斑点追踪超声心动图对左心室功能的研究

【作者】 兰亭玉；

【导师】 王浩；

【作者基本信息】 北京协和医学院 ， 影像医学与核医学， 2014， 博士

【摘要】 背景与目的：现已有充分证据证明心脏再同步化治疗(CRT)对左室收缩功能的改善是有益的,但是CRT对舒张功能的影响尚存在争论。二维斑点追踪超声心动图应变率及解旋(untwisting)对舒张功能的评估价值得深入研究。我们研究的旨在应用2D-STE技术,结合目前常用的E/E’指标,探讨CRT不同反应程度患者2D-STE应变率参数和解旋(untwisting)与左室舒张功能之间的关系。方法：本研究包括70名实施心脏再同步化治疗的心力衰竭患者。所有患者均符合心脏再同步化治疗现有的纳入标准,并除外心房颤动和经胸超声图像质量不佳患者。于心脏再同步化治疗前及心脏再同步化治疗后12个月分别采集二维斑点追踪超声心动图图像。我们将病人分为如下3组：A组,CRT超声心动图和临床反应组,即随访中左室收缩末容积减少≥15%；且6分钟步行距离增加≥20%,或该试验没有实施,在无死亡和心脏移植情况下,NYHA心功能分级好转≥1级；B组,CRT仅临床反应组；C组,CRT无反应组,既未达到超声心动图反应标准,也未达到临床反应标准。以舒张早期二尖瓣血流峰值流速和二尖瓣环峰值速度的比值(E/E’)作为衡量左心室充盈的指标。应用2D-STE技术获取患者舒张期早期应变率(LSRE、CSRE、RSRE和RotRE)和舒张晚期应变率(LSRA、CSRA和RSRA和RotRA)、解旋(untwisting)参数(UTRIVR、UTRE)等反映舒张功能的参数,观察这些左室舒张功能参数于心脏再同步化治疗不同反应程度间变化差异。将2D-STE所得的评估舒张功能参数与E/E’比值进行相关性分析。选择有效参数计算受试者工作特征曲线(receiver operating characteristic curve,即ROC曲线)下面积。结果：70名患者中,41名(58.6%)患者在12个月的随访中达到了超声心动图和临床反应性的标准；15名(21.4%)患者为仅临床反应者；14名(20%)为无反应者。在A组患者中观察到大多数评估左室舒张功能的参数有所改善。B组部分常规舒张功能参数显著性改善。而在C组患者观察到逐渐恶化的E/E’值。将2D-STE所测得的舒张期应变率参数与E/E’比值分别进行线性相关分析,舒张期应变率均呈负相关,其中以LSRE的相关性最佳(r=-0.778,p<0.01)。将解旋参数与E/E’比值分别进行线性相关分析,均呈负相关,其中以UTRIVR的相关性最佳(r=-0.837,p<0.01)。以2D-STE所测舒张早期应变率及解旋参数预测CRT超声心动图反应与否,绘制ROC曲线。UTRIVR预测CRT超声心动图反应性的ROC曲线下面积最大,为0.822(p=0.032)。UTRIVR≥11.41预测CRT超声心动图反应的敏感性为73%,特异性为75%。结论：2D-STE的舒张期应变率指标和解旋参数可以准确评估CRT不同反应程度患者的舒张功能变化差异。其中UTRIVR与E/E’相关性优于其他参数,且与E/E’比值关系更密切,预测CRT超声心动图反应与否价值更大,可能作为评价舒张功能的更为敏感指标。目的：为了减少起搏器电极导线相关并发症,相关研究人员开发出了无导线起搏器。无导线起搏器的主要优点是它可以经皮植入多个位置,减少感染和血管阻塞等并发症。本研究应用RT-3D STE超声心动图技术,对两组动物的左心室整体功能进行比较,探讨无导线起搏器的安全性和可行性,并验证RT-3D STE参数对评估左室收缩功能的可行性和有效性。方法：本研究对象为体重为45-55kg的中华小型猪。实验组动物将依次植入2个无导线起搏器；对照组动物将依次植入带有2根电极导线的常规起搏器。上述装置分次植入,植入间期为4周。在静息状态下,用三维斑点追踪超声心动图评估所有动物左心室的整体三维应变。纵向应变、环形应变、面积应变和径向应变以百分数来表示。同时于植入后1个月、3个月和6个月时,评估无导线起搏器和常规起搏器起搏参数差异及工作状态下与未工作状态下左心室功能的变化。当植入完设备随访6个月后,处死实验动物后,取出心脏,暴露右心室内无导线起搏装置或电极导线。配合使用标尺对右心室中上述装置进行拍照记录。准确测量每个植入装置与心脏组织间形成的纤维粘连物的长度。同时验证RT-3D STE参数对评估左室收缩功能的可行性和有效性,并结合目前常用的左室射血分数,分析RT-3D STE参数与它的相关性。结果：两组动物一般情况及常规超声心动图各项指标均无显著性差异。实验组和对照组的动物在植入术前及术后纵向应变、环形应变、面积应变和径向应变上没有明显的差别(P>0.05)。在两组试验动物中,起搏器工作状态和未工作状态下,无导线起搏器组动物左心室整体应变值未见明显差别,常规起搏器组左心室整体应变值未见显著性变化,组间对比未见有统计学意义差别。无导线起搏器的起搏参数随着时间的延长比较稳定。在随访期间,无导线起搏器组无并发症发生,常规起搏器组有1只猪(10%)发生1根导线脱位。RT-3D STE的三维应变值参数在观察者间及观察者内有较好的一致性。RT-3D STE与左室EF值的相关性：在所有的应变值参数中,GAS与左室射血分数有较高的相关性(r=0.914,p<0.01)。组织结果显示,无导线起搏器上的纤维组织明显短于导线电极上的纤维组织(p<0.05)。结论：本动物试验初步验证了单腔无导线起搏器是安全、可行的,因此可以把无导线起搏器作为一种替代技术,特别是对于患导线相关并发症风险较高的患者提供帮助。同时本研究验证了RT-3D STE技术评估左心室收缩功能的有效性,证实了GAS可作为除EF值以外评估左室收缩功能的可靠指标。更多还原

【Abstract】 Objective:we have sufficient evidences to prove that cardiac resynchronization therapy (CRT) have beneficial effects on left ventricular systolic function, but the effects of CRT on diastolic function remains controversial. Strain rate and untwisting of two-dimensional speckle tracking echocardiography on the evaluation of diastolic function is worth further study. In combination with traditional E/E’,we sought to explore the value of2D-STE derived strain rate parameters in the assessment of left ventricular diastolic function of different degree of response in patients with CRT.Methods:Seventy heart failure patients who under took cardiac resynchronization therapy were enrolled. Before cardiac resynchronization therapy and after cardiac resynchronization therapy for12months, the patients were underwent two dimensional speckle tracking echocardiography. We divided patients into the following3groups:A group, CRT echocardiographic response and clinical response group, the left ventricular end systolic volume was decreased≥15%from baseline to12-month follow-up, and namely the6minute walk test distance increased≥20%, or if that test was not performed, NYHA cardiac functional grading better≥1from baseline to12-month follow-up; B group, only CRT clinical response group from baseline to12-month follow-up; C group, CRT nonresponse group, neither meet the echocardiographic response standard, nor meet the clinical response standard at follow-up. The ratio of early diastolic mitral flow velocity and mitral annulus velocity and the (E/E’) was as a measure of left ventricular filling indicator. The following indices of LV diastolic function were obtained from2D speckle tracking echocardiography:early diastolic strain rate (LSRE, CSRE, RSRE and RotRE) and atrial contraction strain rate (LSRA, CSRA, RSRA and RotRA), UTR)VR, UTRE. Observe the differences of left ventricular diastolic function parameters between different degrees of response in cardiac resynchronization therapy. The correlation of diastolic function parameters obtained from2D-STE and E/E’ratio was analyzed. The receiver operating characteristic curve (receiver operating characteristic curve, ROC curve) of2D-STE derived parameters was analyzed to identify the predictive value for CRT echocardiographic response.Results:In70patients,41(58.6%) patients in the follow-up of12months was CRT echocardiographic and clinical responders;15(21.4%) patients for only clinical responders;14(20%) for the nonresponders. Most Parameters of evaluation left ventricular diastolic function were observed significant improved in the A group. Part of conventional parameters of diastolic function improved significantly in the B group. The gradual deterioration of E/E’was observed in the C group patients. Compare with other strain rate, SLRE had good correlated with E/E’(r=-0.778, P<0.01). But UTRIVRwas better correlated with E/E’(r=-0.837, P<0.01) than SLRE. By the ROC curve, UTRIvR predicted CRT echocardiographic response had maximum area under the ROC curve (0.822, p=0.032). The sensitivity of UTRIVR≥11.41for predicting CRT echocardiographic response was73%, and the specificity was75%.Conclusions:Diastolic strain rate of2D-STE and untwisting parameters can accurately assess the extent of response of CRT with different changes of diastolic function. The UTRIVR had better correlation of E/E’than the other parameters, and had greater value in prediction of CRT echocardiographic response, which could be used as more sensitive index to evaluation of diastolic function. Objective:In order to reduce the pacemaker lead related complications, researchers developed leadless pacemaker. The main advantages are that it can implanted percutaneous multiple positions, reduce infection and vascular obstruction and other complications. Our research compared the left ventricular global function of two group pigs using RT-3D STE technology, which were implanted with leadless pacemakers and commen pacemakers respectively; we sought to explore the feasibility of leadless pacemaker, and demonstrate the feasibility and effectiveness of RT-3D STE technology assessment of the left ventricular systolic function.Methods:The objects of our study were the Chinese Mini pigs (weight of45-55kg). The experimental group pigs were implanted2leadless pacemakers in right ventricular; control group pigs were implanted in commen pacemakers with2defibrillation leads in the right ventricular. The devices implanted intervals were4weeks. In the resting state, we used3D speckle tracking echocardiography to assessment global left ventricle strain of two group pigs. Global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS) and global radial strain (GRS) were calculated as percentages. At time flow-up, we measured leadless pacemaker performance (impedance and pacing threshold). When6months after implantation of two devices, the animals were sacrificed, we accurately measured the fiber adhesive lengths of each device and heart tissue was formed. At the same time, we verified feasibility and effectiveness of RT-3D STE technology assessment of the left ventricular function. In combination with the traditional left ventricular ejection fraction, the correlations of RT-3D STE derived parameters and left ventricular ejection fractions were analyzed.Results:Control and test pigs showed no statistically significant difference in GLS, GCS, GAS or GRS (p>0.05) before and after implantation. In two groups of pigs, before and after pacemaker working, there were no significant differences in each group and between two groups. After6months of follow-up, the measures of pacing performance (impedance and pacing threshold) were stably within the accepted range. During flow-up, the leadless pacemakers group had no complications such as infection; there was lcase (10%) of one lead dislocation in the commen pacemakers group. The three-dimensional strain RT-3D STE values are in good agreement with inter and intraobserver. The correlations between RT-3D STE and left ventricular EF value:in all the strain value parameters, the correlation between GAS and left ventricular ejection fraction was higher (r=0.914, P<0.01) than the others. Test pigs and controls showed statistically significant difference in the length of fibrosis along the device body (p< 0.05).Conclusions:It is suggested that a completely self-contained single-chamber leadless cardiac pacemaker has shown to be safe and feasible. The result can make it as alternative technology, especially for patients who with high risk of lead related complications. At the same time, this study tested the effectiveness of RT-3D STE technique to assess left ventricular systolic function, confirmed that GAS can be used as a reliable index for assessing except EF values.更多还原