Sun Qi, Liu Jinlong, Qian Yi, Zhang Haibo, Wang Qian, Sun Yanjun, Hong Haifa, Liu Jinfen
Department of Cardiothoracic Surgery, Shanghai Children's Medical Centre, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Eur J Cardiothorac Surg. 2014 Mar;45(3):564-9. doi: 10.1093/ejcts/ezt394. Epub 2013 Jul 31.
This study set out to design different types of total cavopulmonary connections (TCPC) with dual superior venae cavae (SVC), taking into account different sites for anastomosis from venae cavae to pulmonary arteries (PAs), and to compare haemodynamic features in these virtual operative designs.
The geometries of bilateral bidirectional Glenn (BBDG) connection and inferior vena cava (IVC) connected extracardiac conduit were reconstructed to three-dimensional configurations according to the magnetic resonance images (MRIs) of two patients at the same age, and virtual operations were designed to create four possible TCPC models under the guidance of paediatric cardiac surgeons. Computational fluid dynamic (CFD) simulations were performed in each model at five predetermined pulmonary flow splits, to predict postoperative blood flows. The same boundary conditions were applied on each model, in order to simplify the analysis of the influence of configurations on the flow characteristics. Control volume power losses and energy efficiency in different models were calculated and compared. Flow patterns in the models were demonstrated by streamlines corresponding to the venae cavae.
When the flow rate of the right pulmonary artery (RPA) was 40-60% of the total pulmonary flow, control volume power loss was lower than the other three models in the model of TCPC 2 and was higher than the other three models in the model of TCPC 4.
For this patient, anastomosing the left superior vena cava (LSVC) and right superior vena cava (RSVC) on the PAs close together will cause higher power loss and lower energy efficiency in the TCPC connection. If the LSVC and RSVC had been connected to the PAs as near as possible to stimulate growth of the central PAs when performing I-stage BBDG procedure, the extracardiac conduit from IVC would be better connected just under the anastomotic site in the following TCPC procedure to avoid high power loss.
本研究旨在设计不同类型的双上腔静脉全腔肺连接（TCPC），考虑从腔静脉到肺动脉（PA）的不同吻合部位，并比较这些虚拟手术设计中的血流动力学特征。
根据两名同龄患者的磁共振成像（MRI），将双侧双向格林（BBDG）连接和下腔静脉（IVC）连接的心外管道的几何形状重建为三维构型，并在小儿心脏外科医生的指导下设计虚拟手术，以创建四种可能的TCPC模型。在每个模型中，针对五个预定的肺血流分流进行计算流体动力学（CFD）模拟，以预测术后血流。对每个模型应用相同的边界条件，以简化对构型对流动特性影响的分析。计算并比较不同模型中的控制体积功率损失和能量效率。通过与腔静脉相对应的流线展示模型中的流动模式。
当右肺动脉（RPA）的流速为总肺血流的40% - 60%时，在TCPC 2模型中控制体积功率损失低于其他三个模型，而在TCPC 4模型中高于其他三个模型。
对于该患者，在肺动脉上靠近吻合左、右上腔静脉会导致TCPC连接中功率损失更高且能量效率更低。如果在进行I期BBDG手术时将左、右上腔静脉尽可能靠近地连接到肺动脉以刺激中央肺动脉生长，那么在接下来的TCPC手术中，来自下腔静脉的心外管道应更好地连接在吻合部位下方，以避免高功率损失。
