Treating abdominal aortic aneurysms in England: do we have it right?

Posted: 28/11/2016

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A study in the New England Journal of Medicine has shown that the rate of deaths from a ruptured abdominal aortic aneurysm (AAA) is three times higher in England compared with the rate in the US.  This is despite the introduction in England, in 2009, of screening for men over 65 – the group most affected by AAA.

An AAA is a swelling or ballooning of the abdominal aorta.  The aorta is the largest blood vessel in the body; it carries blood from the heart, down through the chest and the abdomen.  An aneurysm happens when a section of the wall of the aorta becomes weaker than the surrounding tissue.  As the blood inside the aorta is under pressure, the wall of the aorta begins to swell outwards, causing an aneurysm to form. 

The abdominal aorta is usually around 2 cm in diameter.  An aneurysm is said to have developed when a section of the aorta reaches 3 cm or more.  Aneurysms vary in size but they tend to become larger over time.  International guidelines suggest that surgery should be considered once an aneurysm grows to 5.5 cm in diameter for men and 5 cm for women.  

AAAs often cause no symptoms so most people who develop an AAA have no idea they have one.  However, a burst AAA is a medical emergency as the patient is having a massive internal bleed.  Around eight out of ten people with a ruptured AAA either do not survive before they reach hospital or do not survive the subsequent surgery.

In 2009, the Government introduced an AAA screening programme for men over 65.  (From 2013, the programme was offered throughout the UK.)  The screening involves a simple, pain-free, ultrasound of the abdominal area which identifies whether an AAA has developed.  If a small AAA is found, it will then be regularly monitored.  If a large AAA is found, then surgery is likely to be on the cards.

The new study compared three statistics in England and in the US: the rates of aneurysm rupture and aneurysm-related death; the frequency of aneurysm repair and the diameter of aneurysms at surgery.  The study found that, in 2012, on average, the death rate from abdominal aortic aneurysms was more than three and a half times higher in England than in the US.

Furthermore, in England in 2012, the rate of intact AAA repair (that is, where a patient underwent surgery before their aneurysm had burst) was half that of the US and, in England, the aneurysms had reached a larger size by the time surgery was performed.

These statistics have raised concern that surgeons in England may be waiting longer than their American counterparts before performing surgery to prevent AAA rupture.  According to Matt Brown, Professor of Vascular Surgery at the University of Leicester, who was quoted on the BBC website, although the findings ‘do not support an immediate change in clinical practice’, they ‘do suggest that more research is needed to explain the variation in aneurysm death rates between the US and the UK’.

Camilla Wonnacott, an associate in the clinical negligence team at Penningtons Manches LLP, said: “It is important to bear in mind that the risk of developing an AAA increases if you smoke, have high blood pressure or have a sibling or a parent who has or had the same condition.  The opportunity for men over 65 to have AAA screening is obviously very welcome.  It is also possible to identify an AAA when, for example, a patient is given a chest x-ray.  However, aneurysms can be overlooked.  Unfortunately, we do act for individuals and their families where a radiographer or a treating consultant has missed an opportunity to treat an AAA, often with disastrous consequences.  If you or your family has experienced this type of injury, we are always happy to speak to you.”

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