Coronary Calcium Risk Calculator (MESA Model)

How Coronary Artery Calcium Modifies Cardiovascular Risk

The coronary artery calcium (CAC) score quantifies calcified atherosclerotic plaque in the coronary arteries using non-contrast cardiac CT. CAC is one of the strongest imaging predictors of future coronary events, with a clear graded relationship between calcium burden and cardiovascular risk.

The MESA CAC risk calculator combines the CAC score with traditional cardiovascular risk factors to estimate an individual's 10-year risk of coronary heart disease (CHD).

In the Multi-Ethnic Study of Atherosclerosis (MESA), CAC significantly improved risk prediction beyond traditional risk factors. Among individuals at intermediate risk, CAC testing improved risk classification by approximately 25%, allowing many patients to be reclassified into higher- or lower-risk groups.

The 2026 ACC/AHA Guideline on the Management of Dyslipidemia reinforces the role of CAC scoring in guiding lipid-lowering therapy and cardiovascular risk assessment.

2026 CAC-Based Treatment Recommendations

The 2026 ACC/AHA guideline provides treatment guidance based on CAC score in adults without established ASCVD:

• CAC = 0: Reasonable to defer statin therapy and reassess with repeat CAC in 3–7 years, provided no higher-risk conditions are present (such as familial hypercholesterolaemia, diabetes, smoking, or strong family history of premature ASCVD).
• CAC 1–99 and <75th percentile: Moderate-intensity statin therapy is reasonable, typically targeting ≥30–49% LDL-C reduction.
• CAC ≥100 or ≥75th percentile: Statin therapy is recommended. Treatment typically aims for LDL-C <70 mg/dL (1.8 mmol/L) and non–HDL-C <100 mg/dL (2.6 mmol/L).
• CAC ≥300: Indicates high atherosclerotic burden. Aggressive lipid-lowering therapy is recommended, often targeting ≥50% LDL-C reduction, with consideration of additional lipid-lowering agents if needed.
• CAC ≥1000: Represents very high atherosclerotic burden. Event rates in this group approach those seen in secondary prevention populations, and intensive lipid-lowering therapy is usually warranted.

When CAC Scoring Is Helpful

The 2026 guideline supports CAC scoring as part of a stepwise approach to cardiovascular risk assessment:

• Calculate risk using the PREVENT equations
• Personalise risk using risk-enhancing factors
• Reclassify risk with selective CAC scoring when uncertainty remains

CAC testing is particularly helpful in:

• Adults at intermediate (5–<10%) or selected borderline (3–<5%) PREVENT risk where statin decisions are uncertain
• Individuals requesting more precise risk assessment before long-term medication
• Younger adults with strong family history of premature cardiovascular disease
• Patients with elevated lipoprotein(a) or other risk-enhancing factors
• Situations where there is uncertainty about the need or intensity of lipid-lowering therapy

Incidental CAC detected on non-cardiac CT scans should also be considered when assessing cardiovascular risk.

Situations Where CAC Scoring Is Less Helpful

CAC scoring is generally not recommended or less informative in the following situations:

• Patients with established cardiovascular disease, where treatment decisions are already clear
• Patients with familial hypercholesterolaemia, where CAC = 0 should not be used to defer statin therapy
• Individuals already receiving statin therapy, since statins may increase measured CAC while stabilising plaque and improving outcomes
• Very young adults (<40 years), where non-calcified plaque may be present despite a CAC score of zero

For further information on CAC scoring indications, see our detailed guide to coronary artery calcium scoring.

Interpreting CAC Scores

The 2026 ACC/AHA guideline categorises CAC scores as follows:

• CAC = 0 → No detectable coronary calcium; very low short-term risk
• CAC 1–9 → Minimal plaque
• CAC 10–99 → Mild plaque burden
• CAC 100–299 → Moderate atherosclerosis
• CAC 300–999 → Severe atherosclerosis; event rates approach those of treated ASCVD patients
• CAC ≥1000 → Extensive atherosclerosis; event rates approach secondary prevention populations

Risk should always be interpreted in the clinical context, including age and sex percentile, symptoms, other cardiovascular risk factors, and family history.