Abstract 3262: Impact of the MESA Arterial Age Calculator Incorporating Coronary Calcium on CHD Risk Estimation

Abstract

Background: The MESA study recently published a web-based calculator for the computation of arterial age incorporating Framingham risk factors and coronary calcium to integrate the incremental predictive value of coronary calcium within the Framingham risk score, a reference-standard clinical coronary heart disease (CHD) risk calculator. We examined the impact of arterial age on the distribution of CHD risk estimation. Methods: We applied CHD risk factor data from the Prospective Army Coronary Calcium Project, a screening cohort of 2000 men and women between the ages of 40 and 50, to the MESA Arterial Age calculator (available at www.mesa-nhlbi.org). Subjects were studied with measured CHD risk factors and electron beam CT for the identification of coronary artery calcium. Framingham risk scores (FRS), using the 10 year CHD risk model with and without arterial age, were calculated using the MESA arterial age calculator. An estimate CHD risk between 6 and 20% was categorized as intermediate risk, and compared for the calculations using chronological age, and arterial age. Results: Demographics of the cohort included mean age 42.9 ± 2.7 yrs, male gender 82%, hypertension 8.0%, systolic blood pressure 123 ± 13 mm Hg, current smoking 7.7%, total cholesterol 203 ± 36 mg/dL, and HDL-C 53 ± 14 mg/dL. Mean FRS was 4.5 ± 3.6%. Coronary calcium was present in 394 subjects (19.7%). Application of the arterial age calculator increased mean age from 42.9 ± 2.7 to 43.6 ± 10.4 years (P < .001), and the mean FRS increased from 4.5 ± 3.6 to 7.3 ± 8.1% (P < .001). Reclassification was seen primarily among male subjects, in whom the mean age (chronological vs. arterial age) increased from 42.9 ± 2.7 to 44.2 ± 11.0 (P < .001) and the prevalence of intermediate CHD risk increased from 26.2% (429 of 1639) to 37.4% (613/1639; P < .001). Among women, mean age (chronological vs. arterial age) was reduced by calcium scoring (42.7 ± 2.6 vs. 40.7 ± 6.3%; P < .001) and a shift to intermediate risk was seen in only 0.6% of subjects (from 10 to 18 out of 349). Conclusions: Among healthy middle-aged individuals, the MESA arterial age calculator modestly shifts predicted CHD risk estimation, and reclassifies 1 in 9 men from low to intermediate risk. Arterial age was lower than chronological age in women.