Aortitis and aortic aneurysm in systemic vasculitis

Abstract

Vasculitis encompasses a heterogeneous group of disorders characterized by inflammation of blood vessels. Inflammation affects vessels of any type and size, and causes a wide range of clinical manifestations, depending on the vascular bed involved. The preferential size of involved vessels and the targeted tissues determine the clinical presentation and serve as key elements for classification (Watts & Scott, 2009). Vasculitis may occur as a primary process or may be secondary to an underlying disease such as infection, malignancy or other systemic autoimmune or chronic inflammatory diseases. Blood vessel inflammation results in abnormal vascular remodelling with the potential of severe clinical consequences. In some instances, inflammation leads to intimal hyperplasia resulting in vascular stenoses and ischemia of the tributary tissues. In other settings, inflammation causes disruption of the vessel wall architecture leading to aneurysm formation and eventual dissection or rupture. Aortitis is the term used to define inflammation of one or more layers of the aortic wall and may have an infectious or non-infectious origin (Gornik & Creager, 2008). Non-infectious aortitis is usually part of the spectrum of vascular involvement occurring in primary largevessel vasculitis including giant-cell arteritis (GCA) of the elderly and Takayasu’s arteritis (TAK). Aortitis is a major component of these diseases and may lead to severe complications including aortic aneurysm, dissection or stenosis. Aortitis may also present as a circumscribed condition named isolated aortitis. This term refers to aortitis incidentally found at the time of histopathological examination of aortas obtained from necropsy studies or from patients who have undergone surgical repair of aortic aneurysm or aortic valve replacement. Existing studies are retrospective and most patients have not been prospectively and systematically evaluated in search for a systemic vasculitis or other chronic inflammatory diseases. There is some controversy about whether isolated aortitis is a specific condition or represents an incomplete view of a systemic disease. Occasionally, aortitis may occur in the setting of other primary systemic vasculitis, particularly antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (Chirinos et al., 2004; Lee et al., 2008), and other autoimmune disorders or chronic inflammatory diseases (i.e. sarcoidosis, Crohn’s disease, ankylosing spondylitis, Behcet’s disease, Cogan’s disease, and IgG4-related disease) (Domenech et al., 2005; Gluth et al., 2006; Palazzi et al.,