Ultrastructural features of the aortic wall in a patient with Kommerell diverticulum.

We report on the ultrastructural features of the aortic wall in a patient with Kommerell diverticulum. A 70-year-old woman with a right aortic arch, aberrant left subclavian artery, and Kommerell diverticulum underwent a successful total arch replacement plus the frozen elephant trunk procedure with anatomical left subclavian artery reconstruction. Small pieces of the ascending aorta, distal arch, right common carotid artery, and left subclavian artery were investigated ultrastructurally. In the ascending aortic wall, multiple cystic cavities were observed in the subintimal region of the media by scanning electron microscopy. Changes in organelles, including mild dilation of rough-surfaced endoplasmic reticulum and mitochondrial swelling and degrading, were also observed in all specimens by transmission electron microscopy. These ultrastructural features may indicate the fragility or stress of the aortic wall and are useful when considering the early surgical intervention of a patient with Kommerell diverticulum.