Clinic for Cardiac Surgery, University Hospital Zurich, Zurich, Switzerland.
Product Development Group Zurich, Department for Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland.
Biomed Tech (Berl). 2023 Apr 27;68(5):503-510. doi: 10.1515/bmt-2020-0188. Print 2023 Oct 26.
Left ventricular assist devices (LVADs) have been established as alternative to heart transplantation for patients with end-stage heart failure refractory to medical therapy. Right heart failure (RHF) after LVAD implantation is associated with inferior outcome. Its preoperative anticipation may influence the selection between a pure left ventricular and a biventricular device type and, thus, improve outcomes. Reliable algorithms to predict RHF are missing.
A numerical model was used for simulation of a cardiovascular circulation. The LVAD was placed as parallel circuit between left ventricle and aorta. In contrast to other studies, the dynamic hydraulic behavior of a pulsatile LVAD was replaced by that of a continuous LVAD. A variety of hemodynamic states was tested mimicking different right heart conditions. Adjustable parameters included heart rate (HR), pulmonary vascular resistance (PVR), tricuspid regurgitation (TR), right ventricular contractility (RVC) and pump speed. Outcome parameters comprised central venous pressure (CVP), mean pulmonary artery pressure (mPAP), cardiac output (CO) and occurrence of suction.
Alteration of HR, PVR, TR, RVC and pump speed resulted in diverse effects on CO, CVP and mPAP, resulting in improvement, impairment or no change of the circulation, depending on the degree of alteration.
The numerical simulation model allows prediction of circulatory changes and LVAD behaviour following variation of hemodynamic parameters. Such a prediction may be of particular advantage to anticipate RHF after LVAD implantation. It may help preoperatively to choose the appropriate strategy of only left ventricular or both left and right ventricular support.
左心室辅助装置（LVAD）已被确立为对药物治疗无效的晚期心力衰竭患者进行心脏移植的替代方法。LVAD 植入后出现右心衰竭（RHF）与预后不良相关。其术前预测可能会影响选择单纯左心室或双心室装置类型，从而改善预后。目前缺乏可靠的预测 RHF 的算法。
使用数值模型模拟心血管循环。LVAD 被放置在左心室和主动脉之间的并联电路中。与其他研究不同，脉动性 LVAD 的动态液压行为被连续性 LVAD 的行为所取代。通过模拟不同的右心条件，测试了各种血流动力学状态。可调参数包括心率（HR）、肺血管阻力（PVR）、三尖瓣反流（TR）、右心室收缩力（RVC）和泵速。结果参数包括中心静脉压（CVP）、平均肺动脉压（mPAP）、心输出量（CO）和抽吸的发生。
HR、PVR、TR、RVC 和泵速的改变对 CO、CVP 和 mPAP 产生了不同的影响，导致循环的改善、损害或无变化，具体取决于改变的程度。
数值模拟模型允许预测血流动力学参数变化后循环和 LVAD 行为的变化。这种预测对于预测 LVAD 植入后出现 RHF 可能特别有利。它可以帮助术前选择仅左心室或同时左、右心室支持的适当策略。
