Hemodynamic comparison between elastic and rigid vessels for the central shunt / 医用生物力学

Objective To study the hemodynamics of central shunt (CS) by numerical simulation and investigate the effects of the elastic and rigid vessel wall on distributions of hemodynamic parameters in the vessel. Methods Two idealized CS models were constructed, one with a rigid wall (the rigid model) and the other with an elastic wall (the elastic model). Numerical calculation was conducted by the finite element method, and the elastic model adopted the fluid structure interaction. Results The distribution of flow velocity and pressure in both models were generally the same. About 68.9% of the aortic blood was directed into the pulmonary artery for the rigid model, as compared to 70% for the elastic model. The pressure drops within the shunt for the elastic model and rigid model were about 7.668 8 kPa and 7.222 3 kPa, respectively. The maximum variation in the average cross sections along the shunt was about 2.2% for the elastic model, appearing at the proximal end to side (ETS) anastomosis. The maximum difference of wall shear stress (WSS) between the two models at five key regions of each was about 16.1%. Conclusions Generally, the global flow structure in both the CS models remains unchanged; the elasticity of the vessel wall slightly influenced the flow distributions and pressure drop of the shunt; the effect from elasticity of the vessel wall on average cross sections along the shunt was higher at the proximal ETS anastomosis than that at the distal ETS anastomosis; the hypothesis that the vessel wall is rigid is acceptable in CS numerical simulations for the treatment of tetralogy of Fallot (TOF). However, the coupling of flow dynamics and wall mechanics may lead to a more reliable simulation result in the CS.

Midterm Results of Modified Central Shunt in Patients of Pulmonary Atresia with Ventricular Septal Defect: Two cases report / 대한흉부외과학회지

We operated on two neonates with a technical modification of the standard central shunt. The anatomic diagnosis was pulmonary atresia with ventricular septal defect and patent ductus arteriosus. In operation, the aorto - shunt graft anastomosis was created in a side-to-side ashion. During follow-up both pulmonary arteries and main pulmonary artery were well grown. And when the patients were 10 and 18 months of age, Lecompte procedures were Performed. This technique has the advantage of creating a short, straight-lying shunt that is less like to kink.