A Multi-Scale CFD-FSI Model of the Hybrid Norwood Palliative Treatment for Hypopl

描述（由申请人提供）：先天性心脏病发生在150个活产婴儿中的一个。左心发育不良综合征（HLHS）是最复杂的缺陷之一，发生在4%至5%的婴儿中。该提案重点关注新型混合诺伍德（HN）策略，该策略已成为新生儿HLHS的替代首次干预。HN是一种侵入性较小的手术，与传统方法相比具有许多手术优势，例如在新生儿期间避免心肺转流。我们的团队已经成功地开发了一个内部多尺度计算流体动力学（CFD）模型，以阐明所产生的复杂和远离直观的血流动力学应用于一个合成的几何代表的新生儿进行混合诺伍德姑息。具体目标-已经证明了我们的方法，这个初始的情况下，我们目前的重点是扩大和发展我们目前的模式，以解决以下具体目标：1。开发患者特定几何结构模拟，并确定动脉导管支架植入术近端不同程度的主动脉弓远端阻塞对冠状动脉、肺动脉和颈动脉血流的影响。2.探索患者特定的HN拓扑结构，以确定反向BT分流的最佳尺寸和可能位置，从而增加冠状动脉和颈动脉循环并减轻异常壁应力、停滞区和异常血流。3.开发一个HN拓扑案例，结合使用流体结构相互作用来研究血管超弹性顺应性对血液动力学和心室性能的影响。将目标1和2的结果与基于合成HN拓扑的先前计算进行比较，目标3的结果将为我们小组在最先进的心血管手术模拟中的未来研究铺平道路，最终将成为手术规划中的宝贵步骤。方法-建议利用HN循环的多尺度计算模型，实施患者特定MRI衍生几何结构，以解决特定目标中概述的关键问题。随后，血管和分流顺应性将被完全建模为“流体-结构相互作用”（FSI）：流场通过有限体积法求解，并提供应力载荷，导致顺应性血管壁的机械响应，将通过有限元法计算。顺应性通过血管和分流管的经验应力-应变关系来解释。顺应性容器的完整建模在之前的诺伍德循环的CFD研究中尚未考虑，这是所提出的工作的新奇。

DESCRIPTION (provided by applicant): Congenital heart disease occurs in one in 150 live births. Hypoplastic Left Heart Syndrome (HLHS), one of the most complex such defects, occurs in 4 to 5 percent of such infants. This proposal focuses on the novel Hybrid Norwood (HN) strategy which has emerged as an alternative first intervention for neonates with HLHS. The HN is a less invasive procedure that provides numerous surgical advantages over the conventional method, such as avoiding cardiopulmonary bypass during neonatal period. Our team has been successful in developing an in-house multi-scale computational fluid dynamics (CFD) model to elucidate the resulting complex and far from intuitive hemodynamics applied to a synthetic geometry representative of a neonate undergoing Hybrid Norwood palliation. Specific Aims - Having proven our methodology to this initial case our present focus is to expand and evolve our current model to address the following specific aims: 1. Develop a patient-specific geometry simulation and establish the effects on coronary, pulmonary, and carotid blood flow of various degrees of distal aortic arch obstruction proximal to the ductus arteriosus stenting. 2. Explore the patient-specific HN topologies to identify an optimal size and possible placement of the reverse BT shunt that provides an increase in coronary and carotid circulation and mitigates the abnormal wall stresses, stagnation zones, and anomalous flow. 3. Develop a HN topology case incorporating the use of Fluid Structure Interaction to study the effect of vascular hyper-elastic compliance on hemodynamics and ventricular performance. A comparison of results from aims 1 and 2 to previous computations based on a synthetic HN topology will be made and results from aim 3 will pave the way for the future research of our group in state-of-the-art cardiovascular procedure simulations that eventually will become an invaluable step in surgical planning. Methods - It is proposed to utilize a multi-scale computational model of the HN circulation with the implementation of a patient-specific MRI-derived geometry to address critical issues outlined in the specific aims. Subsequently, vascular and shunt compliance will be fully modeled as "fluid-structure interaction" (FSI): the flow field is resolved by the finite volume method and provides the stress loads that result in the mechanical response of the compliant vessel walls that will be calculated by the finite element method. Compliance is accounted for via empirical stress-strain relationship of the vessels and shunt. The full modeling of compliant vessels has not been accounted for in prior CFD studies of the Norwood circulation, and this is a novelty of the proposed work.