Effect Of Stent On Cerebral Intra-aneurysmal Hemodynamics And The Study On Restenosis

More and more researchers pay attention to the method of using stents treats the intracranial aneurysms through the way of minimally invasive surgery,But the technology will bring about the problem of intravascular restenosis after acertain period of time after surgery, and by means of simulation to explore this problem is a simple and effective way.Study the effects of stents on cerebral intra-aneurysmal hemodynamics and the distribution of wall shear stress on the surface of stents which caused by different variables,so as to explore the relationship between these variables and the restenosis after stenting.Based on an example of the image data of individualized intracranial aneurysms established a model of individualized intracranial aneurysms by the method of image extract,and on the basis of this model established three kinds of different structure stents through the three-dimensional modeling software.Thus exploring the effects three kinds stents model on the blood flow field and wall shear stess by the way of numerical simulation.Selecting a kind of stent model which has a good treatment to the individualized aneurysm.,and two wall shear strss which is less than 0.5Pa and more than 40 Pa danger zones that restenosis often occurred is selected as a standard,and distribution of shear stress that on the surface of stent and the surrounding parent artery is explored from three aspects of different blood flow velocity,different blood concentration and different thickness of stents.In this way this article reveal the relationship between different variables and restenosis.At the same time,the article analyzed the different structure of compliance and blood vessels in the radial supporting through the way of statics analysis.Through the way of simulation the blood streamline after a stent was inplanted into the aneurysm,the chart of wall shear stress and the chart of wall deformation was got,and the article found that the structure of spiral stent has a good improvement tothe vortex intensity in the aneurysm cavity,and the structure of cycle stent minimized the blood flow velocity range.At the same time,by changing the size of the above three variables at the same time,three different size variable conditions have been obtained respectively corresponding to the two prone zones to the distribution of restenosis.Through the observation,in a cardiac cycle,two kinds of dangerous area changes with the change of blood flow velocity.At the moment of 0.1s,the shear stress area which is greater than 40 Pa is the largest,from the 0.34 s to the before of next cardiac cycle,the area that wall shear stress is less than 0.5Pa remains the same and its distribution is the maximum.When blood viscosity increasing,the distribution of two risk area also increased.In the last exploring of the thickness of the stents,with the decrease of the thickness of stents the value of the wall shear stress on the surface the model decreased greatly,at the same time the floating of the shear stress value on the surface of the model decrease obviously.