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首页> 美国卫生研究院文献>other >Non-Invasive Determination of Left Ventricular Workload in Patients with Aortic Stenosis Using Magnetic Resonance Imaging and Doppler Echocardiography
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Non-Invasive Determination of Left Ventricular Workload in Patients with Aortic Stenosis Using Magnetic Resonance Imaging and Doppler Echocardiography

机译：磁共振成像和多普勒超声心动图无创确定主动脉瓣狭窄患者左室工作量

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Early detection and accurate estimation of aortic stenosis (AS) severity are the most important predictors of successful long-term outcomes in patients. Current clinical parameters used for evaluation of the AS severity have several limitations including flow dependency. Estimation of AS severity is specifically challenging in patients with low-flow and low transvalvular pressure gradient conditions. A proper diagnosis in these patients needs a comprehensive evaluation of the left ventricle (LV) hemodynamic loads. This study has two objectives: (1) developing a lumped-parameter model to describe the ventricular-valvular-arterial interaction and to estimate the LV stroke work (SW); (2) introducing and validating a new index, the normalized stroke work (N-SW), to assess the global hemodynamic load imposed on the LV. N-SW represents the global hemodynamic load that the LV faces for each unit volume of blood ejected. The model uses a limited number of parameters which all can be measured non-invasively using current clinical imaging modalities. The model was first validated by comparing its calculated flow waveforms with the ones measured using Cardiovascular Magnetic Resonance (CMR) in 49 patients and 8 controls. A very good correlation and concordance were found throughout the cycle (median root mean square: 12.21 mL/s) and between the peak values (r = 0.98; SEE = 0.001, p<0.001). The model was then used to determine SW using the parameters measured with transthoracic Doppler-echocardiography (TTE) and CMR. N-SW showed very good correlations with a previously-validated index of global hemodynamic load, the valvular arterial impedance (), using data from both imaging modalities (TTE: r = 0.82, SEE = 0.01, p<0.001; CMR: r = 0.74, SEE = 0.01, p<0.001). Furthermore, unlike , N-SW was almost independent from variations in the flow rate. This study suggests that considering N-SW may provide incremental diagnostic and prognostic information, beyond what standard indices of stenosis severity and provide, particularly in patients with low LV outflow.
机译：早期发现和准确评估主动脉瓣狭窄（AS）的严重程度是患者成功取得长期预后的最重要指标。用于评估AS严重性的当前临床参数具有多个限制，包括血流依赖性。对于低流量和低经瓣膜压力梯度情况的患者，AS严重性的估计尤其具有挑战性。这些患者的正确诊断需要对左心室（LV）血流动力学负荷的全面评估。这项研究有两个目标：（1）建立一个集总参数模型来描述心室-瓣膜-动脉相互作用并评估左室卒中功（SW）； （2）引入并验证一个新指标，即标准化卒中工作（N-SW），以评估施加在LV上的总体血液动力学负荷。 N-SW代表LV所喷射的每单位血液量所面对的总体血液动力学负荷。该模型使用有限数量的参数，所有这些参数都可以使用当前的临床成像模式进行非侵入式测量。该模型首先通过将其计算的流量波形与使用心血管磁共振（CMR）测量的流量波形进行比较来验证，该模型在49位患者和8位对照中得到了验证。在整个循环中（均方根中位数：12.21 mL / s）以及在峰值之间（r = 0.98； SEE = 0.001，p <0.001），发现了很好的相关性和一致性。然后使用该模型通过经胸多普勒超声心动图（TTE）和CMR测量的参数确定SW。使用两种成像方式的数据，N-SW与先前验证的总体血流动力学负荷指数，即瓣膜动脉阻抗（）均显示出非常良好的相关性（TTE：r = 0.82，SEE = 0.01，p <0.001； CMR：r = 0.74，SEE ＝ 0.01，p ＜0.001）。此外，与N-SW不同，N-SW几乎不受流量变化的影响。这项研究表明，考虑N-SW可能会提供更多的诊断和预后信息，超过狭窄严重程度所能提供的标准指标，尤其是对于左室流出量低的患者。

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