Ascending and Arch Aorta

Aortic aneurysms are the 13th-leading cause of mortality in the United States.1 The incidence of thoracic aortic aneurysms (TAA) is increasing with improvements in screening, as well as advances in imaging.2 Replacement of the ascending aorta accounts for the majority of thoracic aortic procedures. TAAs are more frequently present in men and typically occur in the 50- to 70-year age range.3 Disease processes affecting the ascending and arch aorta include degenerative aneurysms and aneurysms associated with connective tissue disease, as well as acute aortic dissection and its variants of intramural hematoma and penetrating ulcer. Syphilitic aneurysms, once the predominant cause of ascending aneurysms, are exceedingly rare today. In the present review, we will discuss these pathological conditions as well as operative techniques and outcomes after medical and operative therapy. Degenerative AneurysmsDegenerative aneurysms comprise the majority of those seen in the ascending aorta and have a specific pathological profile.3 Whereas the elastin content in the ascending aorta is high, that seen in ascending aortic aneurysms is significantly reduced. In addition, the media of the aneurysm displays a loss of smooth muscle cells and fragmentation of the elastic fibers from a process known as cystic medial degeneration. Although this process is seen normally as a consequence of aging, it is accelerated in some and results in the phenotypic expression of an ascending aortic aneurysm. Recent studies have focused on differences in ascending aneurysm pathogenesis for patients with bicuspid and tricuspid aortic valves, with the former suggested as a more-aggressive variant.4 Marfan SyndromeMarfan syndrome is the most common inherited connective tissue disease, with an incidence of 1 in 10 000.5 The basic genetic defect is a mutation of the gene for fibrillin-1, an essential protein of microfibrils. The phenotypic manifestation is that of disorganized elastic fibers, premature cystic medial …