Coronary calcium progression rates with a zero initial score by electron beam tomography

BackgroundA review of existing literature shows that for individuals with initial coronary calcium scores (CCS) of zero it would be reasonable to consider follow-up scanning no sooner than 3 years from the initial evaluation, however the data is very limited. In this study, we sought to determine the rate of new calcifications in patients initially presenting with a zero initial score on electron beam tomography (EBT).Methods and resultsWe evaluated 710 physician-referred participants (253 women and 448 men, mean age = 56 ± 9 years [range = 29 to 93]) with no coronary artery calcium (CAC) at baseline electron beam tomography (EBT) scan. The participants underwent a follow-up scan at least 12 months apart. In our study, 248 (35%) were followed for 1–3 years, 256 (36%) for 3–5 years and 204 (29%) for > 5 years, respectively. Overall, more than half of the individuals (62%) did not develop any CAC (score remained zero) in the interim period, whereas only 2% had CAC progression > 50 during the follow-up. The overall median (interquartile range) and mean ± S.D. change/year in these individuals was 0 (0–0.8) and 1 ± 3, respectively. Only 11 (2%) had CAC progression/year of 11–50, whereas 3 (1%) had CAC change/year > 50. It is interesting to note that even among individuals with long-term follow-up (> 5 years), very few individuals (2%) had CAC progression > 50. Individuals with follow-up 3–5 years did not have a significantly higher odds ratio for CAC change > 10 (p = 0.17) as compared to the reference group (follow-up of 1–3 years). All the other individuals who had a longer follow-up (> 5 years) had a significantly higher likelihood of CAC progression > 10 (OR = 6.6, 95% CI = 2.6–16.9, p < 0.0001) compared to the reference group.ConclusionIn individuals with no detectable coronary calcium on an initial EBT scan, a repeat scan can be recommended no sooner than 5 years.