What is the main cause of abdominal aortic aneurysm (AAA)?

The primary cause of abdominal aortic aneurysm (AAA) is atherosclerosis. Atherosclerosis is characterized by the build-up of fatty deposits, cholesterol, and other substances in the arterial walls, leading to inflammation, plaque formation, and ultimately vascular wall degeneration. This process weakens the aortic wall, making it more susceptible to dilation and the formation of an aneurysm.

As the aorta weakens, increased pressure from blood flow can exacerbate this condition, leading to further dilation or rupture. While hypertension can contribute to the progression of aortic diseases by causing more strain on the vessel walls, it is often considered a secondary factor in the context of AAA development. Other factors such as diabetes and trauma are not primary causes of AAA; diabetes may affect vascular health, but it does not directly cause aneurysms. Trauma, while it can cause acute injuries to the aorta, does not relate to the development of AAA associated with chronic conditions. Thus, atherosclerosis remains the most significant underlying condition leading to the formation of an abdominal aortic aneurysm.