Computational Fluid Dynamics Method Analyses Malperfusion Of Organs In Aortic Dissections

Objectives:Aortic dissection is a common cardiovascular disease,and it is an acute disease with high mortality.It refers to the aortic endovascular blood entering the aortic membrane from the tear of the aortic intima,which separations the middle membrane and expands along the aorta long axis to form the true and false two chamber separation state of the aortic wall.Research shows that the hemodynamic parameters such as wall shear stress,pressure and velocity of blood flow,have connections with the occurrence and development of interlayer.Hemodynamic characteristics are closely related to vascular geometry,and hemodynamic changes were closely related to postoperative complications.Therefore,we can get the individual morphological data of the dissection patients,carrying out hemodynamic analysis based on individual models,and assess the risk of organ perfusion defects based on this model,and formulate preventive measures and treatment programs.The risk of postoperative complications such as organ perfusion and other complications should be evaluated,so as to provide new methods for making corresponding clinical treatment plans for patients with such diseases.Methods: We collected the CT image data of 20 patients with aortic dissection in the First Affiliated Hospital of China Medical University from 2015 to 2017.The patients were divided into two groups according to the postoperative liver and kidney function: The hepatorenal insufficiency group,and No hepatorenal dysfunction group.A medical image processing code is used to simulate the reconstruction of thoracic aorta model from CT angiography images of DICOM format.The unsteady blood flow simulates the real geometry of the thoracic aorta by using the FVM software ANSYS fluent15.0.We analysis the connections between the hemodynamic parameters of the formation of thoracic and abdominal aortic dissection and postoperative organ dysfunctionResults: The anatomy of the ascending aorta,the abdominal trunk of the aortic arch,the superior mesenteric artery,the double renal artery and the bilateral iliac arteries were reconstructed by the medical simulation software MIMICS17.0.The blood flow field was simulated on the reconstructed aortic anatomy model.The numerical results obtained the hemodynamic parameters of the intra-aortic blood in patients with aortic dissection,such as the pressure of the blood vessel wall and the velocity of blood flow at a certain time of blood flow in the blood vessel.By comparing the hemodynamic parameters of the aorta and its branches between the liver and kidney function damage groups,the following results were deduced: Comparative analysis of aorta and branch in hemodynamic parameters between the normal group and the complications,the blood flow velocity and aortic branch vessels faster,the rate of organ mal-perfusion is lower.The aorta and branch vascular wall shear stress increases,the rate of adverse postoperative organ perfusion is lower.Conclusion: The research of hemodynamics is a hot research topic in cardiovascular system.Computational fluid dynamics analysis is a reliable method for its research.A three-dimensional model of individual thoracic and abdominal aorta and its branch vessels in patients with aortic dissection was obtained by using the method of 3D reconstruction of medical human simulation and dissection software,which lay the foundation for further research and analysis of liver and kidney function damage and hemodynamic system after aortic dissection.By analyzing the hemodynamic simulation results of aortic dissection patients before operation,we can predict the prognosis after operation.The risk of liver and kidney dysfunction,such as poor organ perfusion after operation,is evaluated to provide a new method for the formulation of the corresponding clinical treatment scheme for the patients with such aortic disease.