Feasibility Study of Advanced Circulatory Support Devices that Enable Recovery and Optimal Therapy of Heart Failure in Pediatric and Adult Patients

本研究旨在设计和开发先进的循环支持装置，用于儿童和成人至少一个月的短期和中期不需要抗凝治疗，以允许完全恢复，或连接到更先进的治疗方式，如植入式装置或心脏移植。为了实现这一目标，利用紧凑的磁轴承设计了一种一次性磁悬浮离心血泵，其主要体积为23ml。采用X、Y两自由度主动磁轴承与永磁体被动恢复叶轮转子在轴向和倾斜轴上的位置相结合的方法实现了紧凑型磁轴承。叶轮的旋转是通过安装在电机轴上的内驱动磁铁与叶轮-转子内成型的从动磁铁之间的径向磁耦合实现的。在泵流量为5L/min，转速为4500rpm时，泵的最大扬程压力为800mmHg。溶血研究显示，对血细胞元素的机械损伤约为临床使用的BioPump BPX-80的一半。迄今为止，使用小牛进行的体内研究表明，该泵系统可以满足成人患者一周循环支持的要求，并且抗凝治疗的要求最低。在儿科应用方面，为3-10Kg的新生儿和婴儿设计了一种小型离心血泵TinyPump，主要容积为5ml，稳定的低流量控制能力为0.2L/min。叶轮转子的直径为30mm，带有六个直叶片，因此泵的外径为50mm。泵头是一次性的，很容易从可重复使用的电机驱动单元连接和分离。叶轮转子通过安装在电机轴上的6极外驱动磁体与叶轮-转子内成型的磁体之间的径向磁力耦合而旋转。叶轮-转子的中心由一个流体动力轴承支撑。叶轮-转子轴承间隙为150μm，通过轴承区域的二次流约为外部流量的10%。TinyPump在3Kg仔猪心肺旁路研究中的应用表明，与儿科BioPump BP-50相比，TinyPump的性能更优越。在单心室模型中，TinyPump也用于支持肺循环，显示肺循环稳定。TinyPump还被用作3.5公斤猪和10公斤柴巴山羊的左心室辅助装置，显示出稳定的低流量，非溶血性和生物相容性支持循环长达两周。本研究继续在1-2个月的时间里证明10Kg柴山羊的稳定和生物相容性。少

This study addresses design and development of advanced circulatory support devices intended for short and intermediate duration of at least one month without requiring anti-coagulation therapy in children and adults, for allowing complete recovery, or for bridging to more advanced treatment modalities such as implantable devices or heart transplantation.To achieve the goal, for adult applications a disposable, magnetically levitated (Mag-lev) centrifugal blood pump having a prime volume of 23ml was designed by utilizing a compact magnetic bearing. The compact magnetic bearing was implemented by combining two-degree-of freedom active magnetic bearing in X- and Y- directions with permanent magnets passively restoring the position of impeller rotor in the axial and tilting axes. The rotation of impeller was attained through radial magnetic coupling between the inner driver magnet mounted on the motor shaft and the follower magnet molded inside the impeller-rotor. The pump performance ana … More lysis showed the maximum head pressure of 800mmHg against the pump flow of 5L/min at the rotational speed of 4500rpm. The hemolysis study revealed that the mechanical damage to blood cell elements was about the half that of the clinically used BioPump BPX-80. To date in vivo study using calves has shown that the pump system can meet requirements for one-week circulatory support in adult patients with minimum requirement of anti-coagulation therapy.As for pediatric application, a miniature centrifugal blood pump TinyPump having prime volume of 5ml and stable low flow control capability to 0.2L/min has been designed for 3-10Kg neonates and infants. The diameter of the impeller rotor is 30mm with six straight vanes resulting in the external diameter of the pump to be 50mm. The pump head is disposable, and easily attached and detached from the re-usable motor driver unit. The impeller rotor is rotated by radial magnetic coupling force between the 6 pole external drive magnets mounted on the motor shaft and the magnets molded inside the impeller-rotor. The impeller-rotor is supported by a hydrodynamic bearing at its center. The gap clearance of 150μm in the bearing of the impeller-rotor resulted in the secondary flow through the bearing area to be about 10% of the external flow. The application of the TinyPump for heart-lung bypass studies in 3Kg piglets revealed superior performance in comparison against the pediatric BioPump BP-50. The TinyPump was also used to support lung circulation in the single ventricle model to show stable pulmonary circulation. The TinyPump has also been used as a left ventricular assist device in the 3.5Kg swine and 10Kg Shiba-goats, demonstrating stable low flow, non-hemolytic and biocompatible support of circulation to the period up to two weeks. The study continues to demonstrate the stable and biocompatible performance in 10Kg Shiba-goats for the duration of 1-2 months. Less