3D Hemodynamic Simulation And Case Analysis Of Systemic-to-pulmonary Shunt

For patient with cyanotic congenital heart disease who do not meet the requirements for radical surgery,systemic to pulmonary shunt is usually used to increase blood oxygen saturation,relieve cyanosis and promote pulmonary artery development.In this paper,three kind of main and pulmonary artery model with both left and right pulmonary artery stenosis,unilateral left pulmonary artery(LPA)stenosis,and unilateral right pulmonary artery(RPA)stenosis were constructed based on the CT images and clinical data of the research case.3WK multi-scale coupling model of systemic to pulmonary shunt was used for numerical simulation.The hemodynamic characteristics of CS,MBTS,and shunt configurations under six PDA diameter were evaluated by flow field visualization and hemodynamic parameters to provide theoretical support for choosing the optimal surgical schemes.For models with both right and left pulmonary artery stenosis and unilateral right pulmonary artery stenosis,the LPA and RPA flow split ratio were 0.87 and 1.14 for MBTS,and 2.17 and 5.22 for CS.The results show that for models with both left and right pulmonary artery stenosis and unilateral right pulmonary artery stenosis,MBTS can promote uniform distribution of left and right pulmonary blood flow.For patients with unilateral left pulmonary artery stenosis,the LPA and RPA flow split ratio were 1.34 for CS and 0.54 for MBTS,which means that CS can provide a more uniform left and right pulmonary blood flow distribution.In addition,CS can provide a higher shunt ratio and and lower energy loss compared with MBTS,which indicatied that CS can reduces the chance of postoperative cardiac overload.Under the three kind of main and pulmonary artery model,the LPA and RPA flow split ratio of CS were 1.07,0.97,and 2.06 when the PDA was opening;the LPA and RPA flow split ratio of CS were 2.17,1.34,and 5.22 when the PDA was closed.The simulation results show that the flow distribution of LPA and RPA was more uniform for CS when the PDA was opening.Moreover,the energy loss of the CS was lower,and the shear stress distribution was more uniform when the PDA was opening.For three kind of main and pulmonary artery model,the ratio of shear stress area that can cause thrombus formation to total surface area were 1.1%,1.2%,and 1.4% when the PDA was opening and 3.6%,3.5% and 3.3% when the PDA was closed.Simulation results show that the probability of shunt failure in the MBTS operation is smaller.Therefore,in order to avoid the phenomenon of shunt failure after MBTS,it should be considered to retain the PDA during the operation.