Contents & Chapter 1

Chapter 2

Chapter 3

Chapter 4

Chapter 5

Chapter 6

Chapter 7

Chapter 8

Chapter 9

Further Information

 

Understanding

Aortic Aneurysms

By Professor Bruce Campbell

IMPORTANT NOTICE
This information is intended not as a substitute for personal medical advice but as a supplement to that advice for the patient who wishes to understand more about his or her condition.
Before taking any form of treatment YOU SHOULD ALWAYS CONSULT YOUR MEDICAL PRACTITIONER.
In particular (without limit) you should note that advances in medical science occur rapidly and some of the information about drugs and treatment may very soon be out of date.
 

About the author

Professor Bruce Campbell is a consultant vascular surgeon in Exeter, where he has been treating patients with aortic aneurysms for over 20 years. As well as his experience in advising and operating on patients with aneurysms, both by conventional surgery and with specialist colleagues by stent grafting, he has published on the challenges posed by decisions about treating aortic aneurysms and about the preferences of patients for different kinds of treatment.

Contents

What are aneurysms and what problems can they cause?

Who gets aneurysms and how can they be prevented?

How are aneurysms diagnosed and investigated?

Open operations for aortic aneurysms

Endovascular aneurysm repair

What problems can occur after treatment of aneurysms?

Ruptured (leaking) aortic aneurysms

‘Acute’ aortic aneurysms and mortality and survival statistics

Screening for abdominal aortic aneurysms

Further Information

What are aneurysms and what problems can they cause?

What is the aorta?

The aorta is the artery that takes blood from your heart to the rest of your body. In the chest it gives off branches to your arms (the subclavian arteries) and your head (the carotid arteries). It runs down just in front of your spine, through the diaphragm into the abdomen. There it gives off branches to your liver, gut and kidneys. It ends by dividing into two branches – to your right and left legs (the iliac arteries).
Blood is pumped by the heart into the aorta and reaches all parts of your body through progressively smaller branch arteries. The ‘blood pressure’ refers to the pressure in the arteries which pushes the blood forward. Blood reaches all the cells of your body through tiny vessels called capillaries. It then returns to your heart through the veins, picking up oxygen on its way through the lungs.

What is an aneurysm?

An aneurysm means ballooning of an artery, caused by weakening of its wall. The pressure of the blood inside the artery causes the weakened section of artery wall to ‘balloon’.
Aneurysms are most often found in the aorta at the back of the abdomen (in front of the spine). Occasionally aneurysms can occur in other parts of the aorta, or in other arteries, but the abdominal aorta is the most common place.
Having an aneurysm usually causes no symptoms at all, so most people with aortic aneurysms have no reason to suspect that they have a problem. As they occur right at the back of the abdomen, aortic aneurysms are difficult to feel.

 

Abdominal aortic aneurysms are commonly abbreviated in medical writing to ‘AAA’ and some doctors refer to them as a ‘triple A’.
The big risk of aneurysms is that they can leak or burst and, without treatment, this is fatal because of bleeding from the aorta into the surrounding tissues. It is quite a common reason for the sudden death of men aged over 65.
However, people have aneurysms for many years without them ever causing a problem. Deciding whether and how best to treat an aortic aneurysm to prevent it leaking can therefore be difficult, because the treatment of aneurysms also has risks.

What causes an aortic aneurysm?

The precise reason for most aortic aneurysms is not known. Increasing age is a factor, as is being male: most aortic aneurysms occur in men over the age of about 65. There is some tendency for them to run in families. Smoking, high blood pressure and high blood cholesterol increase the risk.

How common are aortic aneurysms?

Aortic aneurysms are present in about 5 per cent (1 in 20) men aged over 65, but many of them remain small and never reach a size that is likely to cause harm. They are about five times less common in women.

The size of the aorta

The normal abdominal aorta is usually about 2–2.5 centimetres (cm) wide (about one inch). The size varies depending on the individual – the aorta of a small woman is narrower (e.g. 1.5 cm) than the aorta of a big man (e.g. 2.5 cm).
If the diameter (width) of the abdominal aorta is greater than 3 cm then it is said to be aneurysmal, but at that size there is no danger of the aorta leaking. Another medical word sometimes used for an aorta that is abnormally wide, but not greatly ballooned, is ‘ectatic’.
If the aorta enlarges to a width of 5 to 6 cm then leakage or rupture starts to become a risk. At a diameter of 6 cm there is a risk of about 30 per cent of rupture over the next 3 years (but, conversely a 70 per cent chance that a 6 cm aneurysm will not rupture within 3 years). Some aortic aneurysms are discovered at very large sizes (for example, 10 cm diameter or more), never having caused symptoms.
It is hard to predict whether an aortic aneurysm will grow and at what rate. On average, aneurysms increase in width by about two to three millimetres per year, but some stop enlarging and never reach a size at which treatment needs to be considered.

How can aortic aneurysms be treated?

There are two kinds of operation for aortic aneurysms, both of which place tube-shaped grafts of material inside the aneurysm, through which the blood then flows: open operations and EVAR. Open operations involve stitching the bypass graft to the aorta above and below the aneurysm, via a major abdominal surgery. Stent grafts (endovascular aneurysm repair – EVAR) are placed inside the aneurysm through incisions in the groins using X-ray guidance. The type of operation that is possible is determined by the shape of the aorta and the arteries above and below it. Open operations are possible for all kinds of aortic aneurysms but stent grafts are not always possible.

Open operations

The traditional operation involves major surgery under a general anaesthetic through a long incision in the abdomen (an ‘open operation’). The aorta is clamped above and below the aneurysm to stop the blood flow. The aneurysm is opened and a bypass graft is stitched in place, to carry blood from the aorta above the aneurysm to the aorta (or its main branches) below the aneurysm. This kind of major surgery poses greater immediate risks and has a longer recovery period than necessary for stent grafts, but it may be the only treatment possible for some aneurysms. In addition the long-term results are known to be very good and no further checks are necessary.

Endovascular aneurysm repair

It is now possible to treat many aneurysms by inserting a specially sized and packaged ‘stent graft’ using a smaller operation in which the abdomen is not opened. This is sometimes called endovascular aneurysm repair (EVAR). It is done with the aid of X-ray pictures to manoeuvre the stent graft into position and to check the final result. EVAR may be done under general, spinal or local anaesthetic. Recovery is quicker than after conventional surgery and the risk of immediate serious complications is lower. However, it is not known how often stent grafts will develop problems over the years and regular checks are necessary with scans and/or X rays.
Scans will show if EVAR is possible: the aneurysm and nearby arteries need to be a suitable shape and size for a stent graft to be inserted. If they are not, the only choice is a traditional open operation. The decision about whether to treat an aortic aneurysm by surgery always needs careful and individual consideration.

Decisions about treatment

Open operations for aortic aneurysms involve major surgery, with some risk to life and the possibility of serious complications, but they provide a good and permanent repair of the aneurysm.
Stent grafts (EVAR operations) have less chance of causing serious problems, but do need to be checked by scans in the long term, and occasionally they need further procedures to repair ‘endoleaks’ (blood leaking into the aneurysm sac around the stent graft).

Elective, acute (urgent) and leaking (ruptured) abdominal artery aneurysms

Elective surgery

An elective operation for an aortic aneurysm means one that is done at a planned time for an aneurysm that is not causing any severe or acute symptoms. This kind of treatment has relatively low risks of serious complications or death. The medical term for an aneurysm treated in this way is ‘an elective aneurysm’.

Leaking (ruptured) aortic aneurysms

If an aortic aneurysm leaks an emergency operation is often possible, although people whose aneurysms leak often die without ever reaching hospital. This is complex surgery with a significant chance of major complications. Many patients do not survive, even after technically successful operations. ‘Ruptured’ means ‘burst’ and suggests a more serious situation than a ‘leak’ but the two words are often used interchangeably.

Acute (urgent) aortic aneurysms

Sometimes patients have emergency operations for aortic aneurysms that have caused sudden pain, suggesting a leak, but which are found at surgery not to have leaked. These are called ‘acute aortic aneurysms’. They may have expanded suddenly, so causing pain, but often the cause for the acute pain is not clear.

Other aneurysms

Aortic aneurysms can occur in the chest, but these are less common than abdominal aortic aneurysms. Other arteries can also become aneurysmal. These are described in the section ‘Special kinds of aortic aneurysm and aneurysms of other arteries’.

Key points

• The normal aorta in the abdomen is less than 3 cm wide; it becomes wider it is called an abdominal aortic aneurysm (AAA)

• Some small aortic aneurysms never grow to a larger size; if they grow to 5 to 6 cm or more in width there is a risk that they may leak or rupture

• Rupture of an aortic aneurysm causes death, often very quickly.

• Sometimes ruptured aneurysms can be treated by major surgery, but this is not always successful at saving life

• Most aortic aneurysms do not cause symptoms, but if they are large they are often treated to prevent rupture

• The pros and cons of surgery always need to be considered very carefully for each individual