Annuloaortic ectasia is a term used to describe an increase in diameter of the aortic annulus coupled with an increase in the diameter of the aortic root. This type of situation is seen in patients with Marfan syndrome, Ehlers–Danlos syndrome, Loeys–Deitz syndrome, osteogenesis imperfecta, and pseudoxanthoma elasticum. Annuloaortic ectasia may have familial origins or may be idiopathic. Recently, a significant body of research has focused on the involvement of endogenous extracellular matrix-degrading enzymes in aneurysms and aortic remodeling. Of greatest interest are the matrix metalloproteinases (MMPs), particularly those of the gelatinase class (MMP-2, MMP-9). Similarly ARB2 receptor blockade with Losartan has shown to slow the dilatation of aorta in animal model studies. Another important cause of aortic root destruction is acute infective endocarditis with aggressive organisms such as Staphylococcus aureus. A central common theme in the development of aortic root aneurysms is cystic medial degeneration, in which gradual disruption of the media of the aorta occurs, with the creation of small acellular spaces within it. This process weakens the aortic wall, and a slow remodeling of the aortic root and ascending aorta results in aneurysm formation.