Development of a Fully-Implantable Ventricular Assist Device for Neonates and Children with Heart Failure - with Magnetic Levitation to Improve Hemocompatibility

项目摘要 先天性心脏病（CHD）导致的儿童心力衰竭的年发病率为每1000人中有1至2例 出生在美国，每年有10,000到14,000名儿童住院等待新的心脏， 2016年仅进行了444例移植手术，说明捐赠心脏严重短缺。唯一长- 替代心脏移植的一种治疗方法是植入心室辅助装置（VAD），一种泵 帮助衰竭的心脏泵血，直到有新的心脏可用。然而，这些VAD太大， 可完全植入4岁以下儿童体内;因此，这些VAD放置在外部， 腹部，有管子穿过皮肤。这些管子会导致感染， 在泵支持期间（可能超过1年）离开医院。此外，生存 体重小于5 kg的患者使用目前可用的VAD的比例令人沮丧;超过60%的患者 儿童在VAD植入后死亡，中风是最常见的死亡原因。因此需要 设计一种更安全、完全植入式的小儿VAD，以提高婴幼儿的生存率。这 VAD还需要随着儿童的生长发育而调整，这意味着它必须提供更高的 随着孩子的成长，血液流动和压力。这项研究的目的是开发第一个完全植入式 VAD（NeoVAD）用于婴儿和幼儿，这将有助于衰竭的心脏，直到找到合适的供体心脏。 available.在目标1中，开发微型磁悬浮系统以消除机械磨损， 优化泵的性能，这将提供长期的循环支持。的 不同生理操作下NeoVAD在稳态流动环境中的血流动力学性能 将在目标2中研究这些问题。最后，在目标3中，全身血液相容性和血流动力学 NeoVAD的性能将通过体外和大动物研究进行评价。这个泵在植入后 可以让儿童心力衰竭患者在医院外恢复正常生活。 这项研究将为设计一种可以支持衰竭心脏的泵提供新的见解， 患者，从婴儿到体重不超过20公斤的儿童。这种广泛的支持将消除 随着孩子的成长，更换VAD或接受多次心脏移植，这两种手术都是有风险的。还有， 这项研究将包括对泵血相互作用的深入研究， 研究随着儿童的成长，血流速度和压力的变化如何影响血液切应力。这 这项研究将使我们能够为幼儿设计第一个安全的、完全植入式VAD， 降低中风、出血和感染的风险，提高生存机会。我们预计 通过植入NeoVAD，儿童CHD患者可以在医院外过上接近正常的生活， 对他们的生活质量会有很大的改善。

PROJECT SUMMARY The annual incidence of pediatric heart failure due to congenital heart disease (CHD) is 1 to 2 cases per 1000 births. Whereas 10,000 to 14,000 children are hospitalized annually in the United States waiting for a new heart, only 444 transplants were performed in 2016, illustrating the drastic shortage of donor hearts. The only long- term treatment alternative to a heart transplant is the implantation of a ventricular assist device (VAD), a pump that helps the failing heart to pump blood until a new heart is available. However, these VADs are too large to be fully implantable in children under 4 years of age; therefore, these VADs are placed externally near the abdomen, with tubes running through the skin. These tubes can lead to infection, and they prevent the children from leaving the hospital for the duration of pump support, which can exceed 1 year. Additionally, the survival rate of patients weighing less than 5 kg with the currently available VADs is dismal; more than 60% of these children die after VAD implantation, stroke being the most common cause of death. Therefore, there is a need to design a safer, fully implantable pediatric VAD to improve the survival of both infants and young children. This VAD also needs to be adjustable with the child’s growth and development, meaning that it must provide higher blood flow and pressure as the child grows. The objective of this study is to develop the first fully implantable VAD (NeoVAD) for infants and young children, which would help the failing heart until a suitable donor heart is available. In Aim 1, development of a miniature magnetic levitation system to eliminate mechanical wear and optimize the pump performance is proposed, which will provide a long-term circulatory support. The hemodynamic performance of the NeoVAD in steady-state flow environments at different physiological operating points will be investigated in Aim 2. Finally, in Aim 3, systemic hemocompatibility and hemodynamic performance of the NeoVAD will be evaluated by in vitro and large-animal studies. This pump, after implantation, would allow pediatric heart failure patients to return to a near-normal life outside the hospital. This research will give new insights into designing a pump that can support the failing heart for a wide range of patients, from infants to children weighing up to 20 kg. This wide range of support would eliminate the need to change VADs or undergo multiple heart transplants as the child grows, both of which are risky procedures. Also, this research will include an in-depth study of pump-blood interaction across the patient age range, allowing us to study how blood shear stress is affected by changes in blood flow rate and pressure as the child grows. This study will enable us to design the first safe, fully implantable VAD for young children, which would reduce the risk of stroke, bleeding, and infection and improve their chances of survival. We expect that with the implanted NeoVAD, pediatric CHD patients can live a near-normal life outside the hospital, which would be a significant improvement in their quality of life.