Computational haemodynamic analysis of patient-specific virtual operations for total cavopulmonary connection with dual superior venae cavae

Objectives: 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. Methods: 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. Results: 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. Conclusions: 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.