Abstract 18434: Coronary Artery Calcium Progression and Atrial Fibrillation: The Multi-ethnic Study of Atherosclerosis (MESA)

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Introduction: Coronary artery calcium (CAC) measured at a single time point has been associated with an increased risk for atrial fibrillation (AF). It is currently unknown whether CAC progression over time carries a similar risk. Methods: A total of 5,612 study participants (mean age 62 ± 10; 52% women; 39% whites; 27% blacks; 20% Hispanics; 12% Chinese-Americans) from the Multi-Ethnic Study of Atherosclerosis (MESA) were included in this analysis. Phantom-adjusted Agatston scores for baseline and follow-up measurements were used to compute the change in CAC per year (1 to 100, 101 to 300, and >300 units/year) compared with participants with ≤0 change. The mean time between CT scan for study participants was 2.4 ± 0.84 years. AF was ascertained by review of hospital discharge records and from Medicare claims data through December 31, 2010. Cox regression was used to compute hazard ratios (HR) and 95% confidence intervals (95%CI) for the association between CAC progression and AF and models were adjusted for socio-demographics, cardiovascular risk factors, and baseline CAC. Results: At baseline, 2,904 (52%) participants had no evidence of CAC and 2,708 (48%) had CAC values >0. The mean CAC progression for those with baseline CAC was 46.1 ± 85.2 units per year and for those without baseline CAC was 0.84 ± 4.8 units per year. Over a median follow-up of 5.6 years, a total of 203 (3.6%) incident AF cases occurred. Any CAC progression (>0/year) was associated with an increased risk for AF (HR=1.55, 95%CI=1.10, 2.19) and the risk increased with higher levels of CAC progression per year (≤0/year: HR=1.0 [reference]; 1 to 100/year: HR=1.47, 95%CI=1.03, 2.09; 101 to 300/year: HR=1.92, 95%CI=1.15, 3.20; >300/year: HR=3.23, 95%CI=1.48, 7.05). An interaction was observed by age with the association of CAC progression with AF being stronger for younger (<61 years: HR=3.53, 95%CI=1.29, 9.69) compared with older (≥61 years: HR=1.42, 95%CI=0.99, 2.04) participants (p-interaction=0.037). Conclusion: CAC progression during an average of 5-6 years of follow-up is associated with an increased risk for AF. The associated risk is greater in individuals with faster CAC progression.