Lahti SJ, et al. - Researchers examined 28,147 asymptomatic patients with non-zero coronary artery calcium (CAC) scores in the CAC Consortium to determine if excess mortality in asymptomatic adults was predicted by left main (LM) CAC using multivariate regression, following adjustment for clinical risk factors and the Agatston CAC score. Also, they assessed the per-unit hazard related to LM CAC vs CAC in other arteries. Participants had a mean age of 58.3 ± 10 years and CAC score of 301 ± 631. Among the overall study sample, 21.7% of the cases had LM CAC present. A total of 1,907 deaths were documented during 312,398 patient-years of follow-up. Findings revealed an independent association of the presence and high burden of left main CAC with a 20–30% greater hazard for cardiovascular and total mortality in asymptomatic adults; LM CAC should be routinely observed in CAC score reports when present.