Coronary Artery Calcium Score CT Screening Recommendations
Coronary artery calcium (CAC) scoring is strongly recommended for cardiovascular risk assessment in asymptomatic adults at intermediate risk (10-20% 10-year risk) of cardiovascular disease. 1
Patient Selection for CAC Scoring
Recommended for:
- Asymptomatic adults at intermediate risk (10-20% 10-year risk) 1
- Individuals with borderline or intermediate risk where treatment decisions remain uncertain 1
- Low to intermediate risk (6-10% 10-year risk) individuals 1
- Patients with risk-enhancing factors such as:
- Family history of premature coronary heart disease
- Persistently elevated triglycerides (≥175 mg/dL)
- High-sensitivity C-reactive protein ≥2.0 mg/L
- Lipoprotein(a) >50 mg/dL or >125 nmol/L
- South Asian ethnicity 1
Not Recommended for:
- Low-risk individuals (<6% 10-year risk) 1
- Men under 40 years and women under 50 years due to low prevalence of detectable calcium 1
- High-risk individuals who already qualify for intensive preventive therapy 1
Risk Stratification Based on CAC Score
CAC scores provide powerful risk stratification and help guide treatment decisions:
| CAC Score | Risk Category | Recommendation |
|---|---|---|
| 0 | Low risk | Consider withholding statin (unless diabetes, family history of premature CHD, or smoking present) [1,2] |
| 1-99 | Mild to moderate risk | Favors statin therapy (especially after age 55) [1,2] |
| 100-399 | Moderate to high risk | Initiate statin therapy [1,2] |
| ≥400 | Severe to very high risk | Initiate high-intensity statin therapy [2] |
Follow-up Recommendations
Repeat CAC scoring intervals based on initial score:
- CAC = 0: Repeat in 5-7 years
- CAC = 1-99: Repeat in 3-5 years
- CAC ≥100 or diabetes: Repeat in 3 years 2
Clinical Implications
- A CAC score of zero indicates extremely low likelihood of cardiovascular events in the next 5 years (annual mortality rate <0.5%, coronary event rate 0.4% over 3-5 years) 2
- CAC >0 is associated with significantly increased risk of major adverse cardiovascular events compared to CAC=0, with a pooled relative risk of 4.05 in asymptomatic patients 2
- The presence of CAC is a definitive marker of atherosclerotic disease and correlates with total coronary plaque burden 2
Treatment Considerations Based on CAC Score
- CAC = 0: Low risk, consider deferring statin therapy
- CAC = 1-99: Consider moderate-intensity statin therapy
- CAC = 100-399: Initiate moderate to high-intensity statin therapy
- CAC ≥400: Initiate high-intensity statin therapy with goal of LDL-C reduction ≥50% 1, 2
Important Considerations
- CAC scoring provides incremental value over traditional risk factors for predicting cardiovascular events 3
- The radiation dose for CAC scoring is relatively low (typical effective dose of 1.5 mSv) 1
- CAC scoring is cost-effective across a broad range of baseline risk 4
- No patients with a calcium score of 0 had cardiac events during follow-up in intermediate-risk populations 3
CAC scoring represents a valuable tool for refining risk assessment and guiding preventive therapy decisions in asymptomatic individuals at intermediate risk of cardiovascular disease, with strong evidence supporting its use in this population.