University of Rochester Medical Center, Rochester, New York 14642, USA.
J Am Soc Echocardiogr. 2010 Mar;23(3):324-9. doi: 10.1016/j.echo.2009.12.005.
Many implantable ventricular assist devices (VADs) have no direct measurement of pump output. The aim of this study was to test the hypothesis that quantitative contrast echocardiography can be used to measure VAD output.
Contrast-enhanced Doppler velocity-time integral (VTI) was measured in the VAD inlet and outlet cannulae. Doppler flow (Doppler Q=Doppler VTIxcannula area) was compared with measured flow (Q). A total of 130 flow measurements were made (at 6400 and 12,000 rpm).
Doppler Q in the outflow and inflow cannulae showed an excellent correlation with measured Q (outlet Doppler Q=1.0052 xQ+0.048, R2=0.9865; inlet Doppler Q=1.5043 xQ+0.003, R2=0.9904), but inlet Doppler Q was 50% higher. Correcting for the flow profile of the conical inlet tube yielded excellent correlation (inlet Doppler Q=1.0029 xQ+0.002, R2=0.9904).
Noninvasive Doppler flow techniques can be used to accurately measure VAD flow, but the flow profile in the cannula needs to be taken into account.
许多植入式心室辅助装置（VAD）无法直接测量泵输出量。本研究旨在验证定量对比超声心动图可用于测量 VAD 输出量的假设。
在 VAD 入口和出口套管中测量对比增强的多普勒速度时间积分（VTI）。多普勒流量（Doppler Q=Doppler VTIxcannula 面积）与测量的流量（Q）进行比较。共进行了 130 次流量测量（在 6400 和 12000rpm 下进行）。
流出道和流入道套管中的多普勒 Q 与测量的 Q 呈极好的相关性（流出道多普勒 Q=1.0052xQ+0.048，R2=0.9865；流入道多普勒 Q=1.5043xQ+0.003，R2=0.9904），但流入道多普勒 Q 高 50%。校正锥形入口管的流量分布后，相关性良好（流入道多普勒 Q=1.0029xQ+0.002，R2=0.9904）。
非侵入性多普勒流量技术可用于准确测量 VAD 流量，但需要考虑套管中的流量分布。
