The aorta is the biggest artery in the body. It begins at the heart and runs down inside the chest into the abdomen. Along its length it gives off many artery branches that transport blood to every part of the body. It ends in the abdomen by splitting into 2 iliac arteries, which are arteries that supply blood to the pelvis and to the legs.
An aortic aneurysm is the swelling of a segment of the aorta. This occurs because the wall has been weakened. The aorta’s wall sustains pressure from the blood flowing within it. This pressure on the weakened section causes the wall to balloon out. Much like a balloon, if the wall is stretched too much, it tears. A ruptured aneurysm is usually fatal. Repair of the aneurysm is therefore preferable when it is asymptomatic.
Who is At Risk?
Patients with the following risk factors should be screened for aortic aneurysms:
About 4 in 100 men and 1 in 100 women above the age of 65 years have an aneurysm. Most people are not aware they have one.How is it Diagnosed?
As it is usually asymptomatic, most aneurysms are detected when patients are examined by their doctors for unrelated complaints. The aneurysm is detected during an abdominal examination as the doctor can feel a pulsatile mass.
Some are picked up when patients undergo Xray or CT Scan tests for other reasons.
Some patients do have symptoms such as:
Once the aneurysm is identified, a CT scan is performed to determine its anatomy.What are the risks of rupture?
The risk of rupture increases with increasing diameter of the aneurysm. As a guide, the following is the risk of rupture according to aneurysm diameter:
-40-55mm diameter: 1% chance of rupture per year
Surgery is advised for patients whose aneurysms have reached 55mm or greater in diameter.What Treatment is Necessary?
If you have an AAA, you are likely to have a significant amount of atherosclerosis. Therefore, you are likely to be at increased risk of developing heart disease (angina, heart attack, etc) and stroke.
In fact, most people who develop an aortic AAA do not die of the aneurysm but die from other vascular conditions, such as a heart attack or stroke.
Therefore, you should consider doing what you can to reduce the risk of these conditions by other means. For example:
There are two types of surgical operation to repair an aortic aneurysm.
The traditional operation is to cut out the diseased segment of aorta and replace it with an artificial artery known as a graft. This is a major operation and carries some risk. Some people die during or shortly after this operation. However it is successful in most cases and the graft usually works well for the rest of the patient’s life.
Endovascular RepairThe newer technique uses a tube called a stent placed within the aorta to that is passed up from inside the leg arteries. This tube is passed across the aneurysm and fixed to good aorta wall using metal struts. The bottom end of the tube lies below the aneurysm also along healthy aorta wall. The tube therefore acts as a channel through which blood from above the aneurysm now flows. This blood flows out of the stent into healthy arteries leading to the pelvis and legs. As there is no more blood flow into the aneurysm, the pressure on the wall of the aneurysm is greatly reduced. The aneurysm then shrinks in size.
The advantage to this type of repair is that there is no abdominal surgery. This technique is therefore safer than the traditional operation, and you need to spend less time in hospital, usually just one night. A disadvantage is that some people have to undergo a further operation at a later stage to refine the initial procedure. Also, some patient develop kinks in the stents that may lead to clot formation or to blood flowing into the aneurysm again. Fortunately these cases are rare.
In many patients, general anaesthesia and its attendant risks can be avoided.
All patients with aneurysms need to be followed up for life.