A VIEW OF ATHEROSCLEROTIC AND NON-ATHEROSCLEROTIC ABDOMINAL AORTIC ANEURYSMS

Resumo

The abdominal aortic aneurysm (AAA) is the most common type of aneurysm, with a significant prevalence in the elderly population. Currently, there is a reasonable amount of evidence that one of the fundamental components for an aneurysm to develop is the destruction of elastic sheets and fibers. Unlike what occurs in the ascending aorta, in most abdominal aortic aneurysms, this elastolysis results from infiltration by mononuclear inflammatory cells, which are sources of enzymes that act on the elastogenic component, such as elastase, metalloproteinases, serine proteinases and cathepsins. Thus, the most frequent type of AAA is that of an atherosclerotic origin – the abdominal portion of the aorta is the most affected by atherosclerosis; however, only a minority of people with severe aortic atherosclerosis develop aneurysms – those whose aorta bears a significant inflammatory component. Besides the atherosclerotic type, other aneurysms are also affected by substantial inflammation, approximately half of these related to the presence of IgG4. This specific type of aneurysm has a peculiar pathophysiological aspect and different clinical and epidemiological characteristics when compared to classic atherosclerotic aneurysm. Therefore, assuming that these aneurysms are rarely studied, the aim of this review was to elucidate the distinct types of AAA, emphasizing their differences in terms of pathophysiology and clinical aspects, which could optimize the differential diagnosis and treatment of AAA in the medical practice.