Comparison of high-risk plaques on CCTA with fibrous cap thickness measured by OCT and plaque burden assessed by IVUS: a multimodality imaging study

Background/Introduction High-risk plaque (HRP) detected by coronary CT angiography (CCTA) may predict future adverse events. Studies showed that plaque rupture is mainly related to fibrous cap (FC) thickness, while clinical events are associated with plaque burden (PB). Purpose To evaluate the association of HRP features with FC thickness and PB using multimodality imaging. Methods Patients undergoing pre-intervention CCTA, optical coherence tomography (OCT), and intravascular ultrasound (IVUS) were included. HRP was defined as a plaque with at least 2 of the following 4 features: positive remodeling (PR), low-attenuation plaque (LAP), napkin-ring sign (NRS), and spotty calcification (SC). FC thickness was assessed by OCT and PB by IVUS. High PB and thin FC were defined using the median values. Results A total of 549 plaques from 305 patients were analyzed (46.6% ACS, 18.7% women). CCTA-defined HRP was associated with both thin FC (OR 2.03, 95% CI 1.30–3.18; P=0.021) and high PB (OR 3.59, 95% CI 2.35–5.49; P<0.001). NRS, LAP, and SC were associated with thin FC (all P<0.05), while NRS, LAP, and PR were associated with high PB (all P<0.05) (Figure, Panel A). When all three HRP features associated with thin FC were present, the predicted probability of thin FC increased to 72% (Figure, Panel B). When all three HRP features associated with PB were present, the predicted probability of high PB increased to 77% (Figure, Panel C). Conclusions NRS, LAP, and SC were associated with thin FC, whereas NRS, LAP, and PR were related to high PB. An increasing number of HRP features was associated with a progressively higher probability of thin FC and high PB. Distinguishing HRP features of thin FC or greater PB may improve prediction of plaque disruption and risk for developing acute coronary syndromes.