Background and aims: Use of coronary artery calcium (CAC) continues to expand, and several different categories of risk have been developed. Some categorize CAC as <10, 11-100 and > 100, while others use CAC = 0,1-10, 11-100 and > 100 as categories. We sought to evaluate the plaque burden in patients with CAC 0, 1-10 and 11-100 to evaluate the best use of CAC scoring for risk assessment.
Methods: Patients were recruited from existing prospective CCTA trials with CAC scores ≤100 and quantitative coronary plaque analysis (QAngio, Medis). CAC was categorized into three groups: zero (CAC = 0), minimal (CAC 1-10), and mild (CAC 11-100). Plaque levels (low attenuated, fibrous, fibro-fatty, dense calcified, total non-calcified) were assessed using multivariable linear regression adjusted for cardiovascular risk factors (age, ethnicity, BMI, gender, hypertension, dyslipidemia, diabetes mellitus, past smoking).
Results: 378 subjects were included, with an average age of 53.9 ± 10.7 years and 53 % female. Among them, 51 % had 0 CAC, 16 % had minimal CAC (scores 1-10), and 33 % had mild CAC (scores 11-100). The minimal and mild CAC groups were significantly older, with higher rates of diabetes, hypertension, and hyperlipidemia. Multivariable analysis found no significant difference in low attenuated, fibro-fatty, and dense calcified plaque levels between the minimal and zero CAC groups. However, minimal CAC subjects had significantly higher fibrous, total non-calcified, and total plaque volumes than zero CAC. All plaque types were significantly higher in the mild group when comparing mild CAC to minimal CAC.
Conclusion: Individuals with minimal calcium scores (1-10) had greater noncalcified coronary plaque (NCAP) and total plaque volume than individuals with a calcium score of zero. The increased presence of NCAP and total plaque volume in the minimal CAC (1-10) is clinically significant and place those patients at higher coronary vascular disease (CVD) risk than individuals with absent CAC (CAC = zero). Therefore, the use of CAC = 0, 1-10 and 11-100 is prudent to better categorize CVD risk.
Keywords: Cardiovascular disease; Coronary artery calcium; Coronary artery disease; Risk.
Published by Elsevier Inc.