Coronary Artery Calcium Prevalence Differs Among People Without Known ASCVD

James H. Stein, MD

Credit: University of Wisconsin

New research provided updated insights into the prevalence of incidental coronary artery calcium (CAC) in people without known atherosclerotic cardiovascular disease (ASCVD).¹

Based on detection rates from the Multi-Ethnic Study of Atherosclerosis, the analysis showed substantial differences in CAC prevalence by age, sex, race, and ethnicity, and might provide a valuable framework for patient-physician discussion on clinical decision-making.

“Although CAC presence is associated with increased ASCVD risk regardless of age, CAC is common as age increases,” wrote the investigative team, led by James H. Stein, MD, Robert Turell Professor of Cardiovascular Research, University of Wisconsin School of Medicine and Public Health. “Its detection provides an opportunity to discuss ASCVD risk but should avoid provoking unnecessary patient anxiety.”

Results from a recent investigation using a deep-learning algorithm to identify CAC on nongated chest CT showed notifying a care team of CAC increased statin prescriptions, cardiology clinic visits, and stress tests.²

Knowledge of the expected prevalence of CAC in people without ASCVD could ultimately improve clinical decision-making, and avoid unnecessary testing performed only to alleviate physician or patient anxiety. Age and sex, as well as race and ethnicity, are factors that significantly impact the prevalence of CAC.

In this analysis, Stein and colleagues aimed to frame the patient-physician discussion using CAC detection rates in the Multi-Ethnic Study of Atherosclerosis.¹ The population of the Multi-Ethnic Study of Atherosclerosis consisted of people aged 45 to 84 years who were free of clinical ASCVD at the study baseline (2000 - 2002). Investigators measured CAC using electrocardiogram-gated multidetector or electron-beam CT techniques.

Baseline data from 6814 participants were included in the report. The population had a mean age of 62 years, 53% were women, and 47% were men. Self-reported race and ethnicity showed 41% of patients were White, 26% were Black, 21% were Hispanic, and 12% were Chinese.

Upon analysis, investigators found the prevalence of a nonzero Agatston CAC score increased with age, in all combinations of sex, race, and ethnicity. The analysis showed men had a higher prevalence than women of detectable CAC across all age strata.

Results showed the age when CAC exceeded 50% varied, by sex, race, and ethnicity. The age was as young as 50 to 54 years in non-Hispanic White men, to older than 70 years in both non-White and Hispanic women.

The team added that while the detection of CAC presence is an opportunity to discuss ASCVD risk, it should not provoke unnecessary patient anxiety. According to the data, approximately 90% of White men have CT-detectable CAC at ages 70 to 74, while Black women only have a 50% CAC prevalence at the same age.

Due to the high prevalence of CAC at older ages, investigators indicated CAC on a CT scan should not immediately lead to a specialist referral or statin prescription. Instead, a comprehensive ASCVD risk assessment with consideration of competing risks and patient preferences is warranted.

The team noted the absence of CAC on CT scans not dedicated to CAC detection and scoring may not prove as useful as risk stratification on dedicated scans.

“The fundamental principle that test results can modify but cannot replace pretest disease likelihood is vital to the influence of incidental CAC detection on ASCVD risk assessment,” investigators wrote.

References

1. Tattersall MC, McClelland RL, Nagpal P, Deaño R, Blaha MJ, Stein JH. Incidental Coronary Artery Calcium on Chest CT in Persons Without Known Atherosclerotic Cardiovascular Disease. JAMA Intern Med. Published online September 25, 2023. doi:10.1001/jamainternmed.2023.3317
2. Sandhu AT, Rodriguez F, Ngo S, et al. Incidental coronary artery calcium: opportunistic screening of previous nongated chest computed tomography scans to improve statin rates (NOTIFY-1 project). Circulation. 2023;147(9):703-714. doi:10.1161/CIRCULATIONAHA.122.062746PubMed