Impact of blood viscosity on wall shear stress of large intracranial aneurysms

Abstract

Objective To simulate the computational hemodynamics of large intracranial aneurysms and analyze the impact of blood viscosity on wall shear stress. Methods Eight large intracranial aneurysms at internal carotid artery between June 2013 and July 2013 were studied retrospectively. Among them,3 aneurysms were ruptured and 5 were unruptured.Pulsatile CFD simulations were carried out using three levels of blood viscosity(0.002,0.004,0.012 Pa·s).For each aneurysm model, the average wall shear stress(WSS) predicted by the three blood viscosity levels were compared. Results Blood viscosity has significant impaction on average wall shear stress of intracranial aneurysms and parent artery.Average wall shear stress increased significantly with the increase of blood viscosity.When blood viscosity was 0. 002,0. 004,0. 012 Pa·s,the average wall shear stress of aneurysms was(2. 79±2. 23),(5. 27±3. 72)and(11. 05±7. 56)Pa,respectively.The average wall shear stress of parent artery was(5. 61±2. 59),(9. 56±3. 74)and(22. 56±12. 41) Pa respectively.A reduction in wall shear stress between the parent artery and the aneurysm sac was found in all the cases. Conclusion Abnormal increase or decrease in blood viscosity may aggravate vascular wall damage and increase the risk of aneurysmal rupture.It is necessary to adopt patient-specific value of blood viscosity in future hemodynamic studies of intracranial aneurysms. Key words: Blood viscosity; Large intracranial aneurysm; Wall shear stress; Hemodynamics