Differentiation of severe coronary artery calcification in the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND

Coronary artery calcium (CAC) scores predict coronary heart disease (CHD) risk. Little is known, however, about the distinctive risk among asymptomatic individuals with very high CAC (≥ 1000) compared to high CAC (400-999).

METHODS AND RESULTS

We compared CHD risk factors and event rates between participants with very high CAC (n = 257) and high CAC (n = 420) among adults free of clinical CHD in the Multi-Ethnic Study of Atherosclerosis (MESA). CAC was measured at baseline, and participants were followed for a median of 68 months. Very high CAC (≥ 1000), compared to high CAC (400-999), was associated with male gender (OR 3.10, p < 0.001) and older age (OR 1.42 per 10 year increase, p < 0.001). Chronic kidney disease (CKD) was associated with very high CAC (OR 1.66, p = 0.009) with a greater prevalence of moderate CKD (GFR 30-59) in the ≥ 1000 group (25% vs. 18%). Those with very high CAC were more likely to develop angina (adjusted HR 1.72 [95% CI 1.03-2.90], p = 0.04), but not more likely to experience myocardial infarction, resuscitated cardiac arrest, or CHD death (adjusted HR 1.17, [95% CI 0.64-2.12] p = 0.61) compared to high CAC. Total CHD event rates were greater for very high CAC (3.7 per 100 person-years) compared to high CAC (2.6 per 100 person-years).

CONCLUSIONS

Both high and very high CAC are associated with an elevated risk of CHD events in those without symptomatic CHD at baseline; however, very high CAC is associated with an increased risk of angina, but not CHD death or MI, compared to high CAC.