Predicting the formation of aortic dissection using a non-Newtonian model / 中国医学物理学杂志

The blood flow in the aortic arch and branch vessels in vitro is simulated,and the blood model is optimized with a non-Newtonian model.A numerical simulation analysis is conducted based on bidirectional fluid-solid coupling to analyze the hemodynamic characteristics(blood flow velocity,vascular wall pressure and vascular wall stress)in a cardiac cycle,and discuss their relationships with the formation of aortic dissection.It is concluded that the long-term existence of"chaotic"blood flow distribution in the blood vessel and the sudden changes of wall pressure and wall stress are liable to cause changes in the structure and function of the cells of the arterial wall,and ultimately induce the formation of aortic dissection.The study provides a more reliable basis for medical diagnosis,and further protects the life,health and safety of patients.

The effects of sand treatment in Uyghur medicine on the pulsatile hemodynamics of femoral artery bidirectional fluid-solid coupling / 介入放射学杂志

Objective To investigate the effects of Uyghur indoor sand therapy on the hemodynamics of femoral artery bidirectional fluid-solid coupling,and to discuss the influence of Uyghur indoor sand therapy on the formation of atherosclerosis as well as on the rupture of blood vessels.Methods This study of indoor Uyghur sand therapy was conducted in young healthy volunteers.The heart rate,peak value of femoral artery blood flow velocity and inner diameter were determined,and the results were statistically analyzed.Three dimensional fluid-solid coupling model of human femoral artery was reconstructed.Taking the sine function as the initial condition,the non-steady field bidirectional fluid-solid coupling simulation was conducted by using Fluent software,and the effect of indoor Uyghur sand therapy on femoral artery wall shear stress as well as on yon Mises equivalent stress was evaluated.Results The average heart rates before and after indoor Uyghur sand therapy were (76.32±11.40) beats per minute and (92.69±16.09) beats per minute respectively,the difference was statistically significant (P＜0.05).The Renolds number of femoral artery before and after indoor Uyghur sand therapy was 1855.35 and 2518.4 respectively.The Uyghur sand therapy had more obvious influence on the increase of femoral artery wall shear stress and von Mises equivalent stress.Conclusion Uyghur sand therapy can increase Renolds number of femoral artery and improve the blood flow state of human femoral artery,but after the treatment the femoral artery blood flow pattern changed from laminar flow to turbulence flow,which may lead to the formation of hemangioma,therefore,for patients whose inner wall of blood vessel are thinner the sand-buried time,burying-sand thickness and temperature should be strictly controlled.Uyghur sand therapy can also increase wall shear stress,which plays a certain positive role in preventing atherosclerosis and thrombosis caused by thickening of the arterial wall.After Uyghur sand therapy,the von Mises equivalent stress is remarkably increased,which can increase the possibility of angiorrhexis at femoral artery bifurcation,thus,full attention should be paid to patients during the performance of Uyghur sand therapy.