When is surgery recommended for the treatment of abdominal aortic aneurysm?
Large abdominal aortic aneurysms may rupture (break open) unexpectedly. Surgery can prevent that from happening, but carries risks of its own. So it’s important to carefully consider the pros and cons of surgery before making a decision.
The larger an aneurysm is, the greater the chances are that it will rupture. It is estimated that an abdominal aortic aneurysm that is over 5.5 cm in diameter will rupture within one year in about 3 to 6 out of 100 men. That's why surgery is often recommended. But there may also be good reasons to not have surgery.
To have surgery or not to have surgery?
Whether surgery is a good idea and when it should be done depend on two questions:
- How high is the risk that the aneurysm will suddenly rupture within the next few years?
- What are the risks of preventive surgery?
Risk of a sudden rupture
A rupture is a life-threatening medical emergency that requires immediate surgery at the hospital. About half of men who have a sudden rupture die shortly afterwards. These are the main factors that make a rupture more likely:
- The aneurysm is larger than 5.5 cm in diameter.
- The aneurysm has grown quickly (more than 0.5 cm in six months or more than 1 cm in one year).
- The aneurysm is causing symptoms such as pain in the back, stomach, or sides.
Risks of preventive surgery
Surgery on an aneurysm can lead to serious complications, especially lung complications and damage to the heart. It may even lead to death, for example due to circulatory collapse. The risk of complications is determined by various factors. One of these is the patient’s general health. For instance, people who have cardiovascular disease have a higher risk. Sometimes further surgery is needed right after surgery or at a later date.
So doctors estimate the patient’s risk of complications. Reasons not to have preventive surgery include the following:
- The person has other serious conditions, such as heart disease.
- The person's general health is so poor that a procedure seems to be too risky, for example due to old age and the associated problems.
Surgery is considered if the risk of the aneurysm unexpectedly rupturing in the next few years seems to outweigh the risks associated with the surgery.
What surgical techniques are used?
There are two techniques used to operate on an aneurysm:
- Open surgery through an abdominal incision (cut)
- Endovascular surgery through a small incision in the groin
Surgical techniques for abdominal aortic aneurysm
In Germany, about 20 out of 100 patients have open surgery and 80 out of 100 have endovascular surgery.
In open surgery, the aneurysm is removed and replaced by an artificial vessel (tube made of a synthetic material).
It is performed under general anesthesia. First, an incision is made in the abdominal wall. Then, the doctors interrupt the flow of blood in the aorta by clamping the blood vessel above and below the aneurysm. They cut the aneurysm open and implant the artificial artery (graft) there. It is sewn into place. Then the doctors wrap the vessel wall of the opened aneurysm around the graft and stitch it together tightly. After that, the normal flow of blood is restarted.
Open surgery: The aneurysm is replaced by an artificial vessel (graft)
The procedure lasts about three hours. After surgery, patients are taken to the intensive care unit and stay at the hospital for an average of 11 to 14 days. But it can take several weeks or months until you are ready to get back to your normal everyday life.
Open surgery is often not suitable for people who also have other serious medical conditions, for instance affecting the cardiovascular system, the airways or the kidneys. The procedure is too risky then. Check-ups are scheduled after surgery.
In endovascular surgery, a thin catheter is inserted into the femoral artery through a small incision in the groin. The catheter is guided through this artery to the aneurysm so that the stent graft can be implanted there. The stent graft is made of metal mesh with a synthetic coating. Once the aneurysm is reached, the stent graft is expanded using a balloon at the tip of the catheter and then attached to the aorta. The catheter is then pulled out. The blood flows through the stent. This puts less pressure on the vessel wall, lowering the risk of the aneurysm getting bigger or rupturing.
Endovascular surgery with stent graft
This procedure can be done using general, regional or local anesthesia. Patients stay at the hospital for an average of 6 to 8 days. It can take several weeks to recover fully.
After the operation, the stent graft is checked to make sure that it is in the right position, doesn't leak and is not bent. Life-long check-ups are recommended: the first is scheduled one month later, and after that they take place every 3 to 6 months, and every 12 months starting the second year after surgery. The check-ups often involve radiation because computed tomography (CT) is used to check the stent graft.
Endovascular surgery isn’t always possible. It depends on certain characteristics of the aorta and where exactly the other blood vessels branch off. A suitable stent graft has to be available too. Although endovascular surgery is less invasive than open surgery, it doesn’t offer any improved chances of survival over the long term. Compared to open surgery, it is also more likely to be followed by further surgery and more check-ups. The type of surgery you choose will also depend on what you yourself think of the advantages and disadvantages of both techniques.
Endovascular surgery for people in poor health
Endovascular surgery is mainly considered for older men if the risks of open surgery are too great – for instance, because they have a serious heart, lung or kidney disease. But endovascular surgery can itself cause unnecessary stress in this group of patients. One study involving men whose health did not allow for open surgery suggests that they do not benefit from endovascular surgery. The same number of men had died within four years, regardless of whether they had endovascular surgery or chose not to have any surgery.
What are the possible complications?
Both open surgery and endovascular surgery can lead to serious complications. Some people also die as a result of surgery. The risk of dying within 30 days of surgery is higher in people who have open surgery than it is in people who have endovascular surgery. But there is no longer any difference in this risk four years after surgery.
Surgery can also cause other complications, such as a stroke or lung problems. It may damage the heart muscle or affect the functioning of the kidneys. Sexuality may also be temporarily affected after surgery.
Compared to endovascular surgery, open surgery is typically associated with more blood loss. It also leaves behind a larger scar. Sometimes an incisional hernia develops near the surgical scar and further surgery is needed. Further surgery – usually a smaller procedure using a catheter – may also be needed for other reasons. For example, the artificial artery (graft) may become closed off following open surgery.
And after endovascular surgery, the stent graft may slip or leak. Additional surgery may also be needed if it wasn’t possible to position the stent graft properly. Or if the femoral artery was injured while the catheter was guided along it. Compared to people who have open surgery, people who have endovascular surgery are more likely to need further surgery.
Abdominal aortic aneurysms are more common in men than in women. For this reason, most studies are on the treatment of men only. So the information in the following table applies to men in overall good health. The table shows the differences between the two types of surgery, and how common the possible complications are.
|Open surgery||Endovascular surgery|
|Who are these procedures considered for?||
30 days after the surgery:
How many men died?
|About 4 out of 100||About 1 out of 100|
Four years after the surgery:
How many men died?
There was no difference four years after the surgery. In both groups, around 10 out of 100 people had died.
How many men had another surgical procedure?
|About 7 out of 100||About 16 out of 100|
More than four years after the surgery:
How many men had lung complications?
|About 8 out of 100||About 3 out of 100|
How many men had kidney complications?
|About 1 out of 100||About 1 out of 100|
How many men had a non-fatal stroke?
|About 3 out of 100||About 3 out of 100|
Deutsche Gesellschaft für Gefäßchirurgie (vaskuläre und endovaskuläre Chirurgie) (DGG). Leitlinien zum Bauchaorteaneurysma und Beckenarterienaneurysma. 2008.
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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.
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Schmitz-Rixen T, Steffen M, Grundmann RT. Versorgung des abdominellen Aortenaneurysmas (AAA) 2015. Registerbericht des DIGG der DGG. Gefäßchirurgie February 24, 2017 [E-pub ahead of print].
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