分层应变显像检测冠脉微血管障碍的左心室整体及节段收缩功能的变化特征

Coronary microvascular dysfunction(CMVD) is a common type of coronary heart disease which could directly lead to myocardial ischemia. Left ventricular(LV) function plays an important role in the severity assessment and prognosis of the patients with CMVD. In the case of CMVD, the impairment of myocardial perfusion may be distributed in the myocardium in a scattered manner. This distribution of perfusion abnormalities can provide a plausible explanation for the difficulties in obtaining objective evidence of myocardial ischemia in most patients when standard diagnostic methods are used. 2D-STI layer-specific strain imaging is a well-developed echocardiographic technique with the advantage of displaying the 3 layers myocardial function. This advantage makes it superior to conventional 2-dimensional method in LV function assessment. Recent research demonstrated that LV global and regional systolic function can be effectively evaluated by 2D-STI layer-specific strain imaging. In our pilot study, we found that the LV 3 layer global longitudinal strains were impaired in patients with chronic CMVD. The feasibility and reproducibility of 2D-STI layer-specific strain imaging was good in our clinical and experimental studies. Therefore we apply for the approval of this present study, aiming to :①assess the correlation between 2D-STI layer-specific strain parameters and pathological examination, MRI parameters, biochemical indexes in different degree of microembolization mini-swine models; ②explore the relationship between 2D-STI layer-specific strain parameters and TIMI frame count , biochemical indexes in serum in patients with acute and chronic CMVD; ③record the changes of 2D-STI layer-specific strain parameters during follow-up. The results of our study might provide a noninvasive tool for LV global and regional systolic function assessment and efficacy evaluation in patients with acute and chronic CMVD.

冠脉微血管障碍（CMVD）可以直接导致心肌缺血，左心室功能与其病情评估及预后密切相关，但CMVD引起的心肌缺血在心肌各层间的分布是分散不均匀的，传统的影像手段无法检测出这种稀疏分布的心肌缺血，新近研究显示二维斑点追踪（2D-STI）分层应变技术能有效评价左心室的整体和节段收缩功能，我们的前期研究显示慢性CMVD患者左室三层心肌的整体纵向应变较对照组减低，2D-STI分层应变技术在慢性CMVD患者和动物模型中有较高的可行性和重复性。本研究拟使用2D-STI分层应变技术评价急性和慢性CMVD左心室整体和节段收缩功能的不同之处，在猪微栓塞模型中探索分层应变参数与MRI测量值、血生化指标、心肌组织病理的一致性，在急性和慢性CMVD患者中分析分层应变参数与TIMI血流帧数值、血生化指标的相关性和长期随访的变化趋势，为急性和慢性CMVD患者左心室整体和节段功能的评估和疗效随访提供新的无创性指标。

冠脉微血管障碍（CMVD）可以直接导致心肌缺血，左心室功能与其病情评估及预后密切相 关，但CMVD引起的心肌缺血在心肌各层间的分布是分散不均匀的，传统的影像手段无法检测出这种稀疏分布的心肌缺血，新近研究显示二维斑点追踪（2D-STI）分层应变技术能有效评价左心室的整体和节段收缩功能，本研究使用2D-STI分层应变技术评价急性和慢性CMVD左心室整体和节段收缩功能的不同之处 ，在猪微栓塞模型中探索分层应变参数与MRI测量值、血生化指标、心肌组织病理的一致性， 在急性和慢性CMVD患者中分析分层应变参数与TIMI血流帧数值、血生化指标的相关性和长期随访的变化趋势。动物实验结果显示10万微球的微栓塞组术后4-6h左室三层周向应变较术前显著减低（-21.8±4.3% vs-12.8±4.0%，-12.5±4.0%vs-8.5±3.8%，-7.4±3.7%vs-6.3±3.6%，P<0.05）；临床研究结果显示分层GLS和受累冠脉负相关（r=-0.44，-0.43，-0.35，P均＜0.05）和TFC负相关（r=-0.31，-0.29，-0.45，P均＜0.05），CMVD组系统血管阻力(SVRI)高于对照组（4978.6±1223.2 vs 4223.7±1200.3，P=0.012）， 动脉顺应性指数（ACI）低于对照组，ACI和分层GLS负相关（r=-0.42，-0.44，-0.55，P均＜0.05）；LV-GLS-endo识别CSF患者亚临床心肌损伤的曲线下面积最大（AUC=0.867,P＜0.001）,预测CMVD患者亚临床心肌损伤的敏感性71.2%，特异性93.9%。我们的研究为CMVD患者左心室整体和节段功能的评估和疗效随访提供了新的无创性指标。