Abdominal Aortic Aneurysms
- Abdominal aortic aneurysms are much more common than thoracic aortic aneurysms.
- Age is an important risk factor, and the incidence of abdominal aortic aneurysm rises rapidly after the age of 55 years in men and 70 in women.
- The prevalence of abdominal aortic aneurysms is ≈5% among men ≥65 years of age screened by ultrasound.
- Smoking is the risk factor most strongly associated with abdominal aortic aneurysms, followed by age, hypertension, hyperlipidemia, and atherosclerosis. Sex and genetics also influence aneurysm formation.
- Men are 10 times more likely than women to have an abdominal aortic aneurysm of 4 cm or greater.
- Those with a family history of abdominal aortic aneurysm have an increased risk of 30% and their aneurysms tend to occur at a younger age and carry a greater risk of rupture than do sporadic aneurysms.
Thoracic Aortic Aneurysms
- Thoracic aneurysms may involve one or more aortic segments (aortic root, ascending aorta, arch, or descending aorta) and are classified accordingly.
- Sixty percent of thoracic aortic aneurysms involve the aortic root and/or ascending aorta, 40% involve the descending aorta, 10% involve the arch, and 10% involve the thoracoabdominal aorta (with some involving >1 segment).
- The etiology, natural history, and treatment of thoracic aneurysms differ for each of these segments.
