Image-based immersed boundary model of the aortic root.
Image-based immersed boundary model of the aortic root.
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DOI：
10.1016/j.medengphy.2017.05.007
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发表时间：
2017-09
影响因子：
2.2
通讯作者：
Griffith BE
中科院分区：
文献类型：
--
作者：
Hasan A;Kolahdouz EM;Enquobahrie A;Caranasos TG;Vavalle JP;Griffith BE
每年，全世界大约进行 300,000 例心脏瓣膜修复或置换手术，其中仅在美国就进行了大约 70,000 例主动脉瓣置换手术。用于模拟人工心脏瓣膜等心血管设备的计算平台有望改进设备设计并协助治疗计划，包括针对患者的特定设备选择。本文描述了构建主动脉根部和升主动脉动力学的解剖学和生理学真实浸没边界（IB）模型的进展。这项工作建立在主动脉根部流体-结构相互作用 (FSI) 的早期 IB 模型的基础上，该模型之前在多个心动周期内实现了真实的血流动力学，但也仅限于简化的主动脉几何形状和主动脉瓣尖部生物力学的理想化描述。相比之下，本文描述的模型使用根据患者特异性计算机断层扫描血管造影（CTA）数据重建的解剖几何形状，并采用基于与实验拉伸测试数据拟合的纤维增强本构模型的主动脉瓣叶弹性描述。由此产生的模型会产生收缩期和舒张期的生理压力，并以生理雷诺数产生真实的心输出量和每搏输出量。舒张期间瓣膜小叶之间的接触由 IB 方法自动处理，产生完全合格的瓣膜模型，支持生理舒张压力负荷而无需反流。数值测试表明，该模型能够在实际网格间距下解析舒张期和收缩早期的小叶生物力学。该模型还用于检查新鲜瓣膜小叶和戊二醛固定小叶产生的力学和流体动力学差异，类似于生物假体心脏瓣膜中使用的小叶。尽管舒张期间的小叶变形存在很大差异，但瓣膜模型的开放配置的差异相对较小，并且在所有考虑的情况下都获得了几乎相同的血流动力学。
Each year, approximately 300,000 heart valve repair or replacement procedures are performed worldwide, including approximately 70,000 aortic valve replacement surgeries in the United States alone. Computational platforms for simulating cardiovascular devices such as prosthetic heart valves promise to improve device design and assist in treatment planning, including patient-specific device selection. This paper describes progress in constructing anatomically and physiologically realistic immersed boundary (IB) models of the dynamics of the aortic root and ascending aorta. This work builds on earlier IB models of fluid-structure interaction (FSI) in the aortic root, which previously achieved realistic hemodynamics over multiple cardiac cycles, but which also were limited to simplified aortic geometries and idealized descriptions of the biomechanics of the aortic valve cusps. By contrast, the model described herein uses an anatomical geometry reconstructed from patient-specific computed tomography angiography (CTA) data, and employs a description of the elasticity of the aortic valve leaflets based on a fiber-reinforced constitutive model fit to experimental tensile test data. The resulting model generates physiological pressures in both systole and diastole, and yields realistic cardiac output and stroke volume at physiological Reynolds numbers. Contact between the valve leaflets during diastole is handled automatically by the IB method, yielding a fully competent valve model that supports a physiological diastolic pressure load without regurgitation. Numerical tests show that the model is able to resolve the leaflet biomechanics in diastole and early systole at practical grid spacings. The model is also used to examine differences in the mechanics and fluid dynamics yielded by fresh valve leaflets and glutaraldehyde-fixed leaflets similar to those used in bioprosthetic heart valves. Although there are large differences in the leaflet deformations during diastole, the differences in the open configurations of the valve models are relatively small, and nearly identical hemodynamics are obtained in all cases considered.
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影响因子：
3.8
作者：
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通讯作者：
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DOI：
10.1002/cnm.2652
发表时间：
2014-11
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