ABSTRACT
Abdominal aortic aneurysm (AAA), derived from the ancient Greek word aneurysma which describes ‘a widening’, is a pathological enlargement of the abdominal aorta. Whilst aneurysmal change can aect any vessel, they most commonly aect the infrarenal abdominal aorta, to cause an AAA. ese AAAs are most common in men, in whom they are sixfold more prevalent than women, and most commonly above the age of 60 years. e commonest clinical denition of an AAA is based on the diameter of the abdominal aorta, which is considered aneurysmal at a diameter of 3.0 cm or more.1,2 is widely held denition does not take account of individual variation in aortic diameter or take account for gender variation as one would expect on average a female aorta to be comparatively smaller. erefore, some researchers have considered the alternate denition of an aneurysm as an increase of 1.5 times the expected normal diameter, and on radiological assessment, this may be assessed by comparison to the adjacent unaected vessel. An arterial aneurysm may be true when it aects all layers of the arterial wall or false when it does not. e majority of true aneurysms are associated with atherosclerotic (AS)
disease in the vessel wall, but unlike typical AS which tends to stenosis or occlusion of the vessel, in these individuals with an underlying genetic predisposition, it causes the vessel to dilate. Whilst all aneurysm have some degree of chronic inammatory change within the arterial wall, about 10% of aneurysm have pronounced inammatory response extending beyond the wall to involve the surrounding tissues of the retroperitoneum, oen described as ‘inammatory’ aneurysm. Aneurysm growth can be complicated by rupture, with bleeding outside the arterial wall, and this is most oen fatal unless treated by open or endovascular repair. erefore, known small aneurysms should be placed under radiological surveillance and large aneurysms should be considered for active treatment by endovascular or open repair, to prevent fatal rupture. In this chapter, we will discuss the management principles for AAA.
