Abdominal aortic aneurysm overview
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Abdominal Aortic Aneurysm Microchapters |
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Differentiating Abdominal Aortic Aneurysm from other Diseases |
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Diagnosis |
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Abdominal aortic aneurysm overview On the Web |
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Risk calculators and risk factors for Abdominal aortic aneurysm overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]
Overview
Abdominal aortic aneurysm, also written as AAA and often pronounced 'triple-A', is a localized dilatation of the abdominal aorta, that exceeds the normal diameter of the abdominal aorta by more than 50%.
Definition
The normal diameter of one's aorta depends on the patient's age, sex, height, weight, race, body surface area, and baseline blood pressure. On average, the normal diameter of the infrarenal aorta (where abdominal aortic aneurysms are located) is 2 cm. Therefore an abdominal aortic aneurysm is defined as a dilation of 3.0 cm or more.
An abdominal aortic aneurysm is to be distinguished from aortic ectasia which is defined as a mild generalized dilatation (<50% of the normal diameter of ≤ 2.9 cm) that is due to age-related degenerative changes in vessel wall.
Anatomy
The aorta below the renal arteries, also known as the infrarenal aorta, is the location of 90% of abdominal aortic aneurysms. Other possible locations are suprarenal and pararenal. The aneurysm can extend to include one or both of the iliac arteries.
Classification
Aneurysms are usually classified by their shape:
Fusiform Aneurysms
- Most common type seen in the infrarenal aorta
- Diffuse, circumferential
Saccular Aneurysms
- Involve only a portion of the circumference, with a characteristic outpouching of the vessel wall.
Historical Perspective
The etymology of the word aneurysm comes from the Greek word for "dilatation". Abdominal aortic aneurysm as a medical condition has been recognized since ancient times, but was not been successfully treated until the early part of the 20th century.
Pathophysiology
The underlying pathophysiology of abdominal aortic aneurysm involves genetic influences, smoking, hypertension, hemodynamic influences and underlying atherosclerosis. In rare instances infection, arteritis, and connective tissue disorders may play a role.
Videos on Abdominal Aortic Aneurysm
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References
Acknowledgements
The content on this page was first contributed by: C. Michael Gibson M.S., M.D. Template:WH Template:WS