This article investigates a specific type of cardiac assist device, its functional performance, and its effects on the hemodynamic patterns of blood flow through the aortic network. The aforementioned assist device can be implanted in a given patient suffering from left ventricular failure. Our previous study focused on multi-balloons device. The current cardiac assist device is composed of two semi-cylindrical double-layer balloons surrounding the ascending aorta, thereby increasing the force with which blood will be pumped into the circulatory system with its inflation and deflation mechanism. The inflation and deflation of the balloon take place during the diastolic and systolic phases of the heart, respectively, by pumping and suctioning a specific gas coming from a micropump into or out of the space between the two layers of the balloons. A three-dimensional model of the aortic network assisted by the cardiac device is constructed based on the patient’s individual anatomical and physiological conditions and simulated within two complete cardiac cycles using the fluid–structure interaction analysis. The simulation is performed using the assumptions of linear elastic materials for the balloon and the aorta, and Newtonian and incompressible fluid for the blood. Result shows that the maximum outflow of the descending aorta increases by 20 ml/s and 10 ml/s in the brachiocephalic artery at time 0.4 s (maximum inflation). This increase is equal to 5 ml/s in the carotid and subclavian arteries. During the time period of 0.4–0.5 s (constant applied pressure), the balloon has no considerable movement. The outflow experiences a nearly uniform flow with slight oscillations within this interval in the presence of the assist device. The net energy of the blood flow is decreased if the Young’s modulus of the balloon part of the assist device increases. Furthermore, the stress generated at the outer curvature of the aorta is higher than that of inner curvature in case of using cardiac assist device. This study demonstrates the relevance of the three-dimensional model in clinical practice. Such simulation can provide clinicians and surgeons with relevant information in order to select the most patient-centered and clinically appropriate cardiac assist device addressing the pathological conditions of a specific patient. Furthermore, this study can be a source of comparison with the previous study on multi-balloons device.

中文翻译：

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用于左心室衰竭的特定类型心脏辅助装置的生物力学、结构和性能分析

本文研究了一种特定类型的心脏辅助装置、其功能性能及其对通过主动脉网络的血流血流动力学模式的影响。前述辅助装置可植入患有左心室衰竭的给定患者。我们之前的研究集中在多气球设备上。当前的心脏辅助装置由围绕升主动脉的两个半圆柱形双层球囊组成，从而通过其膨胀和收缩机制增加将血液泵入循环系统的力。通过将来自微型泵的特定气体泵入或抽出两层气球之间的空间，气球的膨胀和收缩分别在心脏的舒张期和收缩期发生。基于患者的个体解剖和生理条件构建由心脏装置辅助的主动脉网络的三维模型，并使用流固耦合分析在两个完整的心动周期内进行模拟。使用球囊和主动脉的线弹性材料以及血液的牛顿流体和不可压缩流体的假设来执行模拟。结果显示降主动脉的最大流出量在​​0.4 s（最大膨胀）时在头臂动脉中增加了20 ml / s和10 ml / s。这种增加在颈动脉和锁骨下动脉中等于 5 ml/s。在 0.4-0.5 秒（恒定施加压力）的时间段内，气球没有明显的运动。在辅助装置存在的情况下，流出物在该间隔内经历几乎均匀的流动，并带有轻微的振荡。如果辅助装置的球囊部分的杨氏模量增加，则血流的净能量减少。此外，在使用心脏辅助装置的情况下，主动脉外曲率处产生的应力高于内曲率处的应力。本研究证明了三维模型在临床实践中的相关性。这种模拟可以为临床医生和外科医生提供相关信息，以便选择最以患者为中心和临床上最合适的心脏辅助设备，以解决特定患者的病理状况。此外，这项研究可以作为与先前关于多气球装置的研究进行比较的来源。