The incidence of Abdominal Aortic Aneurysms (AAA) varies between 3% and 6% of the elder population, especially men over sixty years of age. Moreover, familiarity, smoking and peripherical atherosclerosis are known to be important risk factors. In the United States AAA ruptures cause about 9000 deaths every year. About 33000 elective surgical treatments per year are performer with a mortality of 1400–2800 patients. The percentage of success of surgical treatment remains strictly related to the diagnosis of the stage of the AAA. Mortality rate for elective surgical intervention (asymptomatic aneurysms) is 5%. On the contrary mortality rate for emergency surgical intervention is about 70% [1]. Selection of candidates to surgery is still based on measurement of aortic diameter, with a threshold size of 55 mm. The rate of AAA rupture increases from 21% to 46% for diameters between 50 and 70 mm. The main diagnostic tool currently adopted is the CT that allows for obtaining precise information regarding the dimensions and the morphology of the aneurysm and possible proximal extension (juxarenal, infrarenal, thorac-abdominal) and distal (iliac and hypogastric) of the aneurysm, intramural thrombus. Since rupture occurs when the aneurysm wall fails to withstand the forces acting on it, in vivo data on AAA wall pathology could identify patients at risk of rupture. End-stage aneurysm disease and especially aneurysm rupture are characterized by extensive inflammation of the arterial wall. Although the stimulus for this enhanced infiltration is not known, recent insights into the pathophysiology of aneurysm formation, growth, and rupture indicate a close relationship between increased mechanical stress and the activation of infiltrated lymphocytes and macrophages [2]. This increased inflammatory activity results in the progressive breakdown of the aortic wall, aneurysm dilatation and, ultimately, rupture. A further complication is represented by the mechanical actions exerted on the arterial wall by the internal blood flow. The blood flow is strongly influenced by the presence of an AAA, which modifies significantly the geometry of the aorta. Shear stresses and pressure are important factors to understand the formation and evolution of an AAA. Another important aspect is related to the formation of the thrombus that is thought to be relevant for the wall degeneration, see [3] for a comprehensive review of these topics.

This content is only available via PDF.
You do not currently have access to this content.