Simulation of the fluid dynamics in artificial aortic roots: comparison of two different types of prostheses.

As a consequence of the growing number of elderly people, the incidence of degenerative aortic diseases continues to increase. Often, artificial aortic roots are needed to replace the native tissue. Some physical characteristics of the artificial aortic root, however, are quite different from native aorta and need to be optimized. The supposed benefit of a prosthesis with artificial sinuses of Valsalva could first be checked by numerical calculations. Two simplified base geometries were used for simulating the flow and pressure distributions, especially in the coronary arteries. One model approximates the ascending aorta as a tube, and the other uses a design with toroidal dilation of the aortic root to approximate the native geometry of the sinuses of Valsalva. The flow and pressure distributions in both models were compared in the ascending aorta as well as in the right and the left coronary arteries. Both the pressure and the velocity distribution in the coronary artery region were not significantly higher in the model with the sinus design compared to the tube model. The sinus design only slightly increased the mean pressures and the velocities in both the ascending aorta and in the coronary arteries. Higher pressure in the coronary arteries should improve the blood circulation and decrease the risk of a surgery-related coronary incident. The sinus design did not show the hoped-for benefits, and therefore it is only a minor factor in optimizing future aortic root prostheses.