Galway Medical Technology Centre, Department of Mechanical and Industrial Engineering (GMIT), Galway, Ireland.
Department of Cardiothoracic Surgery, Children's Health Ireland, Crumlin, Dublin 12, Ireland.
J Cardiothorac Surg. 2020 Sep 2;15(1):235. doi: 10.1186/s13019-020-01269-x.
OBJECTIVE(S): The Fontan procedure is a common palliative intervention for sufferers of single ventricle congenital heart defects that results in an anastomosis of the venous return to the pulmonary arteries called the total cavopulmonary connection (TCPC). In patients with palliated single ventricular heart defects, the Fontan circulation passively directs systemic venous return to the pulmonary circulation in the absence of a functional sub-pulmonary ventricle. Therefore, the Fontan circulation is highly dependent on favourable flow and energetics, and minimal energy loss is of great importance. The majority of in vitro studies, to date, employ a rigid TCPC model. Recently, few studies have incorporated flexible TCPC models, without the inclusion of commercially available conduits used in these surgical scenarios.
The methodology set out in this study successfully utilizes patient-specific phantoms along with the corresponding flowrate waveforms to characterise the flow haemodynamic performance of extracardiac Gore-Tex conduits. This was achieved by comparing a rigid and flexible TCPC models against a flexible model with an integrated Gore-Tex conduit.
The flexible model with the integrated Gore-Tex graft exhibited greater levels of energy losses when compared to the rigid walled model. With this, the flow fields showed greater levels of turbulence in the complaint and Gore-Tex models compared to the rigid model under ultrasound analysis.
This study shows that vessel compliance along with the incorporation of Gore-Tex extracardiac conduits have significant impact on the flow haemodynamics in a patient-specific surgical scenario.
Fontan 手术是治疗单心室先天性心脏缺陷患者的常见姑息性干预措施，导致静脉回流到肺动脉的吻合术称为全腔静脉肺动脉连接（TCPC）。在姑息性单心室心脏缺陷患者中，Fontan 循环在没有功能性亚肺心室的情况下被动地将体循环静脉回流引导至肺循环。因此，Fontan 循环高度依赖于有利的流动和能量，最小的能量损失非常重要。迄今为止，大多数体外研究都采用刚性 TCPC 模型。最近，一些研究已经纳入了柔性 TCPC 模型，但没有纳入这些手术场景中使用的商业上可用的导管。
本研究中提出的方法成功地利用了患者特定的体模以及相应的流量波形来描述体外戈尔-泰克斯导管的血流动力学性能。这是通过将刚性和柔性 TCPC 模型与带有集成戈尔-泰克斯导管的柔性模型进行比较来实现的。
与刚性壁模型相比，带有集成戈尔-泰克斯移植物的柔性模型表现出更高的能量损失水平。在超声分析中，与刚性模型相比，抱怨和戈尔-泰克斯模型中的流场显示出更大程度的湍流。
本研究表明，血管顺应性以及戈尔-泰克斯体外导管的纳入对特定于患者的手术情况下的血流动力学有重大影响。
