肥厚型心肌病节段性心肌纤维化与微循环障碍之间的关系研究

Relationship between segmental myocardial fibrosis and coronary microvascular dysfunction in hypertrophic cardiomyopathy

目的:应用心脏磁共振(CMR)技术评估并探索肥厚型心肌病(HCM)心肌组织特征与局部微血管功能之间的关系。方法:入选2018年1月—2019年12月在我院由心脏超声确诊的HCM患者23例(HCM组),健康志愿者19例(对照组)。所有研究对象均完成CMR检查,包括左心室短轴电影成像、T1mapping成像及静息心肌首过灌注成像等。应用第三方专业软件CVI42分析图像,分析得出左心室心功能参数、整体以及16个心肌节段(美国心脏病协会左室心肌分段法)的Native T1值和静息心肌灌注参数:最大信号强度(SI-max),最大信号强度所对应的时间(Time-max),心肌信号强度的最大斜率(Slope-max),并比较对照组和HCM组之间的差异。将HCM组的心肌节段(378段)分为HCM纤维化节段(Native T1≥1288ms,150段)和HCM非纤维化节段(Native T1<1288ms,228段)两个亚组,比较其与对照组心肌节段之间静息心肌灌注参数的差异。结果:相比较于对照组,HCM组的整体Native T1值和Time-max延长,Slope-max和SI-max下降(P<0.005);较对照组节段和HCM非纤维化节段,HCM纤维化节段Slope-max、SI-max显著降低,Time-max明显增加(P<0.005);此外,HCM非纤维化节段中Slope-max较对照组节段降低,Time-max较对照组节段增加,且差异也具有统计学意义。结论:CMR可用于早期检测HCM患者的微循环障碍和心肌纤维化。微循环障碍同时存在于HCM纤维化和非纤维化节段,这表明了在心肌发生纤维化之前,其微循环功能已经受损。

Objective: To evaluate and explore the relationship between cardiac tissue characteristic and local micro-vascular function in hypertrophic cardiomyopathy(HCM) by Cardiovascular magnetic resonance(CMR). Methods: The 23 HCM patients(HCM group) diagnosed by echocardiography in our hospital from January 2018 to December 2019 and 19 healthy volunteers(control group) were enrolled. All cases underwent CMR including short axis cine, T1 mapping imaging and first-pass myocardial perfusion. Cvi42, a third-party image processing software, was applied to analyze images. Perfusion parameters were assessed, including maximal signal intensity(SI-max), time to maximal signal intensity(Time-max), maximal upslope of myocardial intensity enchantment(Slope-max), the cardiac function parameters, the Native T1 value of 16 myocardial segments of left ventricular, as well as of the global myocardium. The 378 segments in HCM group were divided into HCM fibrotic segments(Native T1≥1288 ms, N=150) and HCM non-fibrotic segments(Native<1288 ms, N=228). The differences in perfusion parameters were compared among control group segments, HCM fibrotic segments and HCM non-fibrotic segments. Results: The global Native T1 and Time-max prolonged, but Slope-max and SI-max decreased in HCM group when comparing with control group(P<0.001). Compared with HCM non-fibrotic segments and control group segments, the Slope-max and SI-max decreased, and Time-max increased in HCM fibrotic segments(P<0.005). Additionally, the Slope-max and Time-max also showed statistically significant difference between HCM non-fibrotic segments and control group segments(all P<0.001). Conclusion: CMR could facilitate the early evaluation of coronary microvascular dysfunction and fibrosis in HCM.