BACKGROUND: Previous intracoronary imaging studies have shown that coronary artery calcium (CAC) is an independent risk factor of stent underexpansion
however, limited preintervention assessments of CAC have been performed using noninvasive methods. We aimed to determine the association between lesion-specific CAC score and stent underexpansion. METHODS: In this retrospective observational study, we included 416 lesions from 359 patients who underwent intravascular ultrasound (IVUS)-guided stent implantation. CAC of each lesion was quantified using the Agatston method derived from either nongated noncontrast chest CT (NCCT) or electrocardiogram-gated coronary CT angiography (CCTA). The primary endpoint was stent underexpansion defined as minimum stent area of <
80% of the average reference lumen area. RESULTS: Overall, stent underexpansion occurred in 144 (34.6%) of 416 lesions. Lesion-specific CAC score was significantly negatively correlated with the stent expansion rate (in NCCT cohort, CONCLUSIONS: In this study, we found that lesion-specific CAC scores in both NCCT and CCTA cohorts were significantly independently associated with an increased risk of stent underexpansion, and the cutoff value to predict stent underexpansion was >
200.