What is abdominal aortic aneurysm (AAA)?
The
aorta is the largest artery in your body, and it carries oxygen-rich
blood pumped out of, or away from, your heart. Your aorta runs through
your chest, where it is called the thoracic aorta. When it reaches your
abdomen, it is called the abdominal aorta. The abdominal aorta supplies
blood to the lower part of the body. In the abdomen, just below the
navel, the aorta splits into two branches, called the iliac arteries,
which carry blood into each leg.
When a weak area of the abdominal aorta expands or bulges, it is
called an abdominal aortic aneurysm (AAA). The pressure from blood
flowing through your abdominal aorta can cause a weakened part of the
aorta to bulge, much like a balloon. A normal aorta is about 1 inch (or
about 2 centimeters) in diameter. However, an AAA can stretch the aorta
beyond its safety margin as it expands. Aneurysms are a health risk
because they can burst or rupture. A ruptured aneurysm can cause severe
internal bleeding, which can lead to shock or even death.
Less commonly, AAA can cause another serious health problem called
embolization. Clots or debris can form inside the aneurysm and travel
to blood vessels leading to other organs in your body. If one of these
blood vessels becomes blocked, it can cause severe pain or even more
serious problems, such as limb loss.
Each year, physicians diagnose approximately 200,000 people in the
United States with AAA. Of those 200,000, nearly 15,000 may have AAA
threatening enough to cause death from its rupture if not treated.
Fortunately, especially when diagnosed early before it causes
symptoms, an AAA can be treated, or even cured, with highly effective
and safe treatments.
What are the symptoms?
Although you may initially not feel any symptoms with AAA, if you
develop symptoms, you may experience one or more of the following:
- A pulsing feeling in your abdomen, similar to a heartbeat
- Severe, sudden pain in your abdomen or lower back. If this is the case, your aneurysm may be about to burst
- On rare occasions, your feet may develop pain, discoloration,
or sores on the toes or feet because of material shed from the aneurysm
If your aneurysm bursts, you may suddenly feel intense weakness,
dizziness, or pain, and you may eventually lose consciousness. This is
a life-threatening situation and you should seek medical attention
immediately.
What causes an abdominal aortic aneurysm?
Physicians and researchers are not quite sure what actually causes
an AAA to form in some people. The leading thought is that the aneurysm
may be caused by inflammation in the aorta, which may cause its wall to
weaken or break down. Some researchers believe that this inflammation
can be associated with atherosclerosis (also called hardening of the
arteries) or risk factors that contribute to atherosclerosis, such as
high blood pressure (hypertension). In atherosclerosis fatty deposits,
called plaque, build up in an artery. Over time, this buildup causes
the artery to narrow, stiffen and possibly weaken. Besides
atherosclerosis, other factors that can increase your risk of AAA
include:
- Being a man older than 60 years
- Having an immediate relative, such as a mother or brother, who has had AAA
- Having high blood pressure
- Smoking
Your risk of developing AAA increases as you age. AAA is more common in men than in women.
What tests will I need?
Abdominal aortic aneurysms that are not causing symptoms are most
often found when a physician is performing an imaging test, such as an
ultrasound or CT scan, for another condition. Sometimes your physician
may feel a large pulsing mass in your abdomen on a routine physical
examination. If your physician suspects that you may have AAA, he or
she may recommend one of the following tests to confirm the suspicion:
- Abdominal ultrasound
- Computed tomography (CT) scan
- Magnetic resonance imaging (MRI)How is an abdominal aortic aneurysm treated?
Watchful waiting

If
your AAA is small, your physician may recommend "watchful waiting,"
which means that you will be monitored every 6 months for signs of
changes in the aneurysm size. Your physician may schedule you for
regular CT scans or ultrasounds to watch the aneurysm. This method is
usually used for aneurysms that are smaller than about 2 inches
(roughly 5.0 to 5.5 centimeters) in diameter. If you also have high
blood pressure, your physician may prescribe blood pressure medication
to lower your blood pressure to lower the pressure on the weakened area
of the aneurysm. If you smoke, you should obtain help to stop smoking.
An aneurysm will not "go away" by itself. It is extremely important to
continue to follow up with your physician as directed because the
aneurysm may enlarge to a dangerous size over time and could eventually
burst if this is not detected and treated.
Open Surgical aneurysm repair
A vascular surgeon may recommend that you have a surgical
procedure called open aneurysm repair if your aneurysm is causing
symptoms, or is larger than about 2 inches (roughly 5.0 to 5.5
centimeters), or is enlarging under observation. During an open
aneurysm repair, also known as surgical aneurysm repair, your surgeon
makes an incision in your abdomen and replaces the weakened part of
your aorta with a tube-like replacement called an aortic graft. This
graft is made of a strong, durable, man-made plastic material, such as
Dacron®, in the size and shape of the healthy aorta. The strong tube
takes the place of the weakened section in your aorta and allows your
blood to pass easily through it. Following the surgery, you may stay in
the hospital for 4 to 7 days. Depending upon your circumstances, you
may also require 6 weeks to 3 months for a complete recovery. More than
90 percent of open aneurysm repairs are successful for the long term.
Endovascular stent graft
Instead of open aneurysm repair, your vascular surgeon may
consider a newer procedure called an endovascular stent graft.
Endovascular means that the treatment is performed inside your artery
using long, thin tubes called catheters that are threaded through your
blood vessels. This procedure is less invasive, meaning that your
surgeon will usually need to make only small incisions in your groin
area through which to thread the catheters. During the procedure, your
surgeon will use live x-ray pictures viewed on a video screen to guide
a fabric and metal tube, called an endovascular stent graft (or
endograft), to the site of the aneurysm. Like the graft in open
surgery, the endovascular stent graft also strengthens the aorta. Your
recovery time for endovascular stent grafting is usually shorter than
for the open surgery, and your hospital stay may be reduced to 2 to 3
days. However, this procedure requires more frequent follow-up visits
with imaging procedures, usually CT scans, after endograft placement to
be sure the graft continues to function properly. Also, the endograft
is more likely to require periodic maintenance procedures than does the
open procedure. In addition, your aneurysm may not have the shape that
is suitable for this procedure, since not all patients are candidates
for endovascular repair because of the extent of the aneurysm, or its
relationship to the renal (kidney) arteries, or other issues. While the
endovascular stent graft may be a good option for some patients who
have suitable aneurysms and who have medical conditions increasing
their risk , in some other cases, open aneurysm repair may still be the
best way to cure AAA. Your vascular surgeon will help you decide what
is the best method of treatment for your particular situation.
