ELN and atherosclerosis: The demographics and histories of patients with AAD from the International Registry of Acute Aortic Dissection demonstrate that patients with type B AAD were older and had a higher prevalence of atherosclerosis.[34] Elastin is one of the main structural components of the media layer of the arterial wall, and mechanical or functional failure of elastin can predispose the aorta to dissection and degeneration with aneurysm formation.