The following are key points to remember about coronary artery calcium (CAC) scoring for guiding primary prevention of atherosclerotic cardiovascular disease (ASCVD):

1. CAC testing is a rapid, cost-effective, and highly reproductible computed tomography scan of the heart; it does not require use of contrast, intravenous access, or special preparation by the patient.
2. Radiation exposure is ~1 mSv, which is about one-third to one-half of the annual background radiation exposure in the United States.
3. CAC scores should be reported as 1) total score for the patient and 2) scores for each individual coronary artery. Score percentiles for age, sex, and race/ethnicity should also be provided.
4. Absolute CAC score best predicts 5- to 10-year absolute risk and is usually the best parameter for decisions on pharmacologic therapy. CAC score percentiles best predict lifetime risk trajectory.
5. Recommendations are provided in the multisociety 2018 guideline on the management of blood cholesterol and were endorsed in the 2019 guideline on the primary prevention of cardiovascular disease.
6. These guidelines state that CAC scoring is reasonable (Class IIA) for guiding ASCVD prevention in 1) asymptomatic adults ages 40-75 years with low density lipoprotein cholesterol (LDL-C) 70-189 mg/dL and who are at intermediate risk or 2) in selected patients at borderline risk if risk-based decision for statin therapy remains uncertain. Intermediate risk means 10-year ASCVD risk of 7.5-19.9%; borderline risk means 10-year ASCVD risk of 5.0-7.4%.
7. Other patient groups may also benefit from CAC scoring to guide preventive therapy, like low-risk adults with a strong family history of premature coronary artery disease or selected patients ages 76-80.
8. CAC scoring is not recommended in the broad general population for those with estimated 10-year ASCVD risk <5%, ASCVD risk ≥20%, or with clinical ASCVD.
9. CAC score of 0 is a very strong negative risk factor for future cardiovascular events and mortality.
10. CAC score >100 is associated with a cumulative 10-year incidence of ASCVD events >7.5%, which supports initiation of statin therapy.
11. CAC score ≥300 is associated with a 10-year incidence of ASCVD >15% and suggests benefit from greater LDL-C lowering; high-intensity statin should be considered.
12. CAC score ≥1,000 suggests potential value of very aggressive LDL-C lowering and implementation of other risk-reduction strategies.
13. No evidence supports the benefit of stress testing or invasive coronary arteriography in asymptomatic persons with a high CAC score.

Clinical Topics: Dyslipidemia, Noninvasive Imaging, Prevention, Atherosclerotic Disease (CAD/PAD), Lipid Metabolism, Nonstatins, Novel Agents, Statins, Computed Tomography, Nuclear Imaging, Stable Ischemic Heart Disease

Keywords: Atherosclerosis, Coronary Artery Disease, Cardiovascular Diseases, Calcium, Primary Prevention, Risk Factors, Tomography, X-Ray Computed, Cholesterol, LDL, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Background Radiation

< Back to Listings