Numerical Simulation And Case Analysis Of Hemodynamics Of Infantile Aortic Coarctation

Computational Fluid Dynamics(CFD)can be used to simulate cardiovascular hemodynamic information,which is expected to achieve non-invasive intelligent diagnosis and surgical treatment plan design for coarctation of aorta(COA)cases.In this study,the threedimensional models of the aorta of different patients were established based on the computed tomography images of COA patients,and the geometric multi-scale coupling boundary conditions of the computational domain were constructed based on the three-element Windkessel model to completed the hemodynamic numerical simulation of COA cases.The application of CFD simulation technology in the diagnosis and treatment of COA cases was thoroughly explored from different perspectives to provide more comprehensive hemodynamic reference information for clinicians.The results of measuring the aortic pressure drop and the flow velocity at the constriction of COA cases through CFD simulation and Doppler ultrasound respectively have a strong correlation.The average difference value between CFD simulation and ultrasound measurement was 10.43% and 5.88%,respectively,indicating that it is feasible to use this simulation method to assist in the diagnosis of COA cases.The hemodynamic parameters obtained by CFD simulation can further evaluate the severity of COA cases.The lower energy conversion efficiency may represent the more severe COA symptoms.The larger the area of the high wall shear stress area can also reflect the increased risk of thrombosis caused by COA.For COA cases accompanied by patent ductus arteriosus(PDA),the conduction of PDA will reduce the pressure drop of the aorta and the blood flow rate at the constriction,which leads to the early reduction of COA-related symptoms in COA-PDA patients.The hemodynamic environment of certain COA-PDA study cases will deteriorate as the PDA gradually closes.Comparing the PDA from the fully conductive state to the complete closed state,the aortic pressure drop increased by 43.2%,the energy conversion efficiency decreased from 94.29% to 88.61%,and the average energy loss increased from 11.48 m W to 21.91 m W.Therefore,the clinic can consider delaying the closure of the PDA and try to perform surgical treatment on the COA before the PDA completely closed.Expanded end-to-end or end-to-side anastomosis and expanded patch anastomosis models have very significant effects on improving the hemodynamic environment of COA cases.The aortic pressure drop values after the virtual operation were all less than 15 mm Hg,the blood flow velocity at the constriction decreased from 2.50m/s～3.57m/s to the normal range of1.43m/s～1.83m/s,the lowest increase of blood flow in the descending aorta was 5.7%,and the energy conversion efficiency increased from 88.26%-93.37% to more than 94.5%.The three different surgical plans have different hemodynamic in specific COA cases.Therefore,when clinically using CFD to assist in the design of surgical plans,personalized virtual surgical design and simulation analysis for different patients should be established.