Coronary Artery Calcium Scoring for Intermediate Cardiovascular Risk Patients
You do not need to refer a patient to a cardiologist to obtain a coronary artery calcium (CAC) score, as this test can be ordered directly by primary care physicians for appropriate patients with intermediate cardiovascular risk. 1
Patient Selection for CAC Scoring
Recommended for:
- Intermediate-risk patients (10-year ASCVD risk of 7.5% to <20%) where decision about statin therapy remains uncertain 1
- Selected borderline-risk patients (10-year ASCVD risk of 5% to <7.5%) where additional risk stratification would help guide therapy 1
- Patients aged 45-75 years without known coronary disease who are asymptomatic 2
- Patients with diabetes aged 40-60 years 2
- Patients with family history of premature cardiovascular disease where traditional risk calculators may underestimate risk 1, 3
Not recommended for:
- Low-risk patients (<5% 10-year risk) 1
- Patients already diagnosed with coronary artery disease 4
- Patients with a clear indication for statin therapy based on other risk factors 1
Clinical Decision-Making Based on CAC Score
CAC Score = 0
- Reasonable to withhold statin therapy and reassess in 5-10 years 1
- Exception: Consider statin therapy despite CAC=0 if patient has diabetes, family history of premature CHD, or is a smoker 1
- Very low event rate (annual mortality <0.5%, coronary event rate 0.4% over 3-5 years) 5
CAC Score = 1-99
- Reasonable to initiate statin therapy for patients ≥55 years of age 1
- Represents mild to moderate risk (1.2-2.2 times higher risk of cardiovascular events) 5
- Consider reassessment in 3-5 years 5
CAC Score = 100-399
- Strongly recommend statin therapy 1, 2
- Represents moderate to high risk (4.3 times higher relative risk) 5
- Consider aspirin therapy if no contraindications 2
CAC Score ≥400 or ≥75th percentile for age/sex
- Strongly recommend high-intensity statin therapy 1, 5, 2
- Represents severe to very high risk (7.2 times higher relative risk) 5
- Recommend aspirin therapy if no contraindications 2
- Consider more aggressive risk factor management 5
Clinical Impact of CAC Scoring
- Improves risk stratification beyond traditional risk calculators with net reclassification improvement of 14-30% 6
- Most valuable in intermediate-risk patients where treatment decisions are uncertain 1, 6
- Can help motivate statin-reluctant patients by demonstrating actual atherosclerotic burden 1
- May help identify patients who would benefit from more aggressive preventive therapy 1
- Provides incremental prognostic information beyond traditional risk factors 7
Practical Considerations
- CAC scoring involves minimal radiation exposure (approximately 1-1.5 mSv) 1
- Cost has decreased to <$100 at many imaging centers, making it cost-effective for risk stratification 1
- Should be performed with prospective ECG triggering to minimize radiation dose 1
- Not generally recommended for men <40 years or women <50 years due to low prevalence of detectable calcium 1
Bottom Line
CAC scoring provides valuable risk stratification for patients with intermediate cardiovascular risk and can guide decisions about preventive therapies, particularly statins. The test can be ordered directly by primary care physicians without requiring a cardiology referral, and the results provide actionable information to guide evidence-based treatment decisions.