What is a Coronary Artery Calcium (CAC) score test?

From the Guidelines

I strongly recommend a calcium score test for adults with intermediate predicted risk (≥7.5% to <20%) of cardiovascular disease, as it can be a useful tool in refining risk assessment for preventive interventions, such as statin therapy, and can help guide shared decision-making about treatment options 1.

Key Points to Consider

• The test is a non-invasive CT scan that measures the amount of calcium buildup in the walls of the coronary arteries.
• The results are given as a score: 0 (no calcium detected), 1-100 (mild buildup), 101-400 (moderate buildup), or over 400 (severe buildup).
• Higher scores indicate greater risk of future heart attacks, and the test can help identify plaque buildup before it causes symptoms or blockages.
• The test is particularly useful for adults aged 40-75 with risk factors like high blood pressure, high cholesterol, diabetes, smoking history, or family history of heart disease.
• The calcium score can help personalize heart disease prevention by identifying individuals who may benefit from lifestyle changes, medications, or further cardiac testing.

Benefits of the Test

• Can help refine risk assessment for preventive interventions, such as statin therapy 1.
• Can help guide shared decision-making about treatment options 1.
• Can identify plaque buildup before it causes symptoms or blockages.
• Can help personalize heart disease prevention.

Recent Evidence

• A 2021 study published in the Journal of Internal Medicine found that coronary artery calcium scoring is a valuable tool for primary care physicians in assessing cardiovascular risk 1.
• A 2021 study published in the Journal of the American College of Radiology found that CT coronary calcium scoring is a useful tool for risk stratification in asymptomatic patients at risk for coronary artery disease 1.

Important Considerations

• The test is not intended as a “screening” test for all, but rather as a decision aid in select adults to facilitate the clinician–patient risk discussion 1.
• The absence of coronary artery calcium does not rule out noncalcified plaque, and clinical judgment about risk should prevail 1.

From the Research

Calcium Score Test Overview

• The coronary artery calcium score (CACS) is a measure used to assess the risk of coronary artery disease (CAD) and cardiac events 2.
• CACS is less invasive and less expensive than contrast-enhanced coronary computed tomography (CT) angiography 2.
• The test is used to quantify the amount of calcium in the coronary arteries, which is a marker of atherosclerotic plaque burden 3.

Clinical Application and Interpretation

• The CACS cutoff value of 400 has been used in many previous studies to detect significant CAD or cardiac event risk, but other studies have reported that the frequency of significant ischemia, likelihood of CAD, and cardiac event rate increase with mild to moderate CACS 2.
• A CACS of 0 is known to decrease the likelihood of CAD after assessment of pretest probability, and management using statin therapy may benefit from a CACS of 0 2.
• The combination of CACS and noninvasive cardiac imaging is significant, and CACS assessment is recommended for use in combination with risk assessment of pretest probability using clinical information including age, sex, and chest symptoms 2, 3.

Guidelines and Recommendations

• The 2018 ACC/AHA Cholesterol Guidelines endorsed the use of CAC scores in asymptomatic, intermediate-risk individuals where the decision to initiate statin therapy is uncertain 3.
• The Society of Cardiovascular CT and Society of Thoracic Radiology guidelines determined CACS ≥300 as moderate to severely increased risk in 2016 2.
• The 2019 AHA/ACC primary prevention guidelines recommend consideration of CAC scoring for further risk assessment in borderline to intermediate-risk individuals in whom management is uncertain 4.

Patient Subpopulations and Risk Estimation

• CAC scoring can be used to inform individualized ASCVD risk management in important patient subgroups, including those with high-risk race/ethnicity, chronic kidney disease, and a family history of premature ASCVD 4.
• The combination of risk-enhancing factors and CAC burden may lead to more accurate ASCVD risk assessment, but further research is needed to examine the interplay between risk-enhancing factors and CAC scoring for personalized risk estimation 4.
• CAC assessment seems a highly valuable option to inform individualized ASCVD risk management in these important, often highly heterogeneous patient subgroups 4.