Assessment of cardiac function during mechanical circulatory support: the quest for a suitable clinical index.
Assessment of cardiac function during mechanical circulatory support: the quest for a suitable clinical index.
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机械循环支持期间心脏功能的评估：寻求合适的临床指标。
DOI：
10.1109/iembs.2011.6090041
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Antaki,JamesF
中科院分区：
文献类型：
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作者：
Ferreira,AntonioL;Wang,Yajuan;Gorcsan3rd,John;Antaki,JamesF
提出了一个评价连续流左心室辅助装置（LVAD）植入患者左心室功能的新指标。从泵流量信号导出，该指数被定义为“假射血”分数（pEF）与泵排出的体积（单位：微摩尔）（Vd）之间的半对数关系的系数（k）。pEF定义为“伪每搏输出量”（pSV）与Vd的比值。伪每搏输出量是Vd与泵在收缩期排出的体积（Vs）之间的差，两者都是通过将泵流量相对于心动周期中的时间积分而获得的。在体内将k与其他两个指数：基于LV压力的指数MTP和基于泵流量的指数IQ进行比较。MTP是“三重乘积”与舒张末期压（EDP）之间线性回归的斜率。三重积TP = LV SP.dP/dtmax。HR是LV收缩压、LV压力的最大时间导数和心率的乘积。IQ是泵流量最大时间导数dQ/dtmax与泵流量峰间振幅变化QP 2 P之间线性回归的斜率。为了测试k对收缩状态变化的反应，通过药物干预改变收缩性。k的绝对值从1.354±0.25（基线）降至艾司洛尔输注后的0.685±0.21。该指标对变力状态的变化敏感，有可能用于临床评估植入VAD的患者的收缩功能。
A new index to assess left ventricular (LV) function in patients implanted with continuous flow left-ventricular assist devices (LVADs) is proposed. Derived from the pump flow signal, this index is defined as the coefficient (k) of the semiloga-rithmic relationship between “pseudo-ejection” fraction (pEF) and the volume discharged by the pump in diastole, (V d). pEF is defined as the ratio of the “pseudo-stroke volume” (pSV) to V d. The pseudo-stroke volume is the difference between V d and the volume discharged by the pump in systole (V s), both obtained by integrating pump flow with respect to time in a cardiac cycle. k was compared in-vivo with others two indices: the LV pressure-based index, MTP, and the pump flow-based index, IQ. MTPis the slope of the linear regression between the “triple-product” and end-diastolic pressure, EDP. The triple-product, TP = LV SP.dP/dtmax. HR, is the product of LV systolic pressure, maximum time-derivative of LV pressure, and heart rate. IQis the slope of the linear regression between maximum time-derivative of pump flow, dQ/dtmax, and pump flow peak-to-peak amplitude variation, QP2P. To test the response of k to contractile state changes, contractility was altered through pharmacological interventions. The absolute value of k decreased from 1.354±0.25 (baseline) to 0.685±0.21 after esmolol infusion. The proposed index is sensitive to changes in inotropic state, and has the potential to be used clinically to assess contractile function of patients implanted with VAD.