Histopathologic differences partially distinguish syndromic aortic diseases

A variety of syndromic diseases such as Marfan syndrome, Loeys-Dietz syndrome, and bicuspid aortic valve with aneurysm along with risk factors of smoking and hypertension result in ascending aortic aneurysms and dissections. Historically, a complicated variety of terms have been used to describe a range of histopathologies that are present in resected specimens. As a result, no consistent patterns of histopathology have been reported. We used the recent Society for Cardiovascular Pathology/Association for European Cardiovascular Pathology consensus statement on nomenclature and diagnostic criteria for noninflammatory aortic disease to blindly evaluate 148 surgically resected specimens. We found that overall patterns of histopathologic changes could separately cluster bicuspid aortic valve and nonsyndromic subjects from Marfan and Loeys-Dietz subjects. Marfan syndrome cases significantly had more overall medial degeneration and mucoid extracellular matrix accumulation than other syndromes. Smooth muscle cell nuclei loss was a feature of aging and not a feature of Marfan or Loeys-Dietz syndrome subjects. We conclude that a consistent use of histologic and histopathologic descriptors can help discriminate different etiologies of ascending aortic aneurysms.