Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.
Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.
J Am Soc Echocardiogr. 2019 Aug;32(8):958-968.e4. doi: 10.1016/j.echo.2019.04.418. Epub 2019 Jun 21.
The aim of this study was to test the hypothesis that intrinsic cardiac elastography can detect diastolic tissue abnormalities produced by cardiac amyloid infiltration and that measurements may have incremental value beyond traditional echocardiographic measures. The specific aims were (1) to evaluate the relationship between left ventricular myocardial stiffness (by elastography) and measures of diastolic chamber stiffness and systolic strain in patients with amyloidosis and (2) to compare their prognostic potential.
We prospectively studied 67 patients with amyloidosis (cardiac amyloidosis, n = 48; noncardiac amyloidosis, n = 19) and 40 normal subjects. Patients underwent comprehensive echocardiography including measurement of left ventricular global longitudinal strain (GLS) by speckle-tracking. Intrinsic velocity propagation of myocardial stretch (iVP), a direct measure of myocardial elasticity, was quantified using intrinsic cardiac elastography. Chamber stiffness was evaluated from the end-diastolic pressure-volume relationships (P = αV). The major end point at follow-up was the composite of death, cardiac hospitalization, worsening heart failure, and stroke.
The iVP of myocardial stretch was highest in patients with cardiac amyloidosis compared with those with noncardiac amyloidosis and normal subjects (3.2 ± 1.0, 1.8 ± 0.4, and 1.6 ± 0.2 m/sec, respectively; P < .0001) and correlated with chamber stiffness, function, and structure (β coefficient, operating chamber stiffness, GLS, wall thickness; P ≤ .001 for all). At follow-up (median, 2.6 years), measures of left ventricular and myocardial stiffness, GLS, diastolic dysfunction grade, and N-terminal pro-brain natriuretic peptide were associated with excess events. At multivariate analysis, iVP of myocardial stretch remained an independent predictor of adverse events, incremental to GLS and N-terminal pro-brain natriuretic peptide.
Measurements by cardiac elastography correlate with functional and structural derangements produced by cardiac amyloid infiltration but provide unique information that is incremental to conventional echocardiography.
本研究旨在验证内在心脏弹性成像能够检测到心肌淀粉样变性浸润引起的舒张组织异常的假设，并验证该检测手段的测量值是否具有比传统超声心动图测量值更大的附加价值。具体目标是：（1）评估心肌僵硬（弹性成像）与淀粉样变性患者舒张室僵硬和收缩应变的测量值之间的关系；（2）比较其预后价值。
我们前瞻性研究了 67 名淀粉样变性患者（心脏淀粉样变性，n=48；非心脏淀粉样变性，n=19）和 40 名正常对照者。患者接受了全面的超声心动图检查，包括斑点追踪法测量左心室整体纵向应变（GLS）。使用内在心脏弹性成像技术量化心肌拉伸的固有速度传播（iVP），这是心肌弹性的直接测量值。从舒张末期压力-容积关系（P=αV）评估腔室僵硬。随访的主要终点是死亡、心脏住院、心力衰竭恶化和中风的复合终点。
与非心脏淀粉样变性患者和正常对照者相比，心脏淀粉样变性患者的心肌拉伸 iVP 最高（分别为 3.2±1.0、1.8±0.4 和 1.6±0.2m/sec；P<0.0001），并且与腔室僵硬、功能和结构相关（β系数、工作腔室僵硬、GLS、壁厚度；所有 P 值均≤0.001）。在随访期间（中位数为 2.6 年），左心室和心肌僵硬、GLS、舒张功能分级和 N 末端脑钠肽前体的测量值与不良事件相关。多变量分析显示，心肌拉伸 iVP 仍然是不良事件的独立预测因子，与 GLS 和 N 末端脑钠肽前体相比具有附加价值。
心脏弹性成像的测量值与心肌淀粉样变性浸润引起的功能和结构障碍相关，但提供了比传统超声心动图更独特的信息。
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