Study Of Hemodynamic Characteristics On Aortic Dissection Of A Patient-specific

Aortic dissection is a cardiovascular disease,which is a serious threat to human health.Although the emergence of endovascular graft exclusion of surgical treatment for aortic dissection has brought the revolutionary change,there are still many undecided factors.The occurrence and development of AD is intimately related to the high blood pressure.The research of hemodynamic changes after AD and blood dynamics in aorta after endovasculal graft exclusion has important meaning to clinical prevention of AD.To explore the influence of high blood pressure and endovascular graft exclusion to the development of AD,establish the individualized model of pre-and post-endovascular repair on Stanford B aortic dissection based on the CTA images.A series of hemodynamic parameters under normal blood pressure and hypertension were calculated by numerical simulation and compared.The research results provide useful reference for endovascular repair,which has important clinical significance.The main contents of each chapters as follows:In the first chapter,the definition,classification,examination and treatment of aortic dissection are introduced.The progress of hemodynamics research of aortic dissection at home and abroad is reviewed,and the main contents of this paper are introduced.In the second chapter,two methods of model construction in numerical simulation of aortic dissection are introduced,and the whole process of individualized aortic dissection is described in detail.Personalized model reconstruction mainly includes the following processes:1.Obtain the tomographic image;2.Split the tomographic image;3.Reconstruction and optimization of the three-dimensional model.Chapter 3 introduces the control equations and numerical methods of hemodynamics.The numerical calculation model of aortic dissection is described in detail,including grid partitioning,time step setting,selection of flow model,setting of physical parameters,setting of boundary condition,and sensitivity to grid and time step is tested.Chapter 4 analyzes the hemodynamic behavior.In the preoperative model,the blood flow velocity,wall pressure and wall shear stress of the heart systolic and short reflux were significantly changed.The diastolic blood flow velocity,wall pressure and wall shear stress did not significantly change The flow pattern within the false lumen begins to become disordered at the systolic end,and the streamline within the real lumen begins to become disordered during the brief reflow.In the postoperative model,the blood flow velocity,the wall pressure and the wall shear stress did not change drastically throughout the cardiac cycle,and the flow line began to become chaotic in the short reflow period.Chapter 5 analyzes the results of normal blood pressure and hypertension.Hypertension will have a greater impact on wall pressure,but does not have a significant effect on wall shear stress,blood flow velocity,blood flow rate ratio,TAWSS and OSI values.Chapter 6 analyzes the results of preoperative and postoperative.It was found that endovascular repair could effectively reduce the load on the wall of the aorta.The blood flow velocity,wall pressure and shear stress decreased after operation.At the same time surgery can change the main branches of the aorta blood flow distribution,and the left subclavian artery and descending aorta blood flow greater impact.The seventh chapter summarizes the work of the whole thesis,and prospects the future research.