Abdominal Aortic Aneurism

Risk factors and epidemiology
Abdominal aortic aneurism (AAA) is a focal dilation of the abdominal aorta. Most commonly it occurs between the renal and inferior mesenteric arteries. The incidence of AAA increases dramatically with age. Other risk factors for AAA include: smoking, being a male, history of atherosclerosis, hypertension and a family history of AAA. Inflammation plays an important role in AAA development.

Symptoms
Most patients with AAA are asymptomatic. Symptoms, if present, usually include abdominal and back pain. Symptomatic aneurisms are at a higher risk of rupture.

Ruptured AAA is a surgical emergency. Aneurism rupture can cause rapid exsanguination and shock.

Diagnosis
The diagnosis of AAA is usually made by CT scan of the abdomen. Aneurism can also be detected by MRI and the Ultrasound.

Treatment
The treatment and monitoring of AAA typically depends on the size of the aneurism:

Aneurysms 4.0 to 5.4 cm in diameter should be monitored by ultrasound or CT every 6 to 12 months.

Aneurysms 3.0 to 4.0 cm in diameter should be monitored by ultrasound every two to three years.

Medical therapy consists of blood pressure control and risk factors modification.

Surgery is indicated if the size of the aneurism is twice the size of the adjacent aorta. Symptomatic patients are offered surgery regardless of the size. Rapid aneurism expansion (>0.5cm in 6 mo) and the location of the aneurism are also considered when making decision on surgical treatment.