二维斑点追踪成像技术评价冠状动脉慢血流患者左室心肌分层应变

 目的  应用二维斑点追踪成像技术(two-dimensional speckle tracking echocardiography, 2D-STE)分析冠状动脉慢血流(coronary slow flow, CSF)患者左室心肌分层应变, 研究2D-STE在临床上评估CSF患者左室各层心肌收缩功能的准确性及应用价值。方法  设定CSF组41例(CSF患者)及对照组59例(冠状动脉造影检查结果正常者), 分别采集存储6个切面观(心尖左室长轴、心尖四腔、心尖两腔及二尖瓣、乳头肌、心尖水平左室短轴)的动态二维超声图像, 利用软件于各切面观脱机分析CSF组和对照组左室3层心肌(心内膜下、中层和心外膜下)的分层应变, 分别计算出两组左室3层心肌整体纵向应变(global longitudinal strains, GLS)和整体环向应变(global circumferential strains, GCS)以及相应的跨壁应变梯度△GLS、△GCS。结果  CSF组及对照组左室3层心肌(心内膜下层、中层、心外膜下层)GLS和GCS均保持由内向外逐层递减的跨壁梯度特征; CSF组GLS、△GLS 较对照组减低, 差异有统计学意义(P<0.05), 尤以心内膜下层GLS和△GLS降低更为显著(P<0.001); CSF组GCS、△GCS减低, 但与对照组相比差异无统计学意义。应用ROC曲线计算分层应变参数预测CSF左室收缩功能, △GLS的曲线下面积最大(AUC=0.766, P<0.001), 当△GLS取截断值为-4.87%时, 灵敏度及特异度分别可达66.7%及76.3%。结论  2D-STE可通过评估心肌分层应变识别CSF患者左室3层心肌收缩功能受累的差异(心内膜下层为甚)。心肌纵向应变跨壁梯度△GLS可早期识别CSF患者的心肌收缩功能异常, 具有临床诊断的应用前景。

Assessment of left ventricular layer-specific myocardial strain in patients with coronary slow flow by two-dimensional speckle tracking echocardiography

Objective  To discuss the clinical value and accuracy of two-dimensional speckle tracking echocardiography (2D-STE) for the evaluation of left ventricular systolic function of the coronary slow flow (CSF) by assessing left ventricular layer-specific myocardial strains in patients with CSF. Methods  CSF group contained 41 patients with CSF, and 59 patients with normal coronary angiography results were involved as the control group. All 2-dimensional (2D) echocardiographic images from 6 standard views (apical views of long-axis, 4-chamber, and 2-chamber; parasternal short-axis views of mitral valve, papillary muscle, and apical level) were acquired for offline analysis. Layer-specific strain from endocardium, mid-myocardium and epicardium of LV wall was analyzed by 2D-STE software. Layer-specific global longitudinal strains (GLS) and global circumferential strains (GCS) were assessed at endocardium, midmyocardium and epicardium by 2D-STE. The transmural gradient between endocardial and epicardial (△GLS, △GCS) were calculated. Results  GLS and GCS of each myocardium showed gradient descent, which is subendocardium>midmyocardium>subepicardium in both CSF group and control group. As comparing to the control group, GLS and △GLS in CSF group were significantly lower (P<0.05); especially the endocardial GLS and △GLS (P<0. 001 ). There were no significant difference in both GCS and △GCS between CSF group and control group. The AUC of △GLS was biggest (AUC=0.766, P<0. 001), and when the cut off value was -4. 87%, the sensitivity and the specificity was 66.7% and 76.3%, respectively. Conclusions  2D-STE can identify left ventricular 3-layer contractility (especially the subendocardium) by assessing left ventricular layer-specific myocardial strains in patients with CSF. Meantime, lognitudinal transmural gradient △GLS can identify the abnormity of left ventricular contractility in patients with CSF and have the promising prospect of clinical diagnosis.