Abstract 3490: Formal Comparison between absolute and relative cut points for Coronary Artery Calcification in At Intermediate Risk Community-Based Men and Women: The Framingham Heart Study
Background: Coronary artery calcification (CAC) may improve risk stratification of individuals at intermediate Framingham Risk. We determined the agreement between absolute and relative cut points to identify subjects with elevated CAC in individuals at intermediate Framingham Risk.
Methods: The amount of CAC was quantified in 3238 participants from the Framingham Heart Study (FHS) Offspring and Third Generation cohorts (48% women, mean age 53 years) free of cardiovascular disease who underwent ECG triggered cardiac MDCT. We included subjects at intermediate Framingham risk, defined as 6 –20% ten year event risk, (n = 1177) and subjects free of cardiovascular risk factors (n = 1586). Distribution of CAC according to absolute (Agatston Score [AS] > 400) and relative (90th percentile stratified by age as derived from the healthy reference subset) cut-points were determined for men and women
Results: Among men with intermediate FRS, 17.7% had CAC above the 90th percentile of the healthy referent sample, whereas 14% had CAC > 400. Similar findings were observed in women: 11.5% had CAC above the 90th percentile of the healthy referent sample, whereas 2% had CAC > 400. Among all individuals at intermediate FRS Only 10.8% of subjects above the 90th percentile had an AS < 400.
Conclusions: The fraction of subjects with elevated CAC as determined by an AS > 400 is lower than subjects above the 90th percentile especially among women at intermediate FRS in the community-based FHS. Overall, the agreement between absolute and relative cut points to identify subjects with elevated CAC is poor in this population. Prospective outcomes studies are necessary to test the hypothesis that relative rather than absolute cutpoints of CAC should be used to further stratify subjects at intermediate risk.