Okamura Akihiko, Okura Hiroyuki, Iwai Saki, Kyodo Atsushi, Kamon Daisuke, Hashimoto Yukihiro, Ueda Tomoya, Soeda Tsunenari, Watanabe Makoto, Saito Yoshihiko
Department of Cardiovascular Medicine, Nara Medical University, Kashihara, Japan.
Department of Cardiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan.
Int J Cardiovasc Imaging. 2022 May;38(5):1169-1176. doi: 10.1007/s10554-021-02497-5. Epub 2022 Jan 11.
Myocardial bridge (MB) is less commonly documented by angiography than autopsy. Optical coherence tomography (OCT) may be useful to detect angiographically undetectable MB. To investigate OCT characteristics of MB, 86 LAD vessels were imaged by OCT. MB was defined as presence of intermediate optical intensity, "fine" layer surrounding coronary artery by OCT. Frequency and characteristics of the angio-detectable and angio-undetectable but OCT-detectable MB were investigated. In a subset of patients with angio-detectable MB, cyclic changes in coronary arterial dimensions were analyzed. OCT detected MB in 44 of 86 (51%). Arc of the MB was significantly larger (334.8 ± 58.5° vs. 268.4 ± 92.1°, P = 0.008) and length was significantly longer (22.6 ± 11.7 mm vs. 14.5 ± 8.1 mm, P = 0.014) in angio-detectable MB than OCT-detectable but angio-undetectable MB. Both vessel (6.8 ± 1.5 to 5.3 ± 1.0 mm, P = 0.035) and lumen area (4.4 ± 1.5 to 3.1 ± 0.7 mm, P = 0.040) decreased significantly from diastole to systole. Adventitial (0.08 ± 0.03 to 0.08 ± 0.02 mm, P = 0.828) and intima + plaque thickness (0.12 ± 0.05 to 0.10 ± 0.03 mm, P = 0.398) did not change significantly during cardiac cycle. On the other hand, medial thickness increased significantly from diastole to systole (0.08 ± 0.03 to 0.12 ± 0.03 mm, P = 0.022). In conclusion, MB is frequently detected as intermediate intensity, fine layer by OCT. During systole, vessel and lumen size decrease with increased medial thickness. Therefore, we should be careful for OCT interpretation of the coronary arteries with MB.
心肌桥（MB）在血管造影中的记录比尸检中少见。光学相干断层扫描（OCT）可能有助于检测血管造影无法检测到的MB。为了研究MB的OCT特征，对86条左前降支血管进行了OCT成像。MB被定义为OCT显示的中等光学强度的“精细”层围绕冠状动脉。研究了血管造影可检测到的和血管造影不可检测但OCT可检测到的MB的频率和特征。在一部分血管造影可检测到MB的患者中，分析了冠状动脉尺寸的周期性变化。OCT在86例中的44例（51%）检测到MB。血管造影可检测到的MB的MB弧度明显更大（334.8±58.5°对268.4±92.1°，P = 0.008），长度明显更长（22.6±11.7 mm对14.5±8.1 mm，P = 0.014），比OCT可检测到但血管造影不可检测到的MB。从舒张期到收缩期，血管（6.8±1.5至5.3±1.0 mm，P = 0.035）和管腔面积（4.4±1.5至3.1±0.7 mm，P = 0.040）均显著减小。外膜厚度（0.08±0.03至0.08±0.02 mm，P = 0.828）和内膜+斑块厚度（0.12±0.05至0.10±0.03 mm，P = 0.398）在心动周期中无显著变化。另一方面，中层厚度从舒张期到收缩期显著增加（0.08±0.03至0.12±0.03 mm，P = 0.022）。总之，MB常被OCT检测为中等强度的精细层。在收缩期，血管和管腔尺寸减小，中层厚度增加。因此，我们在对有MB的冠状动脉进行OCT解释时应谨慎。
