(CCSP123) CORONARY ARTERY CALCIUM SCORE IS ASSOCIATED WITH CAROTID PLAQUE BURDEN IN LOW-INTERMEDIATE RISK PATIENTS

Background: Carotid ultrasound identifies and quantifies atherosclerotic plaque and has been shown to be associated with coronary artery disease and events. The coronary artery calcium (CAC) score uses computed tomography (CT) to quantify calcified lesions and is associated with major adverse cardiovascular events and the Framingham Risk Score. However, the CAC score requires radiation and is more costly and time-consuming compared to ultrasound. This study investigated the association between CAC score and carotid total plaque quantity and composition.

METHODS AND RESULTS: Adult participants (n=35) with no history of cardiovascular disease and referred for stress echo were recruited to undergo B-mode ultrasound of the carotid arteries. Maximum plaque height, total plaque area, and plaque score (Rotterdam method) was measured. Ultrasound images were uploaded to a semi-automated software, Intelliplaque ™, for grayscale pixel distribution analysis to determine tissue composition within plaques. Participants underwent a cardiac CT for CAC scoring within 1-year of their carotid ultrasound. CAC scores were determined using the Agatston method. CAC scores were categorized as absent (0), mild (1-99), moderate (100-399), and severe (400+). The mean age of participants was 64 ±11 years. Total plaque area, maximum plaque height, and plaque score were significantly associated with CAC score (r=0.71, p< 0.0001; r=0.44, p=0081; and r=0.60, p=0.0002). With regards to CAC score categories, a one-way ANOVA revealed that there was a significant difference in the mean total plaque area of those in the severe CAC score category compared to those in the absent, mild, and moderate categories (Figure). Echogenic plaque composition features (% Fibrous and % Calcium) were not associated with CAC score (Table).

Conclusion: While carotid plaque burden was associated with CAC score, plaque composition was not. Plaque vulnerability is known to be associated with lipid or hemorrhagic tissue. While carotid ultrasound gives information on both burden and composition, CAC score only identifies calcification. Although these two techniques looked at different vascular beds, we found correlations in regard to atherosclerotic burden. Carotid ultrasound used in conjunction with traditional risk factors may be an alternative to CT. Carotid ultrasound is low cost and can be easily incorporated into clinic visits. Carotid ultrasound may improve the prediction of cardiovascular disease and aid in assessing the risk for future events in low to moderate risk populations.