Imaging-guided evaluation of subclinical atherosclerosis to enhance cardiovascular risk prediction in asymptomatic low-to-intermediate risk individuals: A systematic review

Carotid intima-media thickness (cIMT), plaque quantification and coronary artery calcium (CAC) scoring have been suggested to improve risk prediction of cardiovascular disease (CVD), particularly for asymptomatic individuals classified as low-to-intermediate risk. We aimed to compare the predictive value of cIMT, carotid plaque identification, and CAC scoring for identifying sub-clinical atherosclerosis and assessing future risk of CVD in asymptomatic, low-to-intermediate risk individuals. We conducted a comprehensive search of Ovid (Embase and Medline), Cochrane Central Register of Controlled Trials (CENTRAL) and Medline complete (EBSCO health). A total of 30 papers were selected and data were extracted. Comparisons were made according to the cIMT measurement (mean, maximum), carotid plaque evaluation (presence or area), and CAC scoring. CVD event rates, hazard ratios (HR), net reclassification index (NRI), and c-statistic of the markers were compared. There were 27 studies that reported cIMT, 24 reported carotid plaque, and 6 reported CAC scoring. Inclusion of CAC scores yielded the highest HR ranging from 1.45 (95% CI, 1.11-1.88, p = 0.006) to 3.95 (95% CI, 2.97-5.27, p < 0.001), followed by maximum cIMT (HR 1.08; 95% CI, 1.06-1.11, p < 0.001 to 2.58; 95% CI, 1.83-3.62, p < 0.001) and carotid plaque presence (HR 1.21; 95% CI, 0.5-1.2, p = 0.39 to 2.43; 95% CI, 1.7-3.47, p < 0.001). The c-statistic enhanced predictive value by a minimum increase of 0.7. Finally, the NRI ranked higher with CAC (≥11.2%), followed by carotid plaque (≥2%) and cIMT (3%). CAC scoring was superior compared to carotid plaque and cIMT measurements in asymptomatic individuals classified as being at low-to-intermediate risk.