Association of Coronary Events with Burden and Distribution of Coronary Artery Calcification: Results from the Multi-Ethnic Study of Atherosclerosis

Abstract

<h3>Lead Author's Financial Disclosures</h3> Nothing to disclose. <h3>Study Funding</h3> None. <h3>Background/Synopsis</h3> Coronary artery calcium (CAC), even when mild, is associated with increased risk for coronary heart disease (CHD) events. <h3>Objective/Purpose</h3> We sought to characterize the association between number of vessels with CAC and specific artery involvement with incident CHD. <h3>Methods</h3> We evaluated participants with baseline CAC >0, free of cardiovascular disease (CVD), and follow-up from the Multi-Ethnic Study of Atherosclerosis (MESA) Exam 1 visit until adjudicated CHD, death, or censoring date of December 31st, 2018. We used Cox proportional hazard regression analyses to characterize incident CHD by number of vessels with CAC and specific artery involvement with sequential multivariable models adjusting for ASCVD risk score, body mass index, and log-transformed total calcification volume. <h3>Results</h3> There were 3,290 participants (mean age, 66 years; 42% female) with baseline CAC >0. Among these, 33% had CAC >0 in only 1 artery, 25% in 2 arteries, 30% in 3 arteries, and 12% in all 4 coronary arteries. Of those with single-vessel involvement, CAC was most frequently in the left anterior descending artery (LAD) (75%), followed by the right coronary artery (RCA) (12%), left circumflex (LCx) (10%), and left main (LM) (3%). Over follow-up of 18.5 years, 589 participants (18%) developed CHD with a mean time to event of 12.6 years. In the multivariable- adjusted Cox model, CHD risk was 1.7x higher for 3- vs 1- (95% CI 1.2-2.3, p=0.002) and 1.6x higher for 3- vs 2-vessel involvement (95% CI 1.2-2.0, p=0.0004), though similar for 1- vs 2- (p=0.7) and 3- vs 4 (p=0.8) [Figure]. Single-vessel CAC in the LAD conferred a similar risk for CHD when compared to single-vessel CAC in the LM (p=0.66), LCx (p=0.83), and RCA (p=0.31). <h3>Conclusions</h3> Subclinical coronary artery disease was most commonly in 1, 2, and 3 number of arteries, and most frequently included the LAD. Compared with having CAC in only 1 to 2 arteries, those with CAC in 3 to 4 arteries had a 60-70% higher risk of incident CHD. In the context of the multivariable-adjusted model accounting for total CAC volume, no specific artery conferred a higher CHD risk than others. Number of vessels with CAC but not specific artery distribution were important characteristics for individualized risk stratification.