COMPUTATIONAL FLUID DYNAMICS OF TYPE B AORTIC DISSECTION

Type B aortic dissection (AoD) is a disease connected to high blood load on the aortic wall and to a reduced aortic wall resistance. Nowadays, prognosis on type B AoD results to be particularly difficult with an high incidence of patients treated with medical therapy which manifest complication connected with dissection and which should have been treated with surgical repair immediately. This work aims to study those haemodynamical and morphological proprieties of dissected aorta, which can influence the progression or stability of type B AoD. Computational fluid-dynamic analyses were performed on twenty-five patients with type B AoD, whose nine presented an aneurysm evolution and sixteen presented no further complication connected with dissection. Blood flow features showed that the true lumen flow was laminar and uniform while false lumen flow was less homogeneous with a consequent recirculating path. We found that entry point zone proximal to the aortic arch showed both high blood velocity and pressure connected with peaks of maximum WSS value. Moreover, a negative pressure gradient between the false lumen entry and re-entry points was observed. This promotes the blood to flow towards the abdominal aorta reducing the risk of retrograde flow during systole. We concluded that fluid dynamics study of patients with type B AoD is a valid tool to identify the risk of aortic dissection progression as well as the formation of pathology connected with aortic dissection.