Objectives To characterize the morphological features of plaque erosion and calcified nodule in patients with acute coronary syndrome (ACS) by optical coherence tomography (OCT). Background Plaque erosion and calcified nodule have not been systematically investigated in vivo. Methods One hundred and twenty-six patients with ACS who had undergone pre-intervention OCT imaging were included. The culprit lesions were classified as plaque rupture (PR), erosion (OCT-erosion), calcified nodule (OCT-CN), or others using a new set of diagnostic criteria for OCT. Results The incidences of PR, OCT-erosion, and OCT-CN were 43.7%, 31.0%, and 7.9%, respectively. Patients with OCT-erosion were the youngest compared with those with PR and OCT-CN (53.8±13.1 years vs. 60.6±11.5 years, 65.1±5.0 years, p=0.005). Compared with patients with PR, presentation with non-ST-segment elevation ACS (NSTE-ACS) was more common in patients with OCT-erosion (61.5% vs. 29.1%, p=0.008) and OCT-CN (100% vs. 29.1%, p<0.001). OCT-erosion had a lower frequency of lipid plaque (43.6% vs. 100%, p<0.001), thicker fibrous cap (169.3±99.1 μm vs. 60.4±16.6 μm, p<0.001), and smaller lipid arc (202.8±73.6° vs. 275.8±60.4°, p<0.001) than PR. The diameter stenosis was least severe in OCT-erosion followed by OCT-CN and PR (55.4±14.7% vs. 66.1±13.5% vs. 68.8±12.9%, p<0.001). Conclusions OCT is a promising modality for identifying OCT-erosion and OCT-CN in vivo. OCT-erosion is a frequent finding in patients with ACS, especially in those with NSTE-ACS and younger patients. OCT-CN is the least common etiology for ACS and is more common in older patients.

For patients with ACS caused by plaque erosion, conservative treatment with anti-thrombotic therapy without stenting may be an option.

The results of this prospective multicenter study demonstrate that FD-OCT provides accurate and reproducible quantitative measurements of coronary dimensions in the clinical setting.

The aims of this study were (1) to evaluate the incidence of poststent findings detected by OCT from multicenter experience, (2) to correlate these poststent findings with 1-year device-oriented clinical end points (DoCEs), including cardiac death, target vessel-related myocardial infarction, target Background-Optical coherence tomography (OCT) was recently introduced to optimize percutaneous coronary intervention. However, the exact incidence and significance of poststent OCT findings are unknown. Methods and Results-A total of 900 lesions treated with 1001 stents in 786 patients who had postprocedure OCT imaging were analyzed to evaluate the incidence of poststent OCT findings and to identify the OCT predictors for device-oriented clinical end points, including cardiac death, target vessel-related myocardial infarction, target lesion revascularization, and stent thrombosis. Patients were followed up to 1 year. Stent edge dissection was detected in 28.7% of lesions, and incomplete stent apposition was detected in 39.1% of lesions. The incidences of smooth protrusion, disrupted fibrous tissue protrusion, and irregular protrusion were 92.9%, 61.0%, and 53.8%, respectively. Small minimal stent area, defined as a lesion with minimal stent area <5.0 mm 2 in a drug-eluting stent or <5.6 mm 2 in a bare metal stent, was observed in 40.4% of lesions. One-year device-oriented clinical end points occurred in 33 patients (4.5%). Following adjustment, irregular protrusion and small minimal stent area were independent OCT predictors of 1-year device-oriented clinical end points (P=0.003 and P=0.012, respectively). Conclusions-Abnormal