From the Guidelines
Pathophysiology of Abdominal Aortic Aneurysm (AAA)
The pathophysiology of an abdominal aortic aneurysm (AAA) is primarily characterized by inflammatory, proteolytic, and neovascular changes that lead to the loss of elastin and accumulation of fibrous material in the arterial wall 1.
- These changes result in a segmental, full-thickness dilation of the aorta with a maximal diameter >1.5 times larger than the adjacent normal segment, typically affecting the infrarenal abdominal aorta 1.
- The degenerative and atherosclerotic changes in the aortic wall are the primary causes of AAA, leading to a fusiform morphology in the majority of cases 1.
- Risk factors for AAA include advanced age, male sex, smoking, family history of AAA, hypertension, hypercholesterolemia, peripheral artery disease, and genetic syndromes 1.
- The natural history of AAA is progressive expansion and potential rupture, which is a medical emergency with high mortality 1.
- Aneurysm growth is influenced by factors such as large aneurysm diameter, rapid growth, smoking, hypertension, and high peak wall stress 1.
- Screening and surveillance are crucial for early detection and management of AAA, with a generally accepted threshold of an aneurysm diameter exceeding 5.5 cm in men and 5.0 cm in women for elective surgical repair 1.
From the Research
Pathophysiology of Abdominal Aortic Aneurysm (AAA)
The pathophysiology of AAA is a complex process involving multiple factors, including:
- Aortic wall inflammation 2, 3, 4, 5, 6
- Elastin breakdown 2, 4
- Oxidative stress 2
- Smooth muscle cell (SMC) phenotypic switching and dysfunction 2, 4
- Extracellular matrix degradation 2, 4
- Metallo-proteinases in the degeneration of the aortic wall 5
Risk Factors
The development of AAA is influenced by various risk factors, including:
- Lifestyle factors, such as smoking 2, 4, 5
- Genetic predisposition 2, 4, 5
- Older age 3, 4, 5
- Male sex 4
- Family history of AAA 4, 5
- Hypertension 5
- Dyslipidemia 5
Consequences of AAA
If left untreated, AAA can lead to rupture, resulting in: