Morikawa Tomoyuki, Hiro Takafumi, Mineki Takashi, Kojima Keisuke, Kogo Takaaki, Iida Korehito, Akutsu Naotaka, Murata Nobuhiro, Sudo Mitsumasa, Kitano Daisuke, Fukamachi Daisuke, Okumura Yasuo
Division of Cardiology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-Kamicho, Itabashi-ku, Tokyo, 173-8610, Japan.
Heart Vessels. 2025 Jan;40(1):16-25. doi: 10.1007/s00380-024-02439-w. Epub 2024 Aug 22.
The main cause of acute coronary syndrome (ACS) is plaque rupture and thrombus formation. However, it has not been fairly successful to identify vulnerable plaque to rupture using conventional parameters of intravascular imaging modalities. Fractal analysis is one of the mathematical models to examine geometrical features of picture image using a specific parameter called as fractal dimension (FD) which suggests geometric complexity of the image. This study examined FD of the optical coherence tomography (OCT)-derived images of the culprit plaque in patients with ACS vs stable angina pectoris (SAP) to evaluate the feasibility of FD for identifying vulnerable coronary plaques prone to provoke ACS distinguished from stable plaques only provoking SAP. We examined 65 cases (34 ACS patients, 31 SAP patients) in which the culprit lesion was imaged by OCT before percutaneous coronary intervention in patients with ACS and SAP. The culprit plaque lesion in the ACS group had a significantly larger mean lipid arc (203.8 ± 39.4° vs 152.3 ± 34.5°, p < 0.001) and a larger lipid plaque length (12.6 ± 5.1 mm vs 7.7 ± 2.7 mm, p < 0.001) and a thinner fibrous cap thickness (75.3 ± 22.3 μm vs 134.8 ± 53.2 μm, p < 0.001) than those in the SAP group. The prevalence of OCT-derived macrophage infiltration (Mph) in the entire culprit coronary vessel as well as that of the OCT-derived thin-cap fibroatheroma (TCFA) at the culprit lesion were significantly greater in the ACS group than those in the SAP group, respectively (Mph: 61.8% vs 35.5%, p = 0.048; TCFA: 44.1% vs 6.4%, p < 0.001). The FD of culprit plaque in the ACS group was significantly greater than in the SAP group (2.401 ± 0.073 vs 2.341 ± 0.051, p < 0.001). In multivariate regression analysis, the presence of Mph was a significant determinant of FD (regression coefficient estimate 0.049, CI 0.018-0.079, p = 0.002). The FD of OCT-derived image of culprit coronary plaque in the ACS group was significantly greater than that in the SAP group, indicating that the culprit plaque in ACS were structurally more complex. Therefore, fractal analysis of coronary OCT images might be clinically useful for identifying coronary plaques prone to provoke ACS.
急性冠状动脉综合征（ACS）的主要病因是斑块破裂和血栓形成。然而，使用血管内成像模式的传统参数来识别易破裂的易损斑块并不十分成功。分形分析是一种数学模型，它使用一个称为分形维数（FD）的特定参数来检查图像的几何特征，该参数反映了图像的几何复杂性。本研究检测了ACS患者与稳定型心绞痛（SAP）患者中罪犯斑块的光学相干断层扫描（OCT）衍生图像的FD，以评估FD用于识别易引发ACS的易损冠状动脉斑块（有别于仅引发SAP的稳定斑块）的可行性。我们检测了65例患者（34例ACS患者，31例SAP患者），这些患者在接受经皮冠状动脉介入治疗前，其罪犯病变均通过OCT成像。ACS组罪犯斑块病变的平均脂质弧明显更大（203.8°±39.4° vs 152.3°±34.5°，p<0.001）、脂质斑块长度更长（12.6±5.1mm vs 7.7±2.7mm，p<0.001）、纤维帽厚度更薄（75.3±22.3μm vs 134.8±53.2μm，p<0.001），均大于SAP组。ACS组整个罪犯冠状动脉血管中OCT衍生的巨噬细胞浸润（Mph）患病率以及罪犯病变处OCT衍生的薄帽纤维粥样斑块（TCFA）患病率均分别显著高于SAP组（Mph：61.8% vs 35.5%，p=0.048；TCFA：44.1% vs 6.4%，p<0.001）。ACS组罪犯斑块的FD显著大于SAP组（2.401±0.073 vs 2.341±0.051，p<0.001）。在多因素回归分析中，Mph的存在是FD的一个重要决定因素（回归系数估计值0.049，CI 0.018 - 0.079，p=0.002）。ACS组罪犯冠状动脉斑块的OCT衍生图像的FD显著大于SAP组，表明ACS中的罪犯斑块在结构上更复杂。因此，冠状动脉OCT图像的分形分析可能在临床上有助于识别易引发ACS的冠状动脉斑块。
