Blood flow computational characterization inside an idealized saccular aneurysm in presence of magnetic field

The blood flow of a wide neck saccular cerebral aneurysm is modeled using numerical methods, before and after positioning a diverter flow or stent as endovascular treatment. Blood, as a magnetic fluid, is modeled computationally under the influence of different external magnetic fields. For this, a list of factors that can be varied in the external magnetic field configuration and, in turn, can affect the velocity field of the blood flow of the stented aneurysm is selected. By varying the amplitude, direction and frequency of the magnetic field, it is concluded that the amplitude has an incidence on blood velocity and shear stress in the regions where the aneurysm starts and in the stent spires. After studying the changes in blood flow, a suspension of idealized endothelial cells is computationally injected, the trajectory is modeled and the cells that are trapped on the stent spires are quantified. With this, it is possible to understand the changes in the flow conditions of the cells and to examine whether, when the blood flow is subjected to an external magnetic field, it is possible to trap endothelial cells in the region of the stent. Trapped cells finally would promote complete occlusion of the neck of the aneurysm through the stimulation of tissue growth called endothelialization.Resumen: El flujo de sangre de un aneurisma cerebral, sacular de cuello amplio, es modelado usando métodos numéricos, antes y después de posicionar un diversor de flujo o stent como tratamiento endovascular. La sangre, como fluido magnético, es modelada computacionalmente bajo la influencia de diferentes campos magnéticos externos. Para esto, se selecciona una lista de factores que pueden ser variados en la configuración del campo magnético externo y a su vez pueden afectar el campo de velocidades del flujo de sangre del aneurisma con stent. Al variar la magnitud, dirección y frecuencia del campo magnético, se concluye que la magnitud tiene incidencia en la velocidad de la sangre y en el esfuerzo cortante en las regiones donde se inicia el aneurisma y en las espiras del stent. Después de estudiar los cambios en el flujo de sangre, se inyectan computacionalmente una suspensión de células endoteliales idealizadas, se modela su trayectoria y se cuantifican las células que son atrapadas por las espiras del stent en la región del cuello del aneurisma. Con esto, es posible comprender los cambios en las condiciones de flujo de las células y examinar si cuando el flujo de sangre es sometido a un campo magnético externo, es posible atrapar células endoteliales en la región del stent para finalmente promover la oclusión completa del cuello del aneurisma a través del estímulo del crecimiento de tejido llamado endotelizaciónMaestrí

Simulations of Magnetohemodynamics in Stenosed Arteries in Diabetic or Anemic Models

Pulsatile flow simulations of non-Newtonian blood flow in an axisymmetric multistenosed artery, subjected to a static magnetic field, are performed using FLUENT. The influence of artery size and magnetic field intensity on transient wall shear stress, mean shear stress, and pressure drop is investigated. Three different types of blood, namely, healthy, diabetic, and anemic are considered. It is found that using Newtonian viscosity model of blood in contrast to Carreau model underestimates the pressure drop and wall shear stress by nearly 34% and 40%, respectively. In addition, it is found that using a magnetic field increases the pressure drop by 15%. Generally, doubling the artery diameter reduces the wall shear stress approximately by 1.6 times. Also increasing the stenosis level from moderate to severe results in reduction of the shear stress by 1.6 times. Furthermore, doubling the diameter of moderately stenosed artery results in nearly 3-fold decrease in pressure drop. It is also found that diabetic blood results in higher shear stress and greater pressure drop in comparison to healthy blood, whereas anemic blood has a decreasing effect on both wall shear stress and pressure drop in comparison to healthy blood