideration and planning based on the data is important for all clinicians to be aware of.”
When testing is done too often
Repeat testing also warrants caution, according to the study. Anecdotal reports and observational data suggest that CAC testing is sometimes repeated annually, even in patients already treated, raising questions about its utility in driving better outcomes.
While initial CAC testing can help guide decisions in select populations, repeated testing may not provide new information unless a specific change in risk status or therapy is under consideration. For example, in patients with a CAC score greater than 100 who are already on risk-evaluation therapy, repeating the test may not alter care and can instead trigger downstream testing and increase cost.
Guidelines suggest waiting at least 3 to 5 years between scans for individuals with a CAC score of zero and no major risk factors.
A tool best used selectively
Zheutlin and coauthors emphasized that the goal of their communication is to offer practical guidance, not new evidence, on when CAC testing is most useful in real-world practice.
“We hope that this message resonates with clinicians who use CAC scans in their routine practice and provides support for when, and when not, to use the test,” Zheutlin said.
Ultimately, CAC testing is most valuable in the intermediate-risk zone, such as in adults aged 40 to 75 years without diabetes or LDL levels greater or equal to 90 mg/dL when a statin decision is uncertain. In this context, a CAC score can refine risk estimates and strengthen the patient−provider discussion around preventive therapy.
However, without considering when CAC testing is too early to reflect risk, too late to change care, or too often to be useful, an opportunity is missed to apply this tool with precision. As the authors point out, its value lies not in the scan, but in how it informs safe and effective decisions. ■