Control of ventricular unloading using an electrocardiogram-synchronized Thoratec paracorporeal ventricular assist device.
Control of ventricular unloading using an electrocardiogram-synchronized Thoratec paracorporeal ventricular assist device.
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DOI：
10.1016/j.jtcvs.2012.12.048
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发表时间：
2013-09
期刊：
影响因子：
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通讯作者：
Raffael Amacher;A. Weber;H. Brinks;S. Axiak;Antonio L. Ferreira;L. Guzzella;T. Carrel;J. Antaki;S. Vandenberghe
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文献类型：
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作者：
Raffael Amacher;A. Weber;H. Brinks;S. Axiak;Antonio L. Ferreira;L. Guzzella;T. Carrel;J. Antaki;S. Vandenberghe
目的由于心电触发模式已被摒弃，目前的脉动辅助装置以固定频率或充盈到空的模式与左心室非同步工作。我们假设，在同步模式下改变射血延迟可以更精确地控制血流动力学和左心室负荷。方法8只绵羊通过脑室-主动脉插管接受了Thoratec准心脏辅助心脏辅助装置(Thoratec公司，Pleasanton，加利福尼亚州)。记录左心室压力和容量、主动脉压力、肺流量、泵腔压力、泵的流入和流出。该泵由临床气动驱动装置(Medos MedizinTechnik AG，Stolberg，德国)与本地R波同步驱动。泵射血开始时间在心动周期的0%至100%之间延迟10%。对每一个延迟，血流动力学变量与基线数据进行配对测试。结果观察到最小每搏做功的位置延迟10%(主动脉瓣开放后不久)，导致每搏做功与基线相比中位数减少43%。最大每搏功出现在中位延迟70%，中位每搏功比基线增加11%。以舒张末容量表示的左心室容量卸载在交配时最为明显(延迟为0%)。结论同步模式下的泵射血时机可控制左心室能量，可作为一种逐步恢复左心室负荷的方法。当需要最大限度的卸载时，传统上建议的反搏在脑室-主动脉插管中并不是最理想的。
ObjectiveCurrent pulsatile ventricular assist devices operate asynchronous with the left ventricle in fixed-rate or fill-to-empty modes because electrocardiogram-triggered modes have been abandoned. We hypothesize that varying the ejection delay in the synchronized mode yields more precise control of hemodynamics and left ventricular loading. This allows for a refined management that may be clinically beneficial.MethodsEight sheep received a Thoratec paracorporeal ventricular assist device (Thoratec Corp, Pleasanton, Calif) via ventriculo-aortic cannulation. Left ventricular pressure and volume, aortic pressure, pulmonary flow, pump chamber pressure, and pump inflow and outflow were recorded. The pump was driven by a clinical pneumatic drive unit (Medos Medizintechnik AG, Stolberg, Germany) synchronously with the native R-wave. The start of pump ejection was delayed between 0% and 100% of the cardiac period in 10% increments. For each of these delays, hemodynamic variables were compared with baseline data using pairedttests.ResultsThe location of the minimum of stroke work was observed at a delay of 10% (soon after aortic valve opening), resulting in a median of 43% reduction in stroke work compared with baseline. Maximum stroke work occurred at a median delay of 70% with a median stroke work increase of 11% above baseline. Left ventricular volume unloading expressed by end-diastolic volume was most pronounced for copulsation (delay 0%).ConclusionsThe timing of pump ejection in synchronized mode yields control over left ventricular energetics and can be a method to achieve gradual reloading of a recoverable left ventricle. The traditionally suggested counterpulsation is not optimal in ventriculo-aortic cannulation when maximum unloading is desired.