Abstract 15654: Layered Plaques and Plaque Vulnerability in Patients With Stable Angina Pectoris

Backgrounds: Layered plaque, a signature of previous plaque destabilization and healing, is one of the predictors for rapid plaque progression, the mechanism of which is unknown.

Aims: To investigate the level of vascular inflammation and plaque vulnerability in layered plaques to elucidate possible mechanisms of rapid plaque progression.

Methods: Patients who underwent both coronary computed tomography angiography (CTA) and optical coherence tomography (OCT) were selected. Plaques were defined as any tissue (noncalcified, calcified, or mixed) within or adjacent to the lumen. Pericoronary adipose tissue (PCAT) attenuation was measured at the plaque level on CTA. OCT features of plaque vulnerability were assessed at the corresponding site.

Results: A total of 475 plaques from 195 patients presented with stable angina pectoris were included. Layered plaques (n=241), compared to non-layered plaques (n=234), had a higher level of vascular inflammation (-70.94 [-77.86, -64.66] HU vs. -73.52 [-80.83, -67.66] HU, P=0.014, Figure 1). Layered plaques also had a higher prevalence of the features of plaque vulnerability (Figure 2), including lipid-rich plaque (83.8% vs. 66.7%, P<0.001), thin-cap fibroatheroma (TCFA) (26.1% vs. 17.5%, P=0.026), microchannel (61.8% vs. 34.6%, P<0.001), and cholesterol crystal (38.6% vs. 25.6%, P=0.003).

Conclusions: Layered plaque was associated with higher levels of vascular inflammation and plaque vulnerability, which might play an important role in plaque progression.