Abdominal aortic aneurysm (AAA) repair: open surgery, EVAR and when it is advised

The aorta is the main artery that carries blood from the heart. Where it runs through the abdomen it is usually about 2cm wide, which the British Heart Foundation compares to the width of a garden hose. An abdominal aortic aneurysm, often shortened to AAA, is a swelling or balloon-like bulge in that part of the artery.

The NHS explains that most aneurysms do not cause problems, and many people only find out they have one during screening or tests for something else. The concern is that a swollen artery wall is weaker, so there is a risk that it could burst (rupture), which is life threatening. Repair is about reducing that risk before it happens.

Risk factors listed by the NHS include being male and 65 or over, smoking or having smoked, high blood pressure, high cholesterol, a close relative who has had an aneurysm, coronary or peripheral artery disease, COPD, and conditions such as Marfan syndrome. The cause is not always clear.

The main test is an ultrasound scan of the tummy. The NHS says a small handheld probe is placed on the tummy, and you are usually told at the end whether there is an aneurysm and how big it is. An ultrasound is offered to all men when they turn 65, and the NHS screening page says the scan takes around 10 to 15 minutes and is painless.

Aneurysms are also picked up by chance during CT, MRI or ultrasound scans arranged for other reasons, as the British Heart Foundation notes.

The result sorts people into three broad groups. For a small aneurysm, the NHS screening programme arranges a scan every year; for a medium one, every 3 months; and for a large one of 5.5cm or more, referral to a vascular surgeon for more tests and possible treatment. A specialist nurse will talk through medicines, blood pressure checks and ways to slow growth, such as stopping smoking, losing weight if needed and eating a balanced diet.

The NHS says treatment depends mainly on how big the aneurysm is and whether you have symptoms. Surgery may be done if the aneurysm is large (5.5cm or bigger), growing quickly or painful. Small aneurysms are managed with lifestyle changes, blood pressure and cholesterol medicines and regular scans.

NICE guideline NG156 sets out more detail for adults. It says repair should be considered for an unruptured aneurysm if it is symptomatic, if it is larger than 4.0cm and has grown by more than 1cm in a year, or if it is 5.5cm or larger without symptoms. It also says people with an aneurysm of 5.5cm or more should be seen by a regional vascular service within 2 weeks of diagnosis, and those with 3.0cm to 5.4cm within 12 weeks.

The decision is not purely about size. NICE says it should be made jointly by the person and their clinician, taking into account the size and shape of the aneurysm, age, life expectancy, fitness for surgery and other conditions, the risk of rupture without repair, and the benefits and disadvantages of repair, such as time in hospital, risks of the operation, recovery, the possibility of further procedures and the need for follow-up scans.

Where it helps the discussion, NICE suggests that cardiopulmonary exercise testing can be considered when assessing someone for planned repair. It also notes there is uncertainty in the risk estimates for aneurysms larger than 5.5cm, which is one reason the conversation is individual.

The British Heart Foundation describes the two main operations. Endovascular aneurysm repair (EVAR) is a type of keyhole surgery in which a stent-graft, a small metal tube covered with a mesh, is placed inside the abdominal aorta through a small cut in each groin. Open surgical repair involves an operation on the abdomen in which the affected part of the aorta is replaced with a plastic tube, called a graft.

NICE guideline NG156 says to offer open surgical repair to people with an unruptured aneurysm who meet the criteria for repair, unless it is contraindicated because of abdominal copathology, anaesthetic risks or medical conditions. It says to consider EVAR for people with an abdominal copathology such as a hostile abdomen, a horseshoe kidney or a stoma, or other considerations discussed with the person that make EVAR the preferred option.

For people whose anaesthetic risks or other conditions rule out open surgery, NICE says to consider EVAR or conservative management, which means monitoring rather than operating. It also covers complex EVAR, used when the shape of the aneurysm is not suited to a standard stent-graft, and advises that this is only considered when risks and uncertainties compared with open repair have been discussed.

The British Heart Foundation observes that EVAR is a simpler and safer procedure than open surgery in the short term but is not suitable for everyone, and that your surgeon will discuss your options. NICE lists the need for surveillance imaging appointments as one of the factors the person should weigh when deciding.

After EVAR, the BHF says most people can get up and walk around the next day and go home in 2 or 3 days. After open surgery, most people stay for over a week and it can take some weeks to recover fully. Your surgical team will give specific advice on lifting, driving and returning to work.

Lifestyle measures remain important after repair. The NHS recommends stopping smoking, eating healthily, exercising regularly, losing weight if overweight and cutting down on alcohol, and medicines to lower blood pressure and cholesterol may be advised. NICE recommends referral to a stop smoking service for people with an aneurysm who smoke.

Follow-up scans are a recognised part of care. The NHS says aneurysms often get bigger over time and you will usually need regular scans, and NICE lists the need for surveillance imaging appointments among the factors to weigh when choosing repair. Your team will explain what applies after your own operation.

The NHS says to call 999 if you or someone else has sudden, severe pain in the tummy or back, is struggling to breathe or has stopped breathing, has pale or grey skin (on brown or black skin this may be easier to see on the palms of the hands or soles of the feet), or loses consciousness. These could be signs of an aneurysm bursting, which is a life-threatening emergency that needs treatment in hospital as soon as possible.

Less dramatic symptoms still deserve attention. The NHS advises seeing a GP if you have tummy or back pain that does not go away or keeps coming back, or if you feel a lump in your tummy, while noting these have many other causes. If an aneurysm ruptures, emergency surgery is needed. NICE says that people with a suspected ruptured or symptomatic aneurysm accepted by a regional vascular service should leave the referring hospital within 30 minutes of the decision to transfer.

On the NHS, most aneurysms are found through screening at 65 for men or on a scan done for another reason, and repair is carried out by regional vascular services. NICE expects referral to those services within set times once an aneurysm reaches certain sizes.

Private vascular surgeons and hospitals can also assess and repair aneurysms. For a condition where the choice between EVAR and open surgery turns on anatomy and fitness, the most useful question under either route is which operation is proposed and why, how often the team performs it, and what scans will follow. Many people ask for a second opinion at a regional vascular centre if they feel unsure.