Abstract 3754: Distribution of Subclinical Aortic Atherosclerosis Detected as Abdominal Aortic Calcification in the Framingham Heart Study
Background: Abdominal aortic calcification (AAC) is a marker of aortic atherosclerosis that is an independent predictor of incident cardiovascular disease (CVD). AAC is easily detected using non-invasive computed tomography imaging. Quantitative measures of the extent of AAC may be useful for identifying individuals at increased CVD risk, but age- and sex-specific thresholds for AAC have not been developed.
Methods: Participants of the Framingham Offspring and Third Generation cohorts who attended examinations from 1998 –2005 underwent abdominal scanning using eight-slice multi-detector computed tomography (MDCT). Twenty-five 5.0-mm abdominal slices were acquired. The presence and amount of AAC between L1-L4 was determined by an experienced reader. A calcified lesion was defined as an area of at least 3 connected pixels with CT attenuation >130 HU applying 3-dimensional connectivity criteria (six points). A modified Agatston score (AS) was calculated for each participant.
Results: Overall, 1677 men (mean age 50 years) and 1608 women (mean age 53 years) underwent MDCT scanning. The distribution by age and sex of 75th, 90th and 95th percentile cut-points for AAC is shown (Table ⇓). For both men and women, relative (percentiles) and absolute values (AS) increase markedly with age. The percentile AS cutpoint for AAC is consistently higher in men compared to women across all age categories. Additionally, the 90th percentile AS for AAC is higher at every age category than for coronary artery calcification (CAC) in both men and women.
Conclusions: The extent of AAC is higher in men than women and increases with age. Further, the amount of calcification is much higher than in the coronary arteries. The use of AAC as a marker that can be measured in routine non-contrast abdominal CT for risk stratification and prediction of CVD, as well as the relation to CAC warrants further study.