18F-FDG PET心肌代谢显像对缺血性心肌病CRT无应答的预测及相关机制的实验研究

Cardiac resynchronization therapy (CRT) has been shown to be an important treatment modality for the management of heart failure, but there is unfortunately still a significant amount of patients who do not respond to this therapy, particularly patients with ischemic cardiomyopathy. Recent research has been conducted that myocardial viability and left ventricular mechanical dyssynchrony have been proposed as determinants of CRT response in ischemic cardiomyopathy recipients. Gated myocardial perfusion imaging(GMPI) is commonly used in the evaluation of myocardial viability and left ventricular mechanical synchrony. But the capability of evaluating myocardial viability by GMPI is less than myocardial 18F-FDG PET imaging, and our previous study found that myocardial 18F-FDG PET imaging moderately correlated with GMPI in assessing left ventricular mechanical dyssynchrony. So we hypothesis that myocardial 18F-FDG PET imaging is superior to GMPI in predicting CRT non-responders. In our study, We will establish the model of ischemic cardiomyopathy heart failure in pig, to explore the effect of the extent and location of viable myocardium or scar myocardium or necrotic myocardium and local mechanical dyssynchrony detected by myocardial 18F-FDG PET imaging for CRT response, so as to reveal whether myocardial 18F-FDG PET imaging is superior to GMPI in predicting CRT non-responders,to clarify the relationship between mechanical dyssynchrony and electrical dyssynchrony. It could lead to a better method for the prediction of no response to CRT and useful treatment stratage in ischemic cardiomyopathy with CRT through our study.

心脏再同步化治疗（CRT）是治疗心力衰竭的重要方法，但相当比例的缺血性心肌病心衰患者表现为CRT无应答。研究表明，心肌活力和左室机械同步性可能是影响缺血性心肌病CRT应答的关键因素。门控心肌灌注显像（GMPI）是目前常用的评价心肌活力和左室机械同步性的方法。但是，GMPI 评价心肌活力不及18F-FDG PET显像，并且我们的前期研究发现GMPI 和18F-FDG PET 评估左室机械同步性仅呈中度相关。因此我们推测，18F-FDG PET心肌显像预测CRT无应答可能优于GMPI。在本研究中，我们拟在猪的缺血性心肌病心衰模型，利用18F-FDG PET显像探讨存活心肌范围、部位及局部机械同步性对CRT应答的影响；分析18F-FDG PET心肌显像预测CRT无应答是否优于GMPI；并探索机械不同步与电不同步的关系。通过本研究，以期为减少缺血性心肌病的CRT无应答提供决策依据和更好的评价方法。

心脏再同步化治疗（CRT）是治疗心力衰竭的重要方法，但相当比例的缺血性心肌病心衰患者表现为CRT无应答。心肌活力、左室机械同步性以及左室最晚收缩部位是影响缺血性心肌病CRT应答的因素。准确评估存活心肌、左室机械同步性以及左室最晚收缩部位可能是破解CRT无应答的关键。门控心肌灌注显像（GMPI）和门控PET FDG心肌代谢显像（GPET FDG）是目前评价左室机械同步性和存活心肌的常用方法，GMPI或GPET FDG能否准确指导缺血性心肌病CRT左室电极植入，目前尚不明确。本研究构建巴马小型猪心肌梗死（MI）心衰模型，以GMPI作为左室收缩同步性评价的参照标准，探讨GPET FDG 评价左室收缩同步性的可行性；以GPET FDG作为评价存活心肌的金标准，探讨GMPI诊断存活心肌的效能；应用GMPI评价MI后左室机械不同步，应用Carto评价MI后左室电不同步，探讨左室机械不同步与左室电不同步的关系以及左室最晚收缩部位与左室最晚电激动部位的关系；探讨CRT左室电极分别植入于最晚收缩部位、瘢痕交界区、瘢痕区不同心肌节段时左室即刻血流动力学指标（dP/dtmax）的变化，分析缺血性心肌病CRT左室电极最佳植入部位。本项目先后完成41头巴马小型猪实验研究，研究结果发现GPET FDG和GMPI两种方法均可准确评价左室收缩同步性及存活心肌，但GMPI简便易行、有更优的卫生经济学；心肌梗死后存在左室机械不同步和左室电不同步，GMPI所得非瘢痕区的左室最晚收缩部位与Carto所得非瘢痕区最晚电激动部位基本一致。基于GMPI所得左室最晚收缩且存活心肌节段和瘢痕心肌节段，CRT左室电极植入于缺血性心肌病的左室最晚收缩且存活心肌节段可获得最佳的血流动力学改善，明显优于植入于瘢痕交界心肌节段（751.17mmHg/s ± 105.62mmHg/s，P=0.03）和瘢痕心肌节段（679.50mmHg/s ± 60.87mmHg/s，P=0.014）。本研究阐明了缺血性心肌病左室机械不同步和左室电不同步的关系以及GMPI指导CRT左室电极植入的作用，揭示GMPI可有效指导缺血性心肌病CRT左室电极植入，为缺血性心肌病CRT左室电极植入提供新的决策依据，为减少或避免缺血性心肌病CRT无应答提供了新的解决方案。

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