Risk stratifying individuals with zero, minimal, and mild coronary artery calcium for cardiovascular disease by determining coronary plaque burden

Abstract

Background and aimsUse 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. MethodsPatients 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). Results378 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. ConclusionIndividuals 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.