BACKGROUND Coronary calcification is associated with high risk for cardiovascular events. However, its impact on plaque vulnerability is incompletely understood. In the present study we defined the intrinsic calcification angle (ICA) as the angle externally projected by a vascular calcification and analyzed its role as novel feature of coronary plaque vulnerability in patients with type 2 diabetes. METHODS Optical coherence tomography was used to determine ICA in 219 calcifications from 56 patients with stable coronary artery disease (CAD) and 143 calcifications from 36 patients with acute coronary syndrome (ACS). We then used finite elements analysis to gain mechanistic insight into the effects of ICA. RESULTS Minimal (139.8 ± 32.8° vs. 165.6 ± 21.6°, p < 0.001) and mean ICA (164.1 ± 14.3° vs. 176.0 ± 8.4°, p < 0.001) were lower in ACS vs. stable CAD patients. Mean ICA predicted ACS with very good diagnostic efficiency (AUC = 0.840, 95% CI 0.797-0.882, p < 0.001, optimal cut-off 175.9°); younger age (OR 0.95 per year, 95% CI 0.92-0.98, p = 0.002), male sex (OR 2.18, 95% CI 1.41-3.38, p < 0.001), lower HDL-cholesterol (OR 0.82 per 10 mg/dl, 95% CI 0.68-0.98, p = 0.029) and ACS (OR 14.71, 95% CI 8.47-25.64, p < 0.001) were determinants of ICA < 175.9°. A lower ICA predicted ACS (OR for 10°-variation 0.25, 95% CI 0.13-0.52, p < 0.001) independently from fibrous cap thickness, presence of macrophages or extension of lipid core. In finite elements analysis we confirmed that lower ICA causes increased stress on a lesion's fibrous cap; this effect was potentiated in more superficial calcifications and adds to the destabilizing role of smaller calcifications. CONCLUSION Our clinical and mechanistic data for the first time identify ICA as a novel feature of coronary plaque vulnerability.

中文翻译：

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内在钙化角度：2型糖尿病患者中脆弱的冠状动脉斑块的新特征：光学相干断层扫描研究。

背景技术冠状动脉钙化与心血管事件的高风险有关。但是，其对斑块易损性的影响尚不完全清楚。在本研究中，我们将固有钙化角（ICA）定义为由血管钙化向外投射的角度，并分析了其作为2型糖尿病患者冠状动脉斑块易损性的新特征的作用。方法采用光学相干断层扫描法测定56例稳定冠状动脉疾病（CAD）患者的219个钙化和36例急性冠状动脉综合征（ACS）患者的143个钙化。然后，我们使用有限元分析来获得对ICA影响的机械分析。结果ACS相比最低（139.8±32.8°vs. 165.6±21.6°，p <0.001）和平均ICA（164.1±14.3°vs. 176.0±8.4°，p <0.001）更低。稳定的CAD患者。平均ICA预测的ACS具有非常好的诊断效率（AUC = 0.840，95％CI 0.797-0.882，p <0.001，最佳截止175.9°）; 年龄较小（OR 0.95 /每年，95％CI 0.92-0.98，p = 0.002），男性（OR 2.18，95％CI 1.41-3.38，p <0.001），HDL-胆固醇较低（OR 0.82 / 10 mg / dl ，95％CI 0.68-0.98，p = 0.029）和ACS（OR 14.71，95％CI 8.47-25.64，p <0.001）是ICA <175.9°的决定因素。较低的ICA预测ACS（与10°差异0.25对应，OR为95％CI 0.13-0.52，P <0.001），与纤维帽的厚度，巨噬细胞的存在或脂质核心的延伸无关。在有限元分析中，我们证实了较低的ICA会增加病变的纤维帽上的应力。这种作用在更浅的钙化中得到加强，并增加了较小钙化的不稳定作用。