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Abdominal Aortic Aneurysm

An abdominal aortic aneurysm is a dilation (ballooning) of part of the aorta that is located in the abdomen. An abdominal aortic aneurysm quite often leads to no indicators until it ruptures (bursts). A ruptured abdominal aortic aneurysm is quite often lethal. An aneurisma abdominal less than 50 mm wide carries a low probability of rupture. A surgical procedure to fix the aneurysm will be advised if it is larger sized than 50 mm, as above this size the probability of rupture raises. Men aged 65 and more are to be offered a routine scan to screen for abdominal aortic aneurysm.

What is the aorta?

The aorta is the largest artery (blood vessel) in the human body. It carries blood from the heart and descends through the chest and the abdomen. Many arteries come off the aorta to supply blood to all parts of the body. At about the level of the pelvis the aorta divides into two arteries, one going to each leg.

What is an aneurysm and an abdominal aortic aneurysm?

An aneurysm is where a segment of an artery widens (balloons out). The wall of an aneurysm is less strong than a natural artery wall. The tension of the blood in the artery leads to the weaker section of wall to balloon.

<img style="width:294px;height:270px;float:left;" src="http://www.abdominalaneurysm.net/wp-content/uploads/2012/03/AAA.gif" alt="Abdominal Aortic Aneurysm"/> <img style="width:310px;height:263px;" src="http://www.abdominalaneurysm.net/wp-content/uploads/2012/03/abdominal-aortic-aneurysm.gif" alt="Diagram showing the main arteries of the body and details of an aortic aneurysm"/>

Aneurysms could appear in any existing artery, but they most typically happen in the aorta. Most aortic aneurysms take place in the segment of the aorta that passes through the abdomen. These are recognized as abdominal aortic aneurysms (AAAs). Frequently they occur in the section moving through the chest. These are known as thoracic aortic aneurysms.

The normal dimension of the aorta in the abdomen is related to 20 mm. An abdominal aortic aneurysm is said to be present if a section of the aorta within the abdomen is 30 mm or more in diameter.

The rest of this leaflet is mainly about AAAs.

AAAs range in size. As a rule, once you develop an AAA, it has a tendency gradually to obtain greater. The rate at which it obtains larger ranges from person to person. However, on average, an AAA tends to get larger by around 10% every year.

What causes an abdominal aortic aneurysm?

In the majority of cases

The particular cause why an aneurysm forms in the aorta in most cases is not well-defined. Most situations happen in aged people. An AAA is uncommon in people less than the age of 60. Therefore, growing old has a main role to play.

The wall of the aorta ordinarily has layers of smooth muscles, and layers built from tissues named elastin and collagen. Elastin and collagen are powerful assisting tissues. What seems to happen is that a part of the aorta loses its normal toughness and elasticity in some people as they grow older. Medical studies suggests that this is because of to changes in the elastin, collagen and smooth muscle tissues. There seem to be difficult biochemical procedures that lead to these modifications. Some people are more prone than others to these changes.

Your hereditary make-up performs a part, as you have a significantly higher chance of happening an AAA if one of your parents has, or had, one.

Atheroma may also play a part. Atheroma is a oily substance that stores within the inside of lining of arteries. Atheroma is in some cases termed furring of the arteries. Most AAAs are lined with some atheroma. Any person can develop atheroma, but it develops more often with increasing age. Particular risk aspects also increase the chance of atheroma developing. They include: cigarette smoking, high blood pressure, diabetes, raised cholesterol level, taking little exercise, and obesity. These are the same risk factors that enhance the probability of atheroma forming in the heart (coronary) arteries, which can cause angina and heart attacks.

In a minority of cases

Rare triggers of AAAs have injury or infection of the aorta. Additionally, certain uncommon inherited factors can influence the artery framework. In these uncommon situations an aneurysm may develop at a quite young age.

How typical are abdominal aortic aneurysms?

About 6 in 100 men and about 2 in 100 women over the age of 65 have an AAA. It gets more regular with growing age. Though, most people with an AAA are not knowledgeable that they have one. An AAA is uncommon in people under the age of 60.

What is the concern about an abdominal aortic aneurysm?

The main concern is that the aneurysm could rupture (burst). The wall of the aneurysm is weaker than a usual artery wall and may not be able to endure the tension of blood internally. If it ruptures then severe internal bleeding occurs which is often fatal. Of course, most AAAs do not rupture - only a certain proportion (see below).

What are the signs of an abdominal aortic aneurysm?

Usually there are no signals or symptoms. At the time of diagnosis, 7 in 10 people with an AAA will not have had any symptoms due to the aneurysm. The ballooning of the aneurysm does not lead to any symptoms unless it gets large enough to put force on native structures. If symptoms do take place, they are most likely to be mild abdominal or back pains. There are many triggers of mild abdominal and back pain. Therefore, the medical diagnosis could be postponed except when the aneurysm is large enough to be felt by a medical expert when he or she examines your abdomen.

In some cases small blood clots form on the inside lining of an AAA. These may break off and be taken down the aorta and block a smaller artery further on. These blood clots are called emboli and can be dangerous. For example, total blockage of an artery that supplies a foot may lead to loss of blood to part of the foot, which can result in problems in the foot and gangrene if left without treatment.

If the aneurysm does rupture then you are likely to have sudden severe abdominal and/or back pain. This is commonly soon followed by collapse as the internal bleeding causes a sharp drop in blood pressure.

How is an abdominal aortic aneurysm diagnosed?

• Occasionally a medical professional feels the stick out of an aneurysm during a routine exam of the abdomen. Even so, many AAAs are too small to feel.
• An X-ray of the abdomen (often carried out for different purposes) will display calcium deposits lining the wall of an AAA in a few, but not all, cases.
• An ultrasound scan is the easiest way to detect an AAA. This is a painless test. It is the identical kind of check out that expecting a baby women have to look at the baby in the womb. The size of the aneurysm can also be measured by ultrasound. As discussed later, it is important to know the size.
• A more detailed scan, such as a CT scan, is sometimes done. This may be done if your medical expert needs to know whether the aneurysm is affecting any of the arteries that come off the aorta. For instance, if the aneurysm involves the section of the aorta where the arteries to the kidneys branch off, doctors need to recognize this info if they plan to operate.

What is the threat of an abdominal aortic aneurysm rupturing?

The chance of rupture is minimal if an AAA is minimal. As a rule, the risk of rupture raises with growing size. This is much like a balloon - the larger you blow it up, the greater the force, and the larger the probability it will burst open. The diameter of an AAA can be tested by an ultrasound scan. The following gives general danger figures for the size (diameter) of the aneurysm:

• 40 mm-55 mm: about a 1 in 100 chance of rupture per year.
• 55 mm-60 mm: about a 10 in 100 chance of rupture per year.
• 60 mm-69 mm: about a 15 in 100 chance of rupture per year.
• 70 mm-79 mm: about a 35 in 100 chance of rupture per year.
• 80 mm or more: about a 50 in 100 chance of rupture per year.

As a rule, for any given size, the risk of rupture is increased in smokers, females, those with high blood pressure, and those with a family background of an AAA.

Should certainly every person with an abdominal aortic aneurysm have surgery?

The short answer is no. Surgery repair of an AAA is a significant procedure and provides risks. A small quantity of people will die while in, or right after, the procedure. If you have a small AAA, the probability of loss of life caused by surgical procedures is greater than the danger of rupture. As a result, medical procedures is often not recommended if you have an AAA less than 50 mm wide. Nevertheless, common ultrasound tests will normally be suggested to observe if it gets larger over time.

Surgery treatment is normally proposed if you develop an AAA larger than 50 mm. For these larger aneurysms the probability of rupture is commonly higher than the risk of surgical treatments. However, if your basic condition of wellness is poor, or if you have certain other clinical conditions, this may raise the threat if you have surgical procedure. Therefore, in some situations the choice to operate could be a really difficult one.

Urgent surgery is necessary if an AAA ruptures. On average, about 8 in 10 people who have a ruptured aortic aneurysm will die due to the rapid critical bleeding. However, emergency surgery is lifesaving in some scenarios.

What treatments are executed?

There are two types of surgical treatment to fix an AAA.

The regular surgery is to cut out the bad part of aorta and swap it using an synthetic section of artery (a graft). This is a major operations and, as mentioned, includes some risk. Some people die throughout this operation. On the other hand, it is successful in a lot of scenarios and the aneurysm is completely fixed. The long-term outlook is fine. The graft usually works well for the rest of your life.

A modern procedure makes it possible for the aorta to be repaired by a technique called endovascular repair. This has become a popular solution in recent years. In this method a tube is passed up from inside one of the leg arteries into the section of the aneurysm. This tube is then passed throughout the widened aneurysm and fixed to the good aorta wall applying metal clips. The edge to this specific type of fix is that there is no abdominal surgical procedure. This tactic is thus safer than the traditional surgery, and you need to spend less time in medical center. A disadvantage is that some patients have to undergo an additional procedure at a later stage to refine the early surgery.

Operative tactics keep going to develop and improve. Your doctor will suggest about the pros and cons of surgical treatment, the different kinds of surgery, and the best choice for you.

Other solutions could be necessary

If you have an AAA, you are probably to have a substantial amount of atheroma that lines the artery. For that reason, you are at danger of having significant atheroma structure in other arteries, such as the coronary (heart) arteries and brain arteries. 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 some other vascular disorders, such as a heart attack or stroke.

Therefore, you should think of doing what you can to greatly reduce the threat of these factors by other means. For illustration:

• Eat a healthy diet which contains keeping a low salt intake.
• If you are able, exercise regularly.
• Lose excess weight if you are overweight.
• Do not smoke.
• If you drink alcohol, do so in moderation.
• If you have high blood pressure, diabetes, or a high cholesterol level, they should be well controlled on treatment.
• You may be prescribed a statin drug to lower your cholesterol level and low-dose aspirin to help prevent blood clots from forming.

See separate leaflet called 'Preventing Cardiovascular Diseases' for more details.

Screening for abdominal aortic aneurysm

Research studies recommend that a program ultrasound check is worthwhile for all men aged 65. This is because most people with an AAA do not have symptoms. Following a program diagnostic scan, surgical treatment can be provided to men found to have an aneurysm over 50 mm wide. Follow-up scans can be provided to monitor those with smaller aneurysms.

In early 2008, the authorities introduced that over the subsequent five years ultrasound screening would be rolled out to enable all men in England aged 65 and over to be screened. Screening is likely to begin in Scotland in 2011. Wales and Northern Ireland have yet to announce their plans. Screening for AAA is offered only to men, as the condition is much more widespread in men than in women. One study shared in 2009 predicted that if all men in their 60s and 70s were screened in England then this could save nearly 2,000 lives a year. On the other hand, there are some people who have concerns about screening for AAA; for example, see the paper by Johnson cited under 'References', below.