Distribution and burden of newly detected coronary artery calcium: Results from the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: The transition from no coronary artery calcium (CAC) to detectable CAC is important, as even mild CAC is associated with increased cardiovascular events. We sought to characterize the anatomic distribution and burden of newly detectable CAC over 10-year follow-up. METHODS: We evaluated 3112 participants (mean age, 58 years; 64% female) with baseline CAC = 0 from the Multi-Ethnic Study of Atherosclerosis. Participants underwent repeat CAC testing at different time intervals (between 2-10 years after baseline) per the Multi-Ethnic Study of Atherosclerosis protocol. Among participants who developed CAC on a follow-up scan, we used logistic regression and marginal probability modeling to describe the coronary distribution and burden of new CAC by age, sex, and race after adjustment for cardiovascular risk factors and time to detection. RESULTS: A total of 1125 participants developed detectable CAC during follow-up with a mean time to detection of 6.1 ± 3 years. New CAC was most commonly isolated to 1 vessel (72% of participants), with the left anterior descending artery (44% of total) most commonly affected followed by the right coronary (12%), left circumflex (10%), and left main (6%). These patterns were similar across age, sex, and race. In multivariate models, residual predictors of multivessel CAC (28% of total) included male sex, African American or Hispanic race, hypertension, obesity, and diabetes. At the first detection of CAC >0, burden was usually low with median Agatston CAC score of 7.1 and <5% with CAC scores >100. CONCLUSION: New-onset CAC most commonly involves just 1 vessel, occurs in the left anterior descending artery, and has low CAC burden. New CAC can be detected at an early stage when aggressive preventive strategies may provide benefit.

Assessment of subclinical coronary atherosclerosis in asymptomatic patients with type 2 diabetes mellitus with single photon emission computed tomography and coronary computed tomography angiography.

We evaluated the characteristics of coronary artery disease in asymptomatic patients with type 2 diabetes mellitus (DM) using single photon emission computed tomography (SPECT) and coronary computed tomographic angiography (CCTA). A total of 116 patients with DM without abnormal electrocardiographic findings or evidence of peripheral arterial disease (number of risk factors > or =2; 62 +/- 7 years, 59% men) underwent CCTA and SPECT. Of the 116 patients with DM, 88 (76%) had a normal single photon emission computed tomographic findings, and 28 (24%) had abnormal perfusion defects. Of the 116 patients, 92 (79%) had atherosclerotic plaques (2 +/- 2 segments per subject), and 20 (17%) had significant stenosis seen on CCTA. Patients with DM and normal findings on SPECT had a similar prevalence of atherosclerotic plaque (78% vs 82%), significant stenosis (15% vs 25%), severe stenosis (7% vs 7%), and calcified (40% vs 43%), mixed (49% vs 57%), and noncalcified plaques (26% vs 29%) and a high (>100) coronary artery calcium score (32% vs 29%; all p >0.05) compared to those with abnormal findings on SPECT. During the mid-term follow-up (24 +/- 4 months), 5 cardiac events occurred in patients with DM and normal findings on SPECT, only in those with occult CAD on CCTA: 1 sudden cardiac death and 4 revascularization procedures. In conclusion, a significant percentage of patients with DM and normal eletrocardiographic findings, no peripheral arterial disease, and normal findings on SPECT have evidence of occult CAD on CCTA. Furthermore, a small percentage had had a cardiac event by mid-term follow-up. SPECT showed limited capability to differentiate the coronary risks between patients with DM and no coronary plaque and from those with a certain degree of disease; 2 circumstances that represent different coronary risks.