From the Guidelines
A calcium artery score (coronary artery calcium or CAC score) should be ordered for intermediate-risk patients, specifically those with a 10-year atherosclerotic cardiovascular disease (ASCVD) risk of 5-20%, to help guide preventive cardiovascular care decisions. This is based on the most recent and highest quality study, which suggests that CAC measurement can be a useful tool in refining risk assessment for preventive interventions, such as statin therapy 1. The test is particularly valuable when there's uncertainty about whether to start statin therapy.
Key Considerations
- A score of zero indicates very low cardiovascular risk and might justify delaying statin therapy, while scores above zero (especially >100) suggest higher risk and support initiating or intensifying preventive measures.
- The test should not be ordered for low-risk patients (10-year risk <5%) or high-risk patients who already have clear indications for intensive preventive therapy.
- The calcium score provides direct visualization of coronary atherosclerosis, offering a personalized risk assessment beyond traditional risk factors.
- The test involves minimal radiation exposure and doesn't require contrast, making it relatively safe and straightforward for most patients.
Patient Selection
- Asymptomatic adults aged 40-75 without established cardiovascular disease, diabetes, or LDL cholesterol >190 mg/dL are the primary candidates for CAC scoring.
- The test may also be considered for selected low-risk adults with a strong family history of premature coronary heart disease (CHD) or other risk factors.
Clinical Decision-Making
- A CAC score of zero lowers risk and may justify withholding statin therapy, unless other risk factors are present, such as diabetes, family history of premature CHD, or cigarette smoking 1.
- A CAC score of 1-99 favors statin therapy, especially after age 55.
- A CAC score of 100+ and/or ≥75th percentile requires initiation of statin therapy.
From the Research
Indications for Calcium Artery Score
The following are indications for ordering a calcium artery score:
- Individuals with intermediate 10-year atherosclerotic cardiovascular disease (ASCVD) risk 2
- Selective populations with borderline ASCVD risk 2
- Asymptomatic patients for planning primary prevention interventions such as statins and aspirin 3
- Patients with severe hypercholesterolemia to clarify atherosclerotic cardiovascular disease (ASCVD) risk 4
- For further risk assessment and personalized management in the primary prevention of atherosclerotic cardiovascular disease 5
Patient Characteristics
The decision to order a calcium artery score should be based on individual patient characteristics, including:
- Age 6, 4
- Gender 6, 4
- Smoking status 4
- Diabetes status 4
- Systolic blood pressure 4
- Obesity 4
- Low-density lipoprotein cholesterol (LDL-C) levels 4
Interpretation of Calcium Artery Score
The interpretation of the calcium artery score is as follows:
- A score of 0 is the strongest negative predictive factor for cardiovascular disease (CVD) and can be used to de-risk a patient 2, 5
- Higher scores correlate with worse cardiovascular prognostic outcomes 2
- A score of 0 can successfully de-risk a patient and may be used to inform the safe delay or avoidance of certain preventive therapies 5