ABC of Vascular Disease

Aneurysmal Arterial Disease

1. What is aneurysmal arterial disease?
Aneurysmal arterial disease is a slow process through which arteries throughout the body become progressively enlarged.  Arterial aneurysms are uncommon and do not normally cause symptoms until a complication occurs.

2. What causes aneurysmal arterial disease?
The arteries are not simply rubbery tubes that carry blood from the heart; they are complex, living structures.  The blood is pumped into the arteries at pressure by the heart and the wall of the artery must be strong enough to withstand this pressure and the artery must be durable to withstand the repeated pulses for many years.  The wall of an artery is a living structure that is constantly being damaged and repaired.  Even a small deficiency in this process can, over many years, lead to a progressive change in the composition of the artery wall.  In aneurysm disease this repair process is not complete and the wall of the artery loses its resilience and becomes less durable.  The outcome is that the wall of the artery stretches very slowly, driven by the pressure of the blood inside, to form an aneurysm.  At the same time as the artery increases in diameter it also increases in length and this may cause the artery to become bent and tortuous.  The flow of blood in an aneurysm is disturbed by the change in shape and causes clot to be deposited in the regions where the blood is flowing very slowly.  This clot has no strength and does not protect the wall of the artery from the pressure of the blood.  As the artery gets larger the stress on the wall increases and the rate at which the wall stretches also increases. 

3. Does everyone get aneurysmal arterial disease?
No, it only seems to affect a proportion of people but there are some risk factors which are associated with the development of arterial aneurysms:

4. What are the symptoms of arterial aneurysmal disease?
Usually there are no symptoms at all until the condition is well advanced or a complication occurs.  The progressive stretching of the artery is very slow, occurring over years, and is not painful.  At the end stage of the condition the artery may enlarge rapidly and this is sometimes painful.

5. What are the complications of arterial aneurysmal disease?
There are two serious complications of arterial aneurysms: rupture and occlusion.

An aneurysm will rupture if it reaches such a size that the wall can no longer withstand the stress generated by the blood pressure.  If an aneurysm ruptures the blood leaks out into the surrounding tissues causing a haematoma.  The artery that most commonly develops this complication is the artery in the abdomen (aorta).  Rupture of an aortic aneurysm is an emergency and there is a very high risk of loss of life.

An aneurysm will occlude if the blood clot within it causes the blood to flow in a tortuous path through it.  A change in the shape of the blood clot can then block the artery completely.  The artery that most commonly develops this complication is the artery just behind the knee (popliteal artery).  Occlusion of a popliteal aneurysm is an emergency and there is a high risk of leg amputation. 

6. What can I do to prevent aneurysmal arterial disease from getting worse?
There is no evidence that restricting your lifestyle makes any difference.  It is important to seek medical advice regarding testing for the other treatable risk factors, such as high blood pressure, and getting treatment if they are confirmed.  There are no drugs that can prevent or stop the development of arterial aneurysms.

© S.R.Dodds 2001