Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0411, USA.
J Thorac Cardiovasc Surg. 2012 May;143(5):1086-97. doi: 10.1016/j.jtcvs.2011.06.042. Epub 2011 Sep 29.
A novel Y-shaped baffle has been proposed for the Fontan operation with promising initial results. However, previous studies have relied either on idealized models or a single patient-specific model. The objective of this study is to comprehensively compare the hemodynamic performance and hepatic blood flow distribution of the Y-graft Fontan baffle with 2 current designs using multiple patient-specific models.
Y-shaped and tube-shaped grafts were virtually implanted into 5 patient-specific Glenn models forming 3 types of Fontan geometries: Y-graft, T-junction, and offset. Unsteady flow simulations were performed at rest and at varying exercise conditions. The hepatic flow distribution between the right and left lungs was carefully quantified using a particle tracking method. Other physiologically relevant parameters such as energy dissipation, superior vena cava pressure, and wall shear stress were evaluated.
The Fontan geometry significantly influences the hepatic flow distribution. The Y-graft design improves the hepatic flow distribution effectively in 4 of 5 patients, whereas the T-junction and offset designs may skew as much as 97% of hepatic flow to 1 lung in 2 cases. Sensitivity studies show that changes in pulmonary flow split can affect the hepatic flow distribution dramatically but that some Y-graft and T-junction designs are relatively less sensitive than offset designs. The Y-graft design offers moderate improvements over the traditional designs in power loss and superior vena cava pressure in all patients.
The Y-graft Fontan design achieves overall superior hemodynamic performance compared with traditional designs. However, the results emphasize that no one-size-fits-all solution is available that will universally benefit all patients and that designs should be customized for individual patients before clinical application.
一种新型的 Y 型挡板已被提出用于 Fontan 手术，其初始结果令人鼓舞。然而，之前的研究要么依赖于理想化的模型，要么依赖于单个患者特定的模型。本研究的目的是使用多个患者特定的模型全面比较 Y 型移植物 Fontan 挡板与 2 种现有设计的血流动力学性能和肝血流分布。
将 Y 型和管型移植物虚拟植入 5 个患者特定的 Glenn 模型中，形成 3 种 Fontan 几何形状：Y 型移植物、T 型连接和偏移。在休息和不同运动条件下进行非定常流模拟。使用粒子跟踪法仔细量化右肺和左肺之间的肝血流分布。评估了其他与生理相关的参数，如能量耗散、上腔静脉压力和壁面切应力。
Fontan 几何形状显著影响肝血流分布。在 5 名患者中的 4 名中，Y 型设计有效地改善了肝血流分布，而在 2 名患者中，T 型连接和偏移设计可能会将多达 97%的肝血流偏向 1 个肺。敏感性研究表明，肺血流分流的变化会显著影响肝血流分布，但某些 Y 型移植物和 T 型连接设计比偏移设计的敏感性相对较低。在所有患者中，Y 型设计在功率损失和上腔静脉压力方面比传统设计具有适度的优势。
与传统设计相比，Y 型移植物 Fontan 设计总体上实现了更好的血流动力学性能。然而，结果强调，没有一种通用的解决方案可以普遍使所有患者受益，并且在临床应用之前，应根据个体患者定制设计。
