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A 45-year-old premenopausal woman presented with acute myocardial infarction (MI). An intravascular ultrasound (IVUS) revealed that her distal right coronary artery was occluded by spontaneous coronary artery dissection (SCAD). She did not have any specific condition related to SCAD. At follow-up cardiac catheterization, an acetylcholine provocation test was applied to examine the etiology of SCAD, and definitive coronary vasospasm was induced with chest symptoms and significant electrocardiographic change. A Ca-channel blocker was administered and since then chest pain has subsequently so far been relieved. The current case suggests the significance of the IVUS in detecting etiology of MI in younger patients and the potential association between SCAD and coronary vasospasm.

Despite current standards of care aimed at achieving targets for low-density lipoprotein cholesterol (LDL-C), many patients remain at high residual risk of cardiovascular events. We sought to assess the LDL-C-dependent differences in culprit intravascular ultrasound (IVUS) morphologies and clinical characteristics in patients with acute coronary syndrome (ACS). Eighty-six consecutive ACS patients whose culprit lesions imaged by preintervention IVUS were divided into two groups based on the fasting LDL-C level on admission: a low-LDL-C group (LDL-C <2.6 mmol/l, n = 45) and a high-LDL-C group (LDL-C ≥2.6 mmol/l, n = 41). Patients with stable angina with LDL-C <2.6 mmol/l (n = 30) were also enrolled as an age- and gender-matched control. The low-LDL-C ACS group was significantly older (72 ± 12 vs 64 ± 14 years, P = 0.007) and more diabetic (47 % vs 15 %, P = 0.001). Importantly, IVUS morphologies were comparable between low- and high-LDL-C ACS groups (all P not significant), whereas culprit plaque was more hypoechoic and less calcified in the low-LDL-C ACS group than in the low-LDL-C stable angina group. Furthermore, compared with the low-LDL-C ACS nondiabetic group, the low-LDL-C ACS diabetic group was more obese, more triglyceride rich (1.3 ± 0.6 vs 0.9 ± 0.4 mmol/l, P = 0.003), and more endothelially injured, but no different for the culprit IVUS morphologies. In multivariate analysis, diabetes was independently associated with a low LDL-C level on admission in patients with ACS. There was no relationship between the LDL-C level at onset and culprit-plaque IVUS morphologies in ACS patients, although culprit plaque in the low-LDL-C ACS group was more vulnerable than in the low-LDL-C stable angina group. In patients with low-LDL-C levels, diabetes with atherogenic dyslipidemia might be the key residual risk.

DES implantation would be associated with iMap-derived necrotic and less-fibrotic neointimal formation. In vivo iMap evaluation of neointimal tissue may provide useful information in detecting impaired healing after stenting.

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