An abdominal aortic aneurysm (AAA) is a swelling (aneurysm) of the aorta – the main blood vessel that leads away from the heart, down through the abdomen to the rest of the body.The abdominal aorta is the largest blood vessel in the body and is usually around 2cm wide – roughly the width of a garden hose. However, it can swell to over 5.5cm – what doctors class as a large AAA.
Large aneurysms are rare, but can be very serious. If a large aneurysm bursts, it causes huge internal bleeding and is usually fatal. The bulging occurs when the wall of the aorta weakens. Although what causes this weakness is unclear, smoking and high blood pressure are thought to increase the risk of an aneurysm. AAAs are most common in men aged over 65. A rupture accounts for more than 1 in 50 of all deaths in this group. This is why all men are invited for a screening test when they turn 65. The test involves a simple ultrasound scan, which takes around 10-15 minutes.
An abdominal aortic aneurysm – symptoms
In most cases, an unruptured abdominal aortic aneurysm (AAA) will cause no symptoms, unless it becomes particularly large.
Symptoms of an unruptured AAA may include:
- a pulsating feeling in your stomach (abdomen), usually near your belly button, that’s usually only noticeable when you touch it
- persistent back pain
- persistent abdominal pain
If you have any of the symptoms above, you should see your GP as soon as possible.
If your aortic aneurysm ruptures, you will feel a sudden and severe pain in the middle or side of your abdomen. In men, the pain can also radiate down into the scrotum.
Other symptoms include:
- sweaty and clammy skin
- rapid heartbeat (tachycardia)
- shortness of breath
- feeling faint
- loss of consciousness
A ruptured aortic aneurysm is a medical emergency, and it’s important to get to hospital as soon as possible.
Around 80% of people with a rupture die before they reach hospital or don’t survive emergency surgery.
This is why the NHS AAA Screening Programme was introduced, so dangerously large aneurysms can be treated before they burst.
If you suspect that you or someone in your care has had a ruptured aneurysm, call 999 immediately and ask for an ambulance.
An abdominal aortic aneurysm – causes
The aorta is the largest blood vessel in the body. It transports oxygen-rich blood away from the heart to the rest of the body.
An abdominal aortic aneurysm (AAA) occurs when part of the aorta wall becomes weakened and the large amount of blood that passes through it puts pressure on the weak spot, causing it to bulge outwards to form an aneurysm.
The abdominal aorta is usually around 2cm wide – about the width of a garden hosepipe – but can swell to over 5.5cm, which is what doctors classify as a large aneurysm.
Risk factors for an AAA
It’s not known exactly what causes the aortic wall to weaken, although increasing age and being male are known to be the biggest risk factors.
One study found that people aged over 75 are seven times more likely to be diagnosed with an AAA than people under 55 years old.
Men are around six times more likely to be diagnosed with an AAA than women.
However, there are other risk factors that you can do something about – described below – the most important of which is smoking.
Research has found that smokers are seven times more likely to develop an AAA than people who have never smoked.
The more you smoke, the greater your risk of developing an AAA. People who regularly smoke more than 20 cigarettes a day may have more than 10 times the risk of non-smokers.
The risk may increase because tobacco smoke contains harmful substances that can damage and weaken the wall of the aorta.
Atherosclerosis is a potentially serious condition where arteries become clogged up by fatty deposits, such as cholesterol.
An AAA is thought to develop because these deposits (called plaques) cause the aorta to widen in an attempt to keep blood flowing through it. As it widens, it also gets weaker.
Smoking, eating a high-fat diet and high blood pressure all increase your risk of developing atherosclerosis.
High blood pressure
As well as contributing to atherosclerosis, high blood pressure (hypertension)can place increased pressure on the aorta’s wall.
Having a family history of AAAs means that you have an increased risk of developing one.
One study found that people who had a brother or sister with an AAA were eight times more likely to develop one than people whose siblings were unaffected.
This suggests that certain genes you inherit from your parents may make you more vulnerable to developing an AAA.
However, no specific genes have yet been identified.
An abdominal aortic aneurysm – diagnosis
An abdominal aortic aneurysm (AAA) usually causes no symptoms. Therefore, they tend to be diagnosed as a result of screening, or during a routine physical examination when a GP notices a distinctive pulsating sensation in your abdomen.
A diagnosis can be confirmed using an ultrasound scan. Ultrasound can also determine the size of the aneurysm, which is an important factor in deciding on a course of treatment.
An abdominal aortic aneurysm – treatment
Treatment for an abdominal aortic aneurysm (AAA) depends on several factors, including the aneurysm’s size, your age and general health.
In general, if you have a large aneurysm (5.5cm or larger) you will be advised to have surgery, either to strengthen the swollen section of the aorta or to replace it with a piece of synthetic tubing.
This is because the risk of the aneurysm rupturing is usually greater than the risk of having it repaired.
If you have a small (3.0-4.4cm) or medium (4.5-5.4cm) aneurysm, you will be offered regular scans to check its size.
You will also be given advice on how to slow its growth and reduce the risk of it rupturing – for example, stopping smoking – and perhaps medications to reduce your blood pressure and cholesterol level.
If you have a large AAA
If you are diagnosed with an AAA that is 5.5cm or larger, you will be referred to a vascular surgeon (a surgeon who specialises in diseases of the blood vessels), who may recommend an operation.
The surgeon will discuss treatment options with you, taking into account your general health and fitness, as well as the size of your aneurysm.
If it’s decided that surgery isn’t suitable for you, it’s still possible to reduce the risk of the aneurysm bursting, and you will have regular scans to check its size – in the same way people with small or medium aneurysms are treated.
See below for more information on treating small and medium aneurysms.
There are two surgical techniques used to treat a large aneurysm:
- endovascular surgery
- open surgery
Although both techniques are equally effective at reducing the risk of the aneurysm bursting, each has its own advantages and disadvantages.
The surgeon will discuss with you which is most suitable.
Endovascular surgery is a type of „keyhole” surgery where the surgeon makes small cuts in your groin.
A small piece of tubing called a graft– made of metal mesh lined with fabric – is then guided up through the leg artery, into the swollen section of aorta, and sealed to the wall of the aorta at both ends.
This reinforces the aorta, reducing the risk of it bursting.
This is the safest of the two types of surgery available. Around 98-99% of patients make a full recovery, and recovery time from the operation is shorter than if you have open surgery.
There are also fewer major complications, such as wound infection or deep vein thrombosis (DVT).
However, the way the graft is attached is not as secure as open surgery. You’ll need regular scans to make sure the graft hasn’t slipped, and in some patients, the seal at each end of the graft starts to leak and will need to be resealed. You will need to have surgery again if either of these occurs.
In open surgery, the surgeon cuts into your stomach (abdomen) to reach the abdominal aorta and replaces the enlarged section with a graft.
This type of graft is a tube made of a synthetic material.
Because the graft is stitched (sutured) into place by the surgeon, it’s more likely to stay in place, and will usually work well for the rest of your life.
The risk of complications linked to the graft after surgery is lower than in people who have endovascular surgery.
Open surgery isn’t usually recommended for people who are in poor health as it is a major operation. It is slightly more risky than endovascular surgery, with 93-97% of patients making a full recovery.
The main risk of open surgery is death or heart attack, and recovery time is longer than with endovascular surgery.
There is also a greater risk of complications, such as wound infection, chest infection and DVT.
Making a decision about treatment for a large aneurysm
If you or a relative is faced with making a decision about treatment for a large AAA, the AAA repair decision aid may help you weigh up the pros and cons of each option.
If you have a small or medium AAA
If you are diagnosed with a small (3.0-4.4cm) or medium (4.5-5.4cm) aneurysm, you won’t be referred to see a vascular surgeon, as it’s unlikely you’d benefit from surgery.
You’ll be invited back for regular scans to check the size of the aneurysm, in case it gets bigger – every year if you have a small aneurysm and every three months if you have a medium aneurysm.
You will also be given advice on how to prevent the aneurysm from getting bigger, including:
- stopping smoking
- eating a balanced diet
- ensuring you maintain a healthy weight
- taking regular exercise
If you smoke, the most important change you can make is to quit. Aneurysms have been shown to grow faster in smokers than in non-smokers.
Your GP will be sent your test result and may decide to change your current medication or start you on a new one, especially if you have:
- high blood pressure – which you will probably be treated for with a medication called an angiotensin-converting enzyme (ACE) inhibitor
- high cholesterol – which you will probably be treated for with a medication called a statin
Treating a ruptured AAA
Emergency treatment for a ruptured AAA is based on the same principle as preventative treatment. Grafts are used to repair the ruptured aneurysm.
The decision on whether to perform open or endovascular surgery is made on a case-by-case basis by the surgeon carrying out the operation.
An abdominal aortic aneurysm – prevention
The best way to prevent getting an aneurysm, or reduce the risk of an aneurysm growing bigger and possibly rupturing, is to avoid anything that could damage your blood vessels.
- eating a high-fat diet
- not exercising regularly
- being overweight or obese
If your GP finds out you have high blood pressure or a high cholesterol level, you may be prescribed medication for both. This will reduce the risk of developing an abdominal aortic aneurysm (AAA).
Smoking is a major risk factor for aneurysms because it causes atherosclerosis (hardening of the arteries) and raises your blood pressure.
Tobacco smoke contains substances that can damage the walls of the arteries.
It is known that smokers are seven times more likely than non-smokers to develop an AAA.
The more you smoke, the greater your risk. People who regularly smoke more than 20 cigarettes a day may have more than 10 times the risk of non-smokers.
If you want to stop smoking, your GP will be able to refer you to an NHS Stop Smoking Service, which will give you dedicated help and advice about the best ways to quit.
You can also call or chat online with Quit Your Way Scotland. The specially trained helpline staff can offer you free expert advice and encouragement.
Eating a high-fat diet increases your risk of atherosclerosis.
It’s especially important to limit the amount of foods you eat that are high in saturated fat, such as biscuits, cakes, butter, sausages and bacon.
This is because eating too much saturated fat can lead to high cholesterol, which can build up in the artery walls.
Being active and doing regular exercise lowers blood pressure by keeping your heart and blood vessels in good condition.
Regular exercise can also help you lose weight, which will also help lower your blood pressure.
Adults should do at least 150 minutes (two hours and 30 minutes) of moderate-intensity aerobic activity every week.
Examples of moderate intensity activity include cycling or fast walking.
For it to count, the activity should make you feel warm and slightly out of breath. Someone who is overweight may only have to walk up a slope to get this feeling.
Physical activity can include anything from sport to walking and gardening.
Get more ideas on being active.
Being overweight forces your heart to work harder to pump blood around your body. This can raise your blood pressure, which in turn puts pressure on your arteries.