OBJECTIVES This study aimed to investigate clinical and coronary computed tomographic angiography (CTA) characteristics of lesions that progressed to chronic total occlusion (CTO).

BACKGROUND CTO is one of the most common reasons for referral to coronary artery bypass surgery. Prediction and adequate early management for future CTO lesions may be beneficial.

METHODS The study evaluated patients with at least 1 vessel with a diameter stenosis of ≥70% on invasive coronary angiography (ICA) who underwent previous coronary CTA >12 months before ICA, from 2006 to 2015. The study compared the baseline clinical and coronary CTA characteristics of the patients with future CTO lesions with those of the patients with future non-CTO lesions (patient-level analysis) and compared coronary CTA findings between the future CTO lesion with the most stenotic non-CTO lesion in each CTO patient (lesion-level analysis).

RESULTS Among the 216 patients, 32 (14.8%) had a CTO lesion on ICA. In patient-level analysis, no significant differences in clinical characteristics were found, whereas the coronary CTA culprit lesions of the CTO group had a smaller minimal lumen diameter (MLD) with more adverse plaque characteristics. In lesion-level analysis, future CTO lesions had a smaller MLD, a smaller reference segment diameter (RD), and longer lesion length. These lesions were more likely to be noncalcified plaques with a noneccentric cross-sectional distribution, and had a higher remodeling index, lower mean plaque attenuation (MPA), and more napkin-ring signs. In multivariate analysis and receiver-operating characteristic curve analysis, MLD of <2.0 mm, RD of <3.2 mm, and MPA of <50 Hounsfield units were independent predictors of future CTO lesions. The risk of CTO development in lesions with triple risk factors was 14-fold higher than that of the lesions with no risk factors.

CONCLUSIONS Lesions that progressed to CTO had more severe baseline coronary CTA features than non-CTO lesions. A small MLD, small RD, and low MPA were independent predictors of progression to CTO.