Department of Cardiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
Cardiovascular Imaging and Dynamics Lab, KU Leuven, Leuven, Belgium.
Sci Rep. 2023 Oct 17;13(1):17660. doi: 10.1038/s41598-023-44588-4.
Ultrasound-based shear wave elastography is a promising technique to non-invasively assess the dynamic stiffness variations of the heart. The technique is based on tracking the propagation of acoustically induced shear waves in the myocardium of which the propagation speed is linked to tissue stiffness. This measurement is repeated multiple times across the cardiac cycle to assess the natural variations in wave propagation speed. The interpretation of these measurements remains however complex, as factors such as loading and contractility affect wave propagation. We therefore applied transthoracic shear wave elastography in 13 pigs to investigate the dependencies of wave speed on pressure-volume derived indices of loading, myocardial stiffness, and contractility, while altering loading and inducing myocardial ischemia/reperfusion injury. Our results show that diastolic wave speed correlates to a pressure-volume derived index of operational myocardial stiffness (R = 0.75, p < 0.001), suggesting that both loading and intrinsic properties can affect diastolic wave speed. Additionally, the wave speed ratio, i.e. the ratio of systolic and diastolic speed, correlates to a pressure-volume derived index of contractility, i.e. preload-recruitable stroke work (R = 0.67, p < 0.001). Measuring wave speed ratio might thus provide a non-invasive index of contractility during ischemia/reperfusion injury.
基于超声的剪切波弹性成像是一种有前途的技术，可以非侵入性地评估心脏的动态刚度变化。该技术基于跟踪在心肌中传播的声激发剪切波，其传播速度与组织刚度相关。该测量在整个心动周期中重复多次，以评估波传播速度的自然变化。然而，这些测量的解释仍然很复杂，因为诸如负荷和收缩性等因素会影响波的传播。因此，我们在 13 头猪中应用了经胸剪切波弹性成像，以研究波速与压力-容积衍生的负荷、心肌僵硬和收缩性指数之间的依赖性，同时改变负荷并诱导心肌缺血/再灌注损伤。我们的结果表明，舒张波速与压力-容积衍生的操作心肌僵硬指数相关（R=0.75，p<0.001），表明负荷和内在特性都可以影响舒张波速。此外，波速比，即收缩波速和舒张波速的比值，与压力-容积衍生的收缩性指数，即预负荷可募集的做功（R=0.67，p<0.001）相关。因此，测量波速比可能在缺血/再灌注损伤期间提供一种非侵入性的收缩性指数。
