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In vivo imaging of plaque instability has been considered to have a great potential to predict future coronary events and evaluate the stabilization effect of novel anti-atherosclerotic medical therapies.Currently, there are several intravascular imaging modalities which enable to visualize plaque components associated with its vulnerability. These include virtual histology intravascular ultrasound (VH-IVUS), integrated backscatter IVUS (IB-IVUS), optical coherence tomography (OCT), near-infrared spectroscopy and coronary angioscopy. Recent studies have shown that these tools are applicable for risk stratification of cardiovascular events as well as drug efficacy assessment. However, several limitation exists in each modality.The current review paper will outline advantages and limitation of VH-IVUS, IB-IVUS, OCT, NIRS and coronary angioscopy imaging.

Although current guidelines have highlighted the importance of evidence-based optimal medical therapy (OMT) in patients with previous coronary artery bypass grafting (CABG), the effect of OMT on post-CABG patients requiring secondary coronary revascularization on prognosis remains unknown. We sought to examine the impact of OMT on post-CABG patients who underwent percutaneous coronary intervention (PCI) as secondary revascularization. A total of 632 consecutive post-CABG patients who underwent PCI between 2001 and 2013 at our hospital (84% men, median age 71 years) were divided into 2 groups: patients who were discharged with OMT and patients who were discharged without OMT (non-OMT). OMT was defined as the combination of an antiplatelet agent, statin, β blocker, and angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. Despite having a higher prevalence of clinical comorbidities, patients with OMT (n = 163) had a lower prevalence of all-cause death than those without OMT (n = 469) during a median follow-up of 95 months (OMT group 21.5%, non-OMT group 34.1%, p = 0.002). Both groups had similar procedural success rates. In a propensity-matched cohort (n = 146 each), OMT was associated with lower rates of all-cause death and cardiac death than non-OMT 8 years after PCI. In multivariable analysis, OMT was an independent predictor of all-cause death (hazard ratio [HR] 0.49, 95% confidence interval [CI] 0.34 to 0.72, p <0.001). In conclusion, OMT plays a protective role and reduces all-cause death in post-CABG patients requiring subsequent PCI. Outside of the domain of coronary revascularization, OMT could be considered an essential treatment in this patient population.

Background Histopathological studies have reported the presence of cholesterol crystals in the culprit lesion in patients with sudden cardiac death. Given that cholesterol crystals themselves promote pro-inflammatory cascades, they may destabilize atherosclerotic plaques, leading to the occurrence of acute coronary events. Case summary A 60-year-old man presented with ST-segment elevation myocardial infarction. Emergent coronary angiography revealed a severely stenotic lesion (=culprit lesion) and another non-obstructive lesion in the proximal and middle segments of the left anterior descending artery (LAD), respectively. Optical coherence tomography (OCT) imaging showed that both lesions exhibited lipid-rich plaque with cholesterol crystals, and the non-obstructive lesion in the mid-LAD did not have a thin fibrous cap (its thickness = 230 μm). A drug-eluting stent was successfully implanted at the culprit lesion in the proximal LAD. On non-contrast T1-weighted magnetic resonance imaging performed 10 days after percutaneous coronary intervention (PCI), a high-intensity signal was identified at the non-obstructive mid-LAD lesion. This lesion was medically managed with aspirin, clopidogrel, and rosuvastatin due to the absence of myocardial ischaemia. However, 12 months after PCI, the patient was hospitalized again due to unstable angina pectoris. Coronary angiography revealed substantial progression of the mid-LAD lesion. Optical coherence tomography imaging prior to the second PCI showed a severely narrowed lesion containing cholesterol crystals and covered by organized thrombus. This lesion harbored an extensive amount of lipidic materials on near-infrared spectroscopy (maximum 4-mm lipid core burden index = 809). Discussion In our case, atherosclerotic plaques containing cholesterol crystals was associated with the occurrence of acute coronary syndrome. Our findings suggest that plaque with cholesterol crystals is a potential precursor to future acute coronary events.

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