Microscopic

The two most important features in the walls of atherosclerotic aneurysms are:

• smooth muscle atrophy
• loss of elastic laminae

The adventitia is compressed and is often the site of a lymphocytic infiltrate which may be a response to the presence in the lesion of oxidised lipid or 'ceroid'.

AAA has a familial pattern with a prominent genetic component. For reasons that are unclear, in population based studies, diabetics have a lower incidence of aneurysms than non diabetics (1).

Reference:

• (1) British Heart Foundation (Factfile 2/2008). Abdominal aortic aneurysms.