The Determining the Role of Endothelium and Extracellular Matrix in Thoracic Aortic Aneurysm

The aim of this study was to investigate the pathophysiological origin of thoracic aortic aneurysms from a morphological point of view. Thoracic aneurysms are more common in the ascending aorta and arch, with 60% occurring there, and 40% in the descending aorta, albeit the etiological reasons are distinct for each region. While factors such as atherosclerosis, bicuspid aortic valve, familial thoracic aortic aneurysm syndrome, Turner syndrome, Marfan syndrome, aortic arteritis in Takayasu's arteritis, trauma, and dissection can cause thoracic aortic aneurysms, the structural changes of the basement membrane and the exact causes of the mechanism are unknown. A total of 12 patients with thoracic aortic aneurysms with contraindications to interventional therapy underwent surgery was carried out between 2007 and 2017. Transesophageal echocardiography and multi-detector row CT with three-dimensional (3D) reformation in 3 mm slices were performed on all patients. There is partial desquamation of the endothelium, substantial changes of the collagen fibres and basal membrane, and repair attempts in the form of endothelial islets and deep fibre tears, as well as cancellation and destruction of the helical structure of collagen fibres. We discovered severe structural alterations in collagen fibers, endothelium, and basement membrane in thoracic aortic aneurysms, which are identical to acquired aortic valve degeneration.