Preload Sensitivity with TORVAD Counterpulse Support Prevents Suction and Overpumping.
Preload Sensitivity with TORVAD Counterpulse Support Prevents Suction and Overpumping.
复制标题
TORVAD 反脉冲支持的预载灵敏度可防止吸力和过度泵送。
DOI：
10.1007/s13239-019-00419-0
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发表时间：
2019
影响因子：
1.8
通讯作者：
Smalling,RichardW
中科院分区：
文献类型：
--
作者：
Gohean,JeffreyR;Larson,ErikR;Longoria,RaulG;Kurusz,Mark;Smalling,RichardW
目的：本研究比较了连续流（CF） VAD支架与Windmill环形VAD （TORVAD）反脉动的预载灵敏度。TORVAD是一种双活塞旋转泵，在舒张早期喷射30ml，在保持主动脉瓣血流的同时增加心输出量。方法采用两种心血管系统集总参数模型，比较CF和TORVAD反搏支持的spreload敏感性：(1)采用体循环开环模型，分离体循环，规定负荷前和负荷后边界条件，得到心室功能曲线；(2)采用闭环模型，测试肺血管阻力、全身血管阻力、心率、肌力状态和血容量变化的生理反应。在开环模型中，心室功能曲线（心输出量vs左心室预负荷）用于评估预负荷敏感性。在闭环模型中，采用左室收缩末期容积评估左室吸力风险。结果在5 mmHg的低预负荷下，CF支架与TORVAD反脉冲支架相比，循环过度（健康心脏的心输出量为3.3 L/min， CF支架为4.7 L/min， TORVAD反脉冲支架为3.5 L/min），且灵敏度远低于反脉冲支架（健康心脏0.342 L/min/mmHg， CF支架为0.092 L/min， TORVAD反脉冲支架为0.306 L/min）。在闭环模型中，当PVR升高超过0.035 mmHg s/mL时，CF支持使循环过泵，引起心室吸力事件，而TORVAD反脉支持维持足够的心室容积，不引起吸力。结论TORVAD的反脉冲支撑保留了主动脉瓣血流，并在所有预负荷条件下提供了生理敏感性。这样可以防止过度抽吸，并将吸入的风险降到最低。
PurposeThis study compares preload sensitivity of continuous flow (CF) VAD support to counterpulsation using the Windmill toroidal VAD (TORVAD). The TORVAD is a two-piston rotary pump that ejects 30 mL in early diastole, which increases cardiac output while preserving aortic valve flow.MethodsPreload sensitivity was compared for CF vs. TORVAD counterpulse support using two lumped parameter models of the cardiovascular system: (1) an open-loop model of the systemic circulation was used to obtain ventricular function curves by isolating the systemic circulation and prescribing preload and afterload boundary conditions, and (2) a closed-loop model was used to test the physiological response to changes in pulmonary vascular resistance, systemic vascular resistance, heart rate, inotropic state, and blood volume. In the open-loop model, ventricular function curves (cardiac output vs left ventricular preload) are used to assess preload sensitivity. In the closed-loop model, left ventricular end systolic volume is used to assess the risk of left ventricular suction.ResultsAt low preloads of 5 mmHg, CF support overpumps the circulation compared to TORVAD counterpulse support (cardiac output of 3.3 L/min for the healthy heart, 4.7 with CF support, and 3.5 with TORVAD counterpulse support) and has much less sensitivity than counterpulse support (0.342 L/min/mmHg for the healthy heart, 0.092 with CF support, and 0.306 with TORVAD counterpulse support). In the closed-loop model, when PVR is increased beyond 0.035 mmHg s/mL, CF support overpumps the circulation and causes ventricular suction events, but TORVAD counterpulse support maintains sufficient ventricular volume and does not cause suction.ConclusionsCounterpulse support with the TORVAD preserves aortic valve flow and provides physiological sensitivity across all preload conditions. This should prevent overpumping and minimize the risk of suction.