CAC Percentile (MESA Reference): Explanation and Clinical Context
The Coronary Artery Calcium (CAC) Percentile, based on the Multi-Ethnic Study of Atherosclerosis (MESA) reference equations, provides an age-, sex-, and race-specific comparison of an individual’s coronary calcium burden against a large, population-based cohort. It contextualizes the raw Agatston score by expressing it as a percentile of expected CAC for a given demographic profile.
For example, a CAC percentile of 75 indicates that the individual’s coronary calcium burden is higher than 75% of peers with the same age, sex, and race. This percentile adds interpretive value to the Agatston score, allowing better cardiovascular risk stratification.
Interpretation:
- 0 percentile: No detectable coronary calcification (very low risk).
- 1–25th percentile: Below-average CAC burden for age/sex/race.
- 26–75th percentile: Intermediate risk, indicating early atherosclerotic changes.
- >75th percentile: High CAC burden; substantially increased atherosclerotic risk.
The MESA model is based on >6,800 asymptomatic adults from four ethnic groups (White, Black, Hispanic, Chinese-American) and represents the gold standard for CAC percentile assessment. Clinical integration of CAC percentile helps guide primary prevention strategies such as initiation or intensification of statin therapy, and refinement of global ASCVD risk estimates.
Reference:
McClelland RL, Chung H, Detrano R, Post W, Kronmal RA. Distribution of coronary artery calcium by race, gender, and age: Results from the Multi-Ethnic Study of Atherosclerosis (MESA). Circulation. 2006;113(1):30–37. doi:10.1161/CIRCULATIONAHA.105.580696
McClelland RL, et al. 10-Year Coronary Heart Disease Risk Prediction Using Coronary Artery Calcium and Traditional Risk Factors: The Multi-Ethnic Study of Atherosclerosis (MESA). JACC. 2015;66(15):1643–1653. doi:10.1016/j.jacc.2015.08.035