An Abdominal Aortic Aneurysm (AAA) is a swelling of the aorta that typically starts just below the arteries to the kidneys (approximately at the level of the lower rib cage), and extends down to the bifircation (division) of the aorta (at the level of the umbilicus) and sometimes into the iliac arteries (down towards each groin). Aneurysms occur elsewhere: in the chest (Thoracic Aortic Aneurysms), in the pelvis (Iliac Aneurysms), in the groin (Femoral Aneurysm), behind the knees (Popliteal Aneurysm), etc.

Aneurysms an be treated by open surgery or by minimally invasive endoluminal surgery. Postoperative monitoring is advisable because patients can develop aneurysms elsewhere.

The cause of AAA is not known. However, there are some clear risk factors: 75% are male, over 65 years old, and current or past tobacco smokers. Hypertension is also a significant risk factor.

There is a familial tendency in 10-15% of all patients. This is not a directly inherited disease and the tendency varies from family to family. All first-degree relatives of an affected patient should be screened for AAA. Subsequent elective aortic surgery has a 90%+ success rate but emergency surgery for a leaking, ruptured or thrombosed aneurysm has a 50% success rate; the rate only includes patients who make it to surgery.

Screening involves: Review of vascular risk factors, clinical examination of the abdomen and palpation of the pulses in the legs. The patient then hasS a specialist vascular ultrasound of the abdominal aorto-iliac arteries and lower limb arteries. Surveillance should start at the age of 60 (or 5 years before the affected relative’s age at diagnosis/surgery). Follow up decisions depend mostly on the abdominal aortic diameter:

AA, cm Conclusion Action
2-3cm Normal/near normal aortic diameter US in 5 years, cease at 80-85y.o.(?)
3-4cm Increased diameter US in 12 months
4-5cm Increased diameter, treatment likely, for pre-op workup, pt/family consent & options discussion Refer to Vascular Surgeon (routine appt)
5cm+ AAA for treatment in otherwise well patient Refer to Vascular Surgeon (1-2 week appt)
6cm+ AAA for treatment promptly Refer to Vascular Surgeon (call surgeon)

Diameter enlargements for other arteries are different: Thoracic aorta 6cm, iliac arteries 3cm, Popliteal arteries 2cm. Referral for an opinion is best done early as surgical treatment may be preceded by an extensive medical workup +/- treatment. Surgeons will prefer to organise specialised CT angiography, etc. as time permits.

This information on this page is general in nature and is designed to be sent to AAA/Aneurysm patients of Southern Vascular. Patients should give this information to their relatives to show to their own doctors.