What is an aneurysm ?
The heart pumps blood to the body through arteries, and
sometimes these can become stretched in one or more places due to a
gradual loss of elastic tissue in the artery wall to contain the
blood pressure. This process will lead to a section of the artery
being significantly larger than it should be, which is an
Aneurysms can occur in any artery but are only common in the
abdomen (aortic aneurysm) or behind the knee (popliteal aneurysm).
Occasionally they can occur in the chest (thoracic aortic aneurysm)
and very rarely elsewhere in the body.
Why is it dangerous ?
The vessel wall thins as it stretches and eventually will split
or rupture, leading to sudden internal bleeding. This is usually
catastrophic, and few patients survive.
As the aneurysm grows slowly, it can become lined by clot, and
occasionally this may cause problems with the circulation in the
leg(s). This may be because pieces break off from the aneurysm and
travel into the leg arteries, or because the entire aneurysm clots
off suddenly which prevents blood flowing to the legs. This is more
a feature of aneurysms behind the knee, and is rare in aortic
What are the symptoms ?
There are generally no symptoms during the gradual enlargement,
though you or your doctor may notice an increased pulse or a
swelling at the site of the aneurysm. Although many patients have
their aneurysm detected when they see a doctor about abdominal
pain, it is very seldom the aneurysm that causes it.
When an aneurysm is near rupture, there may be some back or
abdominal discomfort, or tenderness over the aneurysm.
Rupture is accompanied by severe lower back pain, and patients
often collapse or faint due to low blood pressure.
If the circulation to the legs is cut off by clot, the leg
becomes cold, white and painful, then loses feeling and becomes
weak or paralysed. If this is left too long, even successful
treatment of the aneurysm may not save the leg.
Will it need an operation ?
This depends on the size of the blood vessel and your fitness,
particularly the heart and lungs. The risk goes up as the vessel
gets larger, but operating on the circulation is potentially
dangerous and the risk of surgery has to be balanced against the
risk of not operating.
When do you operate ?
For aortic aneurysms, the main risk is of rupture, which becomes
significant when the aorta reaches 5.5cm or more. Regardless of the
size, patients with symptoms should also be considered for surgery.
In ladies, although aneurysms are less common, surgery may be
indicated slightly earlier as they generally have smaller blood
vessels to begin with.
What sort of operations are there
Traditionally, aortic aneurysms have been treated with open
repair under general anaesthetic, where the abdomen is opened and
the aneurysm is replaced with a strong fabric tube. It takes at
least a couple of months to recover your strength fully, but there
are very few later problems with this operation and for many
patients it remains the best and most suitable procedure.
With the advent of keyhole techniques, endovascular repair
(EVAR) is now a real option for up to two-thirds of patients.
Potentially this can be performed under local or epidural block
instead of a general anaesthetic, and there is less stress on the
heart and lungs during the operation. However, this involves
lifetime followup scans, and quite a lot of patients need secondary
interventions to make sure the aneurysm remains sealed off. This
can often be accomplished in the Xray department.
If I need an operation, what will
You will be seen in the clinic to discuss the options. A CT scan
of the aneurysm will be required to determine the anatomy
precisely, and this will be discussed in our meeting to decide
whether are possible. Some tests of your heart and lungs will
be arranges (CPET) to assess your overall fitness for surgery which
will be discussed with our Vascular Anaesthetist. Based on this
multi-disciplinary assessment, either an open or endovascular
repair will be recommended.
Will I get a choice ?
Yes. Your health will affect the risk of surgery, and the
anatomy of your aneurysm may favour one or other operation so your
Vascular Surgeon will have an opinion on the matter, but patient
preference is important in the decision. Some patients prefer to
have a one-off procedure with a slightly longer recovery period,
others favour the minimum risk surgery and are happy to be followed
up in case they need a second procedure. The final decision should
be one that you reach with your surgeon.
What other sorts of aneurysm are
Aneurysms of the brain arteries can occur but are looked after
by the neurosurgeons.
Aneurysms of the popliteal artery occur behind the knee. Here
the risk is more about clotting than rupture, and aneurysms over
3cm are considered for repair which may be either a bypass
operation or a stent.
A different sort of aneurysm called a pseudo-aneurysm can occur
following surgery or treatment on the arteries. This is usually at
the site of a bypass graft or where the vessel has been injured or
had a needle put in. It is due to a small hole that does not seal
and gradually gets larger. These usually require surgery if they
enlarge or cause symptoms but we won't discuss them further