Thoracic and Thoracoabdominal Aneurysms: Etiology, Epidemiology, and Natural History.

Thoracic aortic aneurysms and thoracoabdominal aneurysms are often found incidentally. Complications include dissection or rupture. Most of the thoracic aortic aneurysms and thoracoabdominal aneurysms develop in patients with risk factors for atherosclerosis. Younger patients without significant cardiovascular risk factors may have a genetic basis and include syndromes such as Marfan, Ehlers-Danlos, and Loeys-Dietz and bicuspid aortic valve. Most thoracic aneurysms grow slowly over time and factors that accelerate growth rate include dissection, aneurysm size, bicuspid valve disease, and Marfan syndrome. Size cutoffs where complications occur determine when surgery or intervention should be considered.