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Key Concepts

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  • Epidemiology

    • Aortic aneurysms were the 15th most common cause of death in the United States in the year 2000. Among patients who die of thoracic aortic aneurysms (TAAs), rupture is the cause of death in about 80 percent of cases. Approximately 50 percent of thoracic aneurysms involve the root and the ascending aorta. The estimated growth rate for TAAs has been calculated to be 1.2 to 4.2 mm/year. Aneurysms that are larger than 6 cm can be associated with a yearly rate of rupture or dissection of at least 6.9 percent and a death rate of 11.8 percent.

  • Pathophysiology

    • 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.

  • Clinical features

    • Most patients with aortic root pathology are asymptomatic, with the exception of patients who present with endocarditis (sepsis, congestive heart failure) or aortic root destruction secondary to acute type A aortic dissection (severe chest pains, asymmetric pulses, congestive heart failure). The age range of presentation is very broad (twenties to eighties) and is dependent on the underlying pathology. Certain patients will have characteristic stigmata of connective tissue diseases such as Marfan syndrome.

  • Diagnostics

    • The workup for candidates for aortic root replacement includes echocardiography to estimate ventricular function and assess for the possibility of aortic valve preservation. Coronary catheterization is usually necessary to rule out coronary artery disease. Thin-slice computed tomography (CT) or magnetic resonance imaging (MRI) scanning will provide the necessary information about the anatomy of the aneurysm. A careful oral examination or dental consultation is very important to prevent postoperative prosthetic valve infection.

  • Treatment

    • Aortic root replacement options include composite valve-graft, separate valve-graft, xenograft tissue, homograft, pulmonary autograft (Ross procedure), and valve-sparing aortic root replacement. The decision to use each one of these options is dependent on patient age and valve preference, comorbid conditions, the condition of the native aortic valve, and contraindications to the use of anticoagulants.

  • Outcomes

    • Operative (30-day) mortality runs ...

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