Division of Transplant Surgery, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya City, Aichi, 466-8550, Japan.
Department of Mechanical Engineering, Nagoya Institute of Technology, Nagoya, Aichi, 466-8555, Japan.
J Gastrointest Surg. 2020 Feb;24(2):460-461. doi: 10.1007/s11605-019-04279-w. Epub 2019 Sep 4.
Portal vein stenosis develops in 3.4-14% of split liver transplantation- and its early detection and treatment are essential to achieve long-term graft survival,- although the diagnostic capability of conventional modalities such as Doppler ultrasound and computed tomography is limited.,, METHODS: This study used computational fluid dynamics to analyze portal vein hemodynamics in the management of post-transplant portal vein stenosis. To perform computational fluid dynamics analyses, three-dimensional portal vein model was created using computed tomographic DICOM data. The inlet flow condition was set according the flow velocity measured on Doppler ultrasonography. Finally, portal vein flow was simulated on a fluid analysis software (Software Cradle, Japan).
An 18-month-old girl underwent liver transplantation using a left lateral graft for biliary atresia. At the post-transplant 1-week evaluation, the computational fluid dynamics streamline analysis visualized vortices and an accelerated flow with a velocity ratio < 2 around the anastomotic site. The wall shear stress analysis revealed a high wall shear stress area within the post-anastomotic portal vein. At the post-transplant 6-month evaluation, the streamline analysis illustrated the increased vortices and worsening flow acceleration to reach the proposed diagnostic criteria (velocity ratio > 3:1)., The pressure analysis revealed a positive pressure gradient of 3.8 mmHg across the stenotic site. Based on the findings, the patient underwent percutaneous transhepatic portal venoplasty with balloon dilation. The post-treatment analyses confirmed the improvement of a jet flow, vortices, a high wall shear stress, and a pressure gradient.
The computational fluid dynamics analyses are useful for prediction, early detection, and follow-up of post-transplant portal vein stenosis and would be a promising technology in post-transplant management.
在劈离式肝移植中，门静脉狭窄的发生率为 3.4%-14%，早期发现和治疗对于实现长期移植物存活至关重要，尽管多普勒超声和计算机断层扫描等常规影像学方法的诊断能力有限。
本研究使用计算流体动力学分析在移植后门静脉狭窄的管理中的门静脉血流动力学。为了进行计算流体动力学分析，使用计算机断层扫描 DICOM 数据创建了门静脉的三维模型。根据多普勒超声测量的流速设定入口流量条件。最后，在流体分析软件（日本 Software Cradle）上模拟门静脉血流。
一名 18 个月大的女孩因胆道闭锁接受了左外侧叶供肝的肝移植。在移植后 1 周的评估中，计算流体动力学流线分析可视化了吻合口周围的涡流和速度比<2 的加速血流。壁面切应力分析显示吻合口后门静脉内存在高壁面切应力区域。在移植后 6 个月的评估中，流线分析显示涡流增加，血流加速恶化，达到了拟议的诊断标准（速度比>3:1）。压力分析显示狭窄部位的正压力梯度为 3.8mmHg。根据这些发现，患者接受了经皮经肝门静脉成形术球囊扩张。治疗后的分析证实了射流、涡流、高壁面切应力和压力梯度的改善。
计算流体动力学分析有助于预测、早期发现和随访移植后门静脉狭窄，并且是移植后管理中有前途的技术。
