An abdominal aortic aneurysm (AAA), sometimes called a triple A (AAA), is a dilatation or bulge of the abdominal aorta, the major vessel running behind the abdomen towards the legs. An aneurysm is due to a weakening of the wall of the blood vessel and can be dangerous as the wall may give way leading to catastrophic bleeding (rupture). Rupture of the aneurysm is very uncommon if the dilatation is minor, but the risk increases as the aneurysm gets bigger. Most patients who suffer a ruptured AAA die from the rupture. AAA are much more common in men, smokers, those with high blood pressure, those who have a family history of AAA and those with arterial disease at other sites e.g. previous heart attacks or strokes.
An AAA is usually detected incidentally on a scan (ultrasound or CT) as they rarely cause symptoms until they rupture. If they do cause symptoms before they rupture, they may cause back or abdominal pain. There are two ways in which AAA are repaired, the aim being to reduce the risk of rupture. The traditional operation, or open repair, is a major vascular operation with many potential complications. It is performed by a large incision on the abdominal wall and replacing the diseased artery with a graft (as above). A newer technique to repair aneurysms is called endovascular aneurysm repair. This is performed through small incisions in the groin and involves relining the artery from the inside with a stent graft. This procedure also has risks but these seem to be greatly reduced when compared to the traditional open operation. But not everyone is suitable for the newer endovascular repair. This is decided on the results of a CT scan.
Because both operations have risks, the risk of each aneurysm bursting and the risks of each operation need to be carefully balanced. Generally speaking, an aneurysm less than 5.5cm in maximum diameter is very unlikely to rupture and patients with an aneurysm of less than 5.5cm can be reassured and followed up with further ultrasound scans to monitor if there is a change in size.
If you have an AAA, it is very important that you stop smoking as if you continue to smoke there is an increased risk of the aneurysm increasing in size and bursting. You should also make sure your blood pressure is well controlled and that you are taking a medication usually used to reduce blood cholesterol levels (statins e.g. simvastatin (Lipitor)).
For patients who would like more information see the Patient leaflet for AAA. For medical students and doctors, the AAA PDF contains much more information on AAA and their treatment.
If you think you might have an AAA, see your GP who can arrange for you to have an ultrasound scan. If you do have an AAA, asked your GP or medical specialist to refer you to Mr. Stuart Walker (see contact details).