Computational Modeling of Mechanical Heart Valves

机械心脏瓣膜的计算模型

• 批准号: 7060016
• 负责人: AJIT P YOGANATHAN
• 金额: $ 31.99万
• 依托单位: GEORGIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7060016
• 关键词: computer program /software; computer simulation; data collection methodology /evaluation; erythrocytes; hemodynamics; hemolysis; heterodyning; mathematical model; method development; model design /development; platelet activation; prosthetic heart valve; shear stress; thromboembolism

DESCRIPTION (provided by applicant): Present-day designs of mechanical prosthetic heart valves (MPHV) are far from ideal and significant complications such as hemolysis, platelet destruction, and thromboembolism-often arise after their implantation. These pathological conditions are believed to be caused by the exposure of blood elements to excessive hemodynamic stresses induced by the complex, turbulent flow field in the vicinity of the mechanical prosthesis. Therefore, a critical prerequisite for improving and further refining existing MPHV designs is the in-depth understanding of the flow fields they induce. A 5-year research plan is proposed herein aimed at developing and validating a state-of-the art numerical simulation tool for obtaining quantitatively accurate predictions of all flow phenomena occurring in prosthetic valves. The specific aims for the proposed research program are: 1) To develop a highly accurate and efficient numerical method for simulating unsteady, three-dimensional flows in realistic bileaflet MPHV geometries; 2) To develop and implement in MPHV flow simulations advanced turbulence closure models capable of accurate predictions of transition to turbulence and relaminarization in pulsatile flows at physiological Reynolds numbers; 3) To conduct detailed laboratory experiments to obtain comprehensive data sets and use these data sets to validate and fine-tune the CFD model; and 4) To apply the CFD method to study in detail the structure of turbulence in bi-leaflet MPHV designs and explore its implications to clinically observed complications. The proposed CFD method will revolutionize current valve design and testing practices. The method will be capable of yielding descriptions of the valve flow fields at a level of detail not currently accessible by experiments alone, leading to substantial time and cost savings during the research and development phase. This work will also lead to a computational framework for assessing the likelihood that implantation of a given MPHV design may lead to thromboembolic complications.

描述（由申请人提供）：目前机械人工心脏瓣膜（MPHV）的设计远非理想，并且在植入后经常出现严重的并发症，例如溶血、血小板破坏和血栓栓塞。这些病理状况被认为是由于血液成分暴露于机械假体附近复杂的湍流流场引起的过度血流动力学应力而引起的。因此，改进和进一步完善现有 MPHV 设计的关键先决条件是深入了解它们引起的流场。本文提出了一项为期 5 年的研究计划，旨在开发和验证最先进的数值模拟工具，以定量准确地预测人工瓣膜中发生的所有流动现象。拟议研究计划的具体目标是： 1) 开发一种高精度和高效的数值方法，用于模拟现实双叶 MPHV 几何形状中的不稳定三维流动； 2) 在 MPHV 流模拟中开发和实施先进的湍流闭合模型，能够准确预测生理雷诺数下脉动流的湍流转变和再层化； 3）进行详细的实验室实验，获得全面的数据集，并利用这些数据集来验证和微调CFD模型； 4) 应用CFD方法详细研究双叶MPHV设计中的湍流结构，并探讨其对临床观察到的并发症的影响。所提出的 CFD 方法将彻底改变当前的阀门设计和测试实践。该方法将能够以目前仅通过实验无法达到的详细程度产生阀门流场的描述，从而在研究和开发阶段节省大量时间和成本。这项工作还将形成一个计算框架，用于评估植入给定 MPHV 设计可能导致血栓栓塞并发症的可能性。