Abstract Body (Do not enter title and authors here): Background: Aortic valve calcium (AVC) is strongly associated with an increased risk for severe aortic stenosis (AS). The prevalence of AVC increases with age affecting 40-50% of individuals ≥80 years. The impact of age on the progression of AVC and its association with incident AS remains unknown.

Methods: Our study included 6,810 participants (52.9% women) free of cardiovascular disease between ages 45 and 84 from the Multi-Ethnic Study of Atherosclerosis. AVC was measured using non-contrast cardiac CT at Visit 1. Progression was calculated as the change in AVC divided by years between CT scans with up to 10 years between scans. Long term incident AS was adjudicated using medical chart review and echocardiogram data from Visit 6 with a median follow up of 16 years. Multivariable adjusted 1) linear regression was used to examine AVC progression and 2) multivariable adjusted Cox proportional hazards ratios (HR) were used to examine the association of AVC with incident AS.

Results: The prevalence of AVC >0 was 4.9% among participants <65 and 23.2% for those ≥65 years old. Among participants with AVC >0, the median AVC was 34.1 (IQR 13-1,113) for participants <65 versus 69.0 (IQR 23-2,453) for participants ≥65. Participants <65 years and ≥65 years had no significant difference in median annualized AVC progression within the baseline AVC categories of 1-99 (10 versus 12 AU/year, p=0.303) and AVC >100 (50 versus 47 AU/year, p=0.846) (Figure 1). Overall, linear regression models showed older age was associated with greater AVC progression (p=0.001), but after additional adjustment for baseline AVC, the association became non-significant (p=0.134). AVC >0 was associated with significantly increased risk of incident AS for both younger (HR 13.37; 95% CI 5.67-31.52) and older participants (HR 10.59, 95% CI 6.77-16.56).

Conclusion: We observed a similar progression of AVC for younger versus older persons after adjusting for baseline AVC burden. Additionally, AVC >0 independently conferred at least a ten-fold higher risk for severe AS among both younger and older participants. These findings demonstrate that the AVC progression is primarily associated with baseline AVC burden and that AVC is a strong marker of risk for severe AS for both younger and older persons.