Optical Coherence Tomography (OCT) Findings of Coronary Computed Tomography Angiography (CTA) Detected Vulnerable Plaque

Background: Recently, coronary computed tomography angiography (CTA) findings of positive vessel remodeling (PR) and low-attenuation plaque (LAP) have been reported to be associated with the development of acute coronary syndromes (ACS). The aim of this study was to examine the CTA detected vulnerable plaque characteristics by using intracoronary optical coherence tomography (OCT). Method and Result: A total of 16 patients with 16 lesions underwent PCI by using intracoronary OCT, after coronary CTA examination, were enrolled in this study. The CTA detected vulnerable plaque (CT-VP) was defined as LAP (<30 hounsfield unit (HU)) with PR of at least 110%. The lesions were divided into a CT-VP and a non CT-VP group. The CT-VP was observed in 7 lesions (43.7%) of all 16 lesions. Acute coronary syndrome (ACS) was more frequent in the CT-VP group than in the non CT-VP group (71.4% vs 11.1%, p<0.001). OCT examination revealed that the frequency of lipid-rich plaque (100% vs 33.3%, p<0.001), thin-cap fibroatheroma (TCFA) (71.4% vs 22.2%, p<0.01), plaque rupture (42.8% vs 11.1%, p<0.05), thrombus (57.1% vs 11.1%, p<0.01) and macrophage accumulation (100% vs 44.4%, p<0.01) were significantly higher in the CT-VP compared with the non CT-VP group. Conclusion: Our OCT study revealed that the CT-VP was correlated with OCT detected lipid-rich plaque, TCFA and macrophage accumulation leading plaque rupture and thrombus formation, which might contribute to the development of ACS.