Prevalence and culprit lesion plaque characteristics on optical coherence tomography in patients with non-st-segment elevation acute coronary syndrome with zero coronary calcification on coronary CTA

Abstract

Abstract Background CAC evaluated by non-contrast computed tomography is a marker of atherosclerosis. However, the characteristic features of CCTA and optical coherence tomography (OCT) of culprit lesions in patients with NSTE-ACS showing zero CAC remain unknown. Objectives This study aimed to assess the prevalence and characteristic features of culprit lesions on coronary CT angiography (CCTA) and optical coherence tomography (OCT) in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) showing zero coronary artery calcium (CAC). Methods A total of 176 consecutive patients with NSTE-ACS who underwent preprocedural CCTA and OCT were studied. Patients were divided into two groups according to their CAC (zero-CAC and non-zero-CAC groups). Baseline characteristics, CCTA and OCT findings were compared between these two groups. Results The prevalence of patients with zero-CACS was 15.9% (28/176). Patients in zero CAC group were younger (mean age, 55 vs. 65 years, P<0.001) and had a lower prevalence of diabetes (10.7 vs 37.2%, P=0.012) than non-zero CAC group. In zero CAC group, the lower prevalence of napkin ring sign (3.5% vs. 28.4%, P=0.028), smaller LV mass index (77.7 vs. 83.9, P=0.04), lower prevalence on spotty calcification (0 vs. 83.8%, P<0.001), lower epicardial fat volume (111.3 vs. 142.6 cm3, P=0.025), and lower pericoronary adipose tissue attenuation (−71.5 vs. −70.2 HU, P=0.07) on CCTA were observed. On OCT, the frequency of plaque erosion (82.1 vs. 44.6%, P<0.001) was significantly higher in zero-CACS group. The prevalence of lipid-rich plaque (46.4 vs. 86.5%, P<0.001), thin-cap fibroatheroma (17.9 vs. 46%, P=0.006), macrophage accumulation (46.4 vs. 81.8%, P<0.001) and cholesterol crystal (7 vs. 41.9%, P<0.001) were all significantly lower in zero-CAC group. Conclusions Zero CAC NSTE-ACS was not rare. Zero-CAC NSTE-ACS was characterized by specific phenotypes defined by the combined assessment of CCTA and OCT. Further studies are warranted if these characteristics of NSTE-ACS on preprocedural imaging studies provide prognostic information or guidance of a specific therapeutic approach. Funding Acknowledgement Type of funding sources: None.