Eligibility of Individuals With Subclinical Coronary Artery Calcium and Intermediate Coronary Heart Disease Risk for Reclassification (from the Framingham Heart Study)

Coronary artery calcium (CAC) predicts risk for coronary heart disease (CHD) events and perhaps CAC testing may further stratify risk in individuals at intermediate CHD risk. We sought to determine the percentage of participants at intermediate CHD risk who could potentially be reclassified as having a high CHD risk based on the presence of a high CAC score and the prevalence, treatment, and control of CHD risk factors in this group. Framingham Heart Study Offspring and Third Generation cohort participants underwent multidetector computed tomography (n = 3,529, mean age 51 years, 48% women). High CAC was defined as ≥90th age- and gender-specific percentiles based on a healthy reference group or by an absolute modified Agatston score of 100 HU. Prevalence of CHD risk factors (hypertension, hypercholesterolemia, high low-density lipoprotein cholesterol, low high-density lipoprotein cholesterol, smoking, and obesity), their treatment, and control was compared between nondiabetic participants with and without high CAC. Of the 595 participants at intermediate CHD risk, 22% had CAC ≥90th percentile and 39% had CAC ≥100 and could be eligible for reclassification as having a high CHD risk based on the presence of a high CAC score. There were no statistically significant differences in prevalence, treatment, and control of risk factors between those with and without high CAC. In conclusion, prevalence of CHD risk factors did not differ between intermediate-risk participants with and without high CAC. Approximately 25% of intermediate-risk individuals have high CAC scores and may be eligible for reclassification into a higher-risk category.