The aorta is the artery that carries oxygen-rich blood from the heart to the rest of the body. The part of the aorta that runs through the abdomen is called the abdominal aorta. It usually has a diameter of about 2 cm.
If one part of the aorta bulges outward and has a diameter of more than 3 cm, it is known as an abdominal aortic aneurysm (sometimes abbreviated as AAA).
People who have this type of aneurysm usually don't notice it. This is because it typically doesn't cause any symptoms. Most aneurysms aren't dangerous.
But there is a risk of the aorta suddenly rupturing (breaking open) if an aneurysm keeps on expanding. That is an emergency situation and life-threatening.
Most abdominal aortic aneurysms don't cause any symptoms and go unnoticed.
Larger aneurysms may cause back ache or abdominal pain, or pain in your sides. Then it may be discovered if a doctor looks for the source of the pain.
If the abdominal aorta ruptures, it causes sudden back pain that radiates to the sides or groin. A large amount of blood is lost through the rupture, causing dizziness, loss of consciousness and eventually circulatory collapse.
An abdominal aortic aneurysm may arise if the vessel wall becomes less elastic, for example as a normal part of aging. Other possible causes include smoking and too much pressure on the blood vessel, for instance due to high blood pressure. If one part of the vessel wall starts bulging, it tends to continue to expand, and the aneurysm grows larger.
Aorta and bulging vessel wall (aneurysm)
There are a number of factors that can increase someone's risk of developing an abdominal aortic aneurysm.
- Sex: Abdominal aortic aneurysms are more common in men than in women.
- Age: The risk increases with age. Most people who have an abdominal aortic aneurysm are over 65 years old.
- Smoking: Smoking is the most important risk factor that you can influence yourself.
- Blood pressure: High blood pressure makes an abdominal aortic aneurysm more probable.
- Blood lipids: High levels of blood lipids (blood fats) increase the likelihood of an aneurysm developing.
- Genes: People who have white skin or close relatives who have had an abdominal aortic aneurysm are at greater risk.
About 2% of all men between the ages of 65 and 75 have an abdominal aortic aneurysm. The number increases with age. Women are much less likely to have an abdominal aortic aneurysm.
Aneurysms usually continue to expand slowly. But most of them never cause any noticeable symptoms, and don't cause any problems for the rest of that person's life.
Only some aneurysms become so large that there is a greater risk of the aorta suddenly rupturing. If the aorta ruptures, a large amount of blood leaks into the abdominal cavity – a life-threatening emergency. The risk of an aneurysm rupturing is higher if the aneurysm is growing rapidly or if it is at least 5.5 cm in diameter. It is roughly estimated that aneurysms with a diameter of more than 5.5 cm will rupture within one year in about 3 to 6 out of 100 men.
Abdominal aortic aneurysms are diagnosed using ultrasound imaging of the abdomen (belly). The diameter of the abdominal aorta can be measured in this way. If the diameter of the aorta is greater than 3 cm, it is considered to be an aneurysm.
Ultrasound scans can help discover large aneurysms early on. The aneurysms can then be repaired before they rupture. If smaller bulges are found, they can be checked regularly to see whether they are growing, and how quickly.
It has been shown that screening tests for men over the age of 65 lower the risk of aneurysms rupturing and leading to death. But screening also has disadvantages: Some aneurysms are discovered and sometimes surgically repaired even though they never would have caused any problems. That is known as overdiagnosis. Also, the surgical procedure itself may cause serious complications. Knowing that you have an aneurysm can be quite distressing too.
Whether or not treatment is a good idea, and what type of treatment would be suitable, will mainly depend on the size of the aneurysm, its general development and the overall health of the person who has it. Smaller abdominal aortic aneurysms that have a diameter of less than 5.5 cm are typically checked on a regular basis. Smokers are usually asked to quit because smoking can make the aneurysm get bigger. People who have other risk factors, such as high blood pressure or high blood lipid levels, are advised to seek treatment for those conditions. But it is not yet clear whether medication can slow the growth of the aneurysm and actually lower the risk of rupture.
If the risk of rupture is high, surgery is the only preventive measure. There are two types of surgery for a large aneurysm:
- Open surgery through an abdominal incision (cut): The aneurysm is opened, and replaced by an artificial vessel (graft).
- Endovascular procedure through a small incision in the groin: A small tube (stent) is put into the artery, pushed along to where the aneurysm is, and implanted in the aneurysm.
Both of these procedures are associated with risks. Determining whether a surgical procedure is a good idea is a very personal decision: On the one hand there are risks, but on the other there is the possible danger of the aneurysm rupturing.
Open surgery on the abdominal aorta is a major procedure. So the surgery is often followed by rehabilitative therapy. The goal of rehabilitation is to minimize the negative effects of the surgery and improve quality of life. Rehabilitation offers the opportunity to slowly get back to activities of everyday life so that it's easier to return to your normal routine.
Being diagnosed with an abdominal aortic aneurysm can stir up a lot of mixed feelings. Some people are happy that their aneurysm was discovered, and the check-ups help make them feel safe.
Others would rather have not found out about the aneurysm. Knowing about it can be scary and troubling.
Many people continue with their lives with the feeling that their life is in danger. Symptoms such as abdominal pain can be frightening: They are then often thought to be associated with the aneurysm, even if that's not actually the case. Many people stop doing certain things in everyday life out of fear that the aneurysm could rupture. They become more cautious and avoid physical exertion.
Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Ultrasound screening for abdominal aortic aneurysms: Final report; commission S13-04. April 02, 2015. (IQWiG reports; Volume 294).
Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Information for health insurance fund members on ultrasound screening for abdominal aortic aneurysms – addendum to commission S13-04: commission P16-01. October 13, 2016. (IQWiG reports; Volume 449).
Paravastu SC, Jayarajasingam R, Cottam R, Palfreyman SJ, Michaels JA, Thomas SM. Endovascular repair of abdominal aortic aneurysm. Cochrane Database Syst Rev 2014; (1): CD004178.
Parkinson F, Ferguson S, Lewis P, Williams IM, Twine CP, South East Wales Vascular Network. Rupture rates of untreated large abdominal aortic aneurysms in patients unfit for elective repair. J Vasc Surg 2015; 61(6): 1606-1612.
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