The Aortic Aneurysm is a pathological dilatation of the aorta. Approximately 80% of aortic aneurysms occur between the renal arteries and the aortic bifurcation in the abdominal tract. This disease is the 14th cause of death in United States. Each year in USA, abdominal aortic aneurysm rupture causes 4500 deaths with an additional 1400 deaths resulting from the 45000 prevent rupture procedures.
Rupture prevention consists in the implantation of a stent endograft to protect the vessel wall from the blood induced damage. There are many types of stents with different geometries. Indeed, geometry plays a crucial role in determining the fluid dynamics of the blood flow. Changes of the physiological geometry can generate complex flow patterns close to the aneurysm neck where the stent is fixed to the vessel. Under pulsatile flow conditions, the geometry induced vorticity can lead to an alteration of an important physio-pathologial parameter represented by the wall shear stress (WSS). The alteration of WWS causes an inflammatory response of the endothelial cells with subsequent thrombus formation (and embolization), aneurysm neck dilatation and stent migration.
The complexity of the problem requires strongly inter-disciplinary skills ranging from the clinical and surgical expertise to fluid dynamics understanding of unsteady flows in complex geometries. The aim of the present proposal is to analyse the hemodynamics modifications caused by different geometries, namely the Gore and Nellix prosthesis used in recent years.
The study will be carried out by a research team composed by vascular surgeons and engineers with specific skills in theirs fields. The clinical staff will provide actual geometries of treated abdominal aortic aneurysms, whilst the engineer team will carry out targeted experiments and numerical simulations to investigate the ensuing WSS. The clinical course will be monitored to correlate actual data on patients with their specific hemodynamical simulation.
