Many research studies have focused on evaluating the predictive ability of coronary artery calcium (CAC) scoring in cohorts primarily consisting of middle-aged individuals.^1,2 The results of other recent studies have suggested that CAC may also be useful in assessing the risk of cardiovascular (CV) and all-cause mortality in older individuals.^3,4 This potential use may be particularly true for patients with diabetes mellitus (DM) who do not have other DM-specific risk-enhancing factors.⁵ However, assessing the risk of CV-related mortality in the general population of patients ≥65 years of age remains difficult because traditional CV risk factors such as high cholesterol levels lose their predictive value for adverse CV events in older patients.⁶ Assessing CV-related risk in older patients who do not exhibit any traditional CV risk factors is even more difficult. To aid in decision making, the American College of Cardiology (ACC) and American Heart Association (AHA) recommend considering CAC testing for adults between 76 and 80 years of age without DM who have low-density lipoprotein cholesterol levels between 70 and 189 mg/dL.⁷

To characterize the distribution of CAC in the general, healthy US population ≥75 years of age and to construct CAC population percentiles, 2,886 participants without clinical coronary heart disease from the ARIC (Atherosclerosis Risk in Communities) study and the MESA (Multi-Ethnic Study of Atherosclerosis) were studied.⁸ The median age of the group under study was 80 years, with an interquartile range of 77-83 years. Two percent of men and 9% of women had a CAC score of 0. Most participants (62.5%) had a CAC score of >100. The CAC scores increased with age, with almost 95% of participants ≥90 years of age having CAC across all sex/race subgroups.

According to the ACC and AHA, patients 40-75 years of age with a CAC score of ≥100 should receive statin therapy, regardless of whether they have clinical coronary disease.⁷ However, the newly published CAC percentiles for individuals ≥75 years of age show that most individuals in this population have a CAC score >100 despite having no symptoms of coronary artery disease.⁹ This finding makes it difficult to use traditional CAC score groups alone to determine their risk of CV disease; thus, a new approach is required in this age group. A CAC score of 0 can still be a good indicator of survival prognosis in this patient population.⁹ This finding emphasizes the challenge of managing subclinical atherosclerosis in this group using current paradigms.⁹ New data are needed to guide potential clinical decision making. The ongoing PREVENTABLE (Pragmatic Evaluation of Events And Benefits of Lipid-lowering in Older Adults) trial, funded by the National Institutes of Health (NIH), will assess the effectiveness and safety of high-intensity statin therapy in adults ≥75 years of age. An ancillary study (CAC PREVENTABLE) will explore the role of baseline CAC scores in predicting net clinical benefit.¹⁰

Assessing CV risk in older individuals is a complex and evolving field that requires a nuanced approach, and imaging may play a role. Although CAC scoring is a promising predictive tool, with broad guideline endorsement for the middle-aged population at borderline to intermediate risk, guidance in older individuals remains limited. The definition of "low" and "high" CAC scores for guiding treatment decisions in individuals ≥75 years of age are yet to be defined. The intricacies of managing CV health in older patients are highlighted by the PREVENTABLE trial results, and hopefully insights will be gained by the embedded, blinded CAC ancillary study. As clinicians navigate the increasingly common question of CV risk assessment in older patients, ongoing research efforts are crucial to refine clinical understanding and guide evidence-based decision making tailored to the unique characteristics of this population that considers the relative value of traditional risk factors, serum biomarker levels (e.g., high-sensitivity troponin and N-terminal pro-B-type natriuretic peptide), and imaging tests such as the CAC score. In the meantime, the CAC score should be limited to selective use in this population in the context of a patient-clinician risk discussion.

References

1. Gerke O, Lindholt JS, Abdo BH, et al. Prevalence and extent of coronary artery calcification in the middle-aged and elderly population. Eur J Prev Cardiol 2022;28:2048-55.
2. Mehta A, Pandey A, Ayers CR, et al. Predictive value of coronary artery calcium score categories for coronary events versus strokes: impact of sex and race. Circ Cardiovasc Imaging 2020;13:[ePub ahead of print].
3. Wang FM, Rozanski A, Arnson Y, et al. Cardiovascular and all-cause mortality risk by coronary artery calcium scores and percentiles among older adult males and females. Am J Med 2021;134:341-350.e1.
4. Blaha MJ, Cainzos-Achirica M, Dardari Z, et al. All-cause and cause-specific mortality in individuals with zero and minimal coronary artery calcium: a long-term, competing risk analysis in the Coronary Artery Calcium Consortium. Atherosclerosis 2020;294:72-9.
5. Obisesan OH, Orimoloye OA, Wang FM, et al. Coronary artery calcium scores in older adults with diabetes and their association with diabetes-specific risk enhancers (from the Atherosclerosis Risk in Communities Study). Am J Cardiol 2023;201:219-23.
6. Dalton JE, Rothberg MB, Dawson NV, Krieger NI, Zidar DA, Perzynski AT. Failure of traditional risk factors to adequately predict cardiovascular events in older populations. J Am Geriatr Soc 2020;68:754-61.
7. Blankstein R. 2018 Cholesterol Guideline and the Judicious Use of Coronary Calcium Score: What Does a Cardiologist Need to Know? (American College of Cardiology website). 2019. Available at: https://www.acc.org/latest-in-cardiology/articles/2019/08/20/11/06/2018-cholesterol-guideline-and-the-judicious-use-of-coronary-calcium-score. Accessed 03/01/2024.
8. Wang FM, Cainzos-Achirica M, Ballew SH, et al. Defining demographic-specific coronary artery calcium percentiles in the population aged ≥75: the ARIC study and MESA. Circ Cardiovasc Imaging 2023;16:[ePub ahead of print].
9. Tota-Maharaj R, Blaha MJ, McEvoy JW, et al. Coronary artery calcium for the prediction of mortality in young adults <45 years old and elderly adults >75 years old. Eur Heart J 2012;33:2955-62.
10. Joseph J, Pajewski NM, Dolor RJ, et al. Pragmatic evaluation of events and benefits of lipid lowering in older adults (PREVENTABLE): trial design and rationale. J Am Geriatr Soc 2023;71:1701-13.