Analysis of the Pediatric Heart Network Echocardiogram Database to Establish Left Ventricular Strain Z-scores

项目总结 在儿童中，使用超声心动图(ECHO)计算射血(EF)和短轴缩短率(SF)是 评价左心室(LV)功能的护理标准。尽管EF和SF的使用无处不在，但它们的表现很差 可重复性的，从多个测量计算，每个测量都有它们自己的传播误差，以及 测量心内膜容量变化，而不直接测量收缩能力。变形应变为 从根本上不同于EF和SF。Echo软件技术不是测量音量，而是提供 斑点追踪心肌运动以测量局部和整体心肌变形以获得LV 紧张。由于这个过程是自动化的，它在很大程度上消除了对观察者的依赖。此外，由于 应变是单次测量，而不是从多个测量计算的派生参数， 机器派生应变的误差应该大大减少。LV毒株在成人中得到了广泛的研究 其中正常的参考范围得到验证，并用于预测临床结果和改进治疗。在……里面 相比之下，基于大量不同儿童人口的LV菌株参考值是不可用的，并且 在儿科人群中，菌株在很大程度上仍然是一种研究工具。为了解决这个问题，我们将建立Z-Score 使用PHN Echo数据库。该数据库包含测量LV应变所需的所有图像 在一组年龄从出生到18岁的健康儿童中获得了3526个回声 好几年了。Z分数通过考虑身体尺寸、年龄、性别和/或来考虑成熟和成长的影响 在评估测量结果是否正常时竞相进行，或者如果不正常，它们的标准偏差有多少 偏离平均数。建立Z分数是归一化最有效和最灵活的方法 心血管参数的年龄和体型的影响，并已成为 儿科心脏病学。我们将确定独立的参数，如年龄，身高，体重，体表 面积或心率可以预测LV应变随成熟和/或生长的变化。为了指导临床使用，我们将 确定常规采集图像的LV应变测量的可行性和重复性 临床护理，而不是作为严格研究方案的一部分。我们将对抽样的效果进行评估 通过比较≥30帧/心跳与30帧/心跳的Z分数在临床指示研究中的频率 每个年龄段。这个项目意义重大，几乎将影响到每个儿科专科。LV LV-Z评分将使纵向研究能够确定LV-Score是否比EF更能预测预后 或儿童中的SF。如果是这样的话，菌株将进入临床使用，并导致评估和 对儿童有左心功能不全和随后的心力衰竭风险的疾病的管理。PHN 作为常规临床护理获得的正常回声图像数据库，这些图像来自一大群特征良好的 健康的儿童提供了一个独特的、经济有效的机会来建立正常的LV株Z分数并迅速 将它们部署在忙碌的儿科回声实验室的真实环境中使用。

PROJECT SUMMARY In children, calculating ejection (EF) and shortening fraction (SF) using echocardiography (echo) is the standard of care for evaluating left ventricular (LV) function. Despite their ubiquitous use, EF and SF are poorly reproducible, calculated from multiple measurements each with their own error that is propagated, and measure endocardial volume change without directly measuring contractility. Deformation strain is fundamentally different from EF and SF. Instead of measuring volumes, echo software technology provides speckle-tracking of myocardial movement to measure regional and global myocardial deformation to obtain LV strain. Since this process is automated, it removes a large degree of observer-dependence. In addition, since strain is a single measurement rather than a derived parameter calculated from multiple measurements, the error for machine-derived strain should be substantially reduced. LV strain has been widely studied in adults where normal reference ranges are validated and it is used to predict clinical outcomes and refine therapies. In contrast, LV strain reference values based on a large, diverse population of children are not available and strain remains largely a research tool in the pediatric population. To address this, we will establish Z-scores using the PHN Echo Database. This database includes all images needed for LV strain measurements from 3526 echoes obtained in a well-characterized population of healthy children ranging in age from birth to 18 years. Z-scores account for the effects of maturation and growth by considering body size, age, gender, and/or race when evaluating whether measurements are normal or, if abnormal, how many standard deviations they deviate from the mean. Establishing Z-scores is the most powerful and flexible approach to normalizing cardiovascular parameters for the effects of age and body size and has become the standard approach in pediatric cardiology. We will determine if independent parameters such as age, height, weight, body surface area, or heart rate can predict changes in LV strain with maturation and/or growth. To guide clinical use, we will determine the feasibility and reproducibility of LV strain measurements for images collected as part of routine clinical care rather than as part of a rigorous research protocol. We will evaluate the effect of sampling frequency on Z-scores for clinically indicated studies by comparing those with ≥30 vs. <30 frames/heartbeat in each age category. This project is highly significant and will impact nearly every pediatric subspecialty. LV strain Z-scores will enable longitudinal studies to determine if LV strain is more predictive of outcomes than EF or SF in children. If so, strain would move into clinical use and lead to a paradigm shift in the evaluation and management of diseases where the child is at risk for LV dysfunction and subsequent heart failure. The PHN database of normal echo images obtained as routine clinical care from a large, well-characterized population of healthy children provides a unique, cost-effective opportunity to establish normal LV strain Z-scores and rapidly deploy them for use in the real world setting of a busy pediatric echo lab.