All about aortic aneurysm

Consultant Vascular Surgeon Rachel Bell explains abdominal and thoracic aortic aneurysms, what causes them and how to get screened.

Thoracic aortic aneurysm and abdominal aortic aneurysm illustration 

What is an aortic aneurysm?

An aneurysm is a blood vessel dilation, where the artery or vein swells to an abnormal size. “As a fully developed adult, your aorta – the main artery in your body – measures about 1.5–2cm in diameter,” explains Rachel Bell, Consultant Vascular Surgeon and clinical lead for vascular surgery at Guy’s and St Thomas’ hospitals in London.

The main risk factors are smoking, a family history of aneurysms, high blood pressure, high cholesterol and diabetes

“An aneurysm usually grows slowly, around 1–2mm per year. Once it reaches a certain size, the risk of it rupturing (bursting) becomes too high and surgery is needed to repair it.” An aneurysm is usually classed as large once it reaches 5.5cm. 

Three-quarters of aortic aneurysms occur in the abdomen (below your kidneys) and this type is relatively common, affecting about 1.5 per cent of men over 65. “If it ruptures, it’s an emergency situation which requires surgery as soon as possible to repair the aorta,” Rachel explains.

A rupture may never occur but if it does, it is fatal in 80 per cent of cases. Ruptured aortic aneurysms cause 5,000 deaths in the UK each year. They are most common in men over 65 - they are responsible for 1 in 75 deaths of men in this age group.

A thoracic aortic aneurysm means it is higher up the aorta, in your chest. These are less common than the aortic kind, but equally dangerous if they rupture.

Aortic aneurysm causes

Aortic aneurysm is unusual at such a young age. “Some people are predisposed to developing an aneurysm because of family history,” says Rachel.

“Others will have been born with a condition that increases their risk, such as coarctation of the aorta – a condition where there is narrowing in part of the aorta.

“The main risk factors are:

“You can reduce your risk by modifying these risk factors, though your genetic risk cannot be altered.”

Symptoms of abdominal aortic aneurysm

In most cases you won't have any symptoms of an aneurysm, so an ultrasound test is the only way to find out if you have one. But if an aneurysm becomes large it can sometimes cause a pulsating feeling in your abdomen, or persistent back pain.

If an aneurysm ruptures, it will cause internal bleeding. This is a medical emergency and you should call 999 immediately if you or someone with you has any of these symptoms:

  • a sudden severe pain in the abdomen, back or lower back area
  • feeling cold, clammy, sweaty, faint and breathless
  • loss of consciousness.

Abdominal aortic aneurysm screening

There is an abdominal aortic aneurysm (AAA) screening programme in place for men aged 65 and over across the UK. Men are six times more likely than women to have an AAA.

There is no screening programme for thoracic aneurysm, which is equally common in men and women, but rarer than abdominal aneurysm and harder to scan for.

“The screening uses simple ultrasound, which is quick and harmless,” Rachel explains. “Abdominal aneurysms can also be found incidentally during investigations for other conditions. When detected, the person will be monitored regularly until the aneurysm reaches a size that indicates surgery will be necessary.

“For both types of aneurysm, repair is either open surgery or a stent graft that can be done using a minimally invasive ‘keyhole’ technique. A stent graft is a tube of metal mesh lined with fabric. The fabric re-lines the aorta and the metal mesh helps support the artery. This is the best option where possible, but isn’t suitable in all cases.”

Men or women under 65 who have a close relative (parent or sibling) who has or has had an AAA are not eligible for screening but are advised to talk to their GP about the possibility of a referral for an ultrasound at their local hospital at an age that is five years younger than when their relative was diagnosed.

All men are invited for screening during the year they turn 65. Men older than 65 who haven’t been screened can self-refer for screening by contacting their local service.

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