Most aneurysms occur in the aorta, which is the main artery that carries blood from the heart to other parts of the body. These aneurysms are categorized depending upon their location in the aorta. An abdominal aortic aneurysm (AAA) occurs in the section of the aorta where it divides to supply blood to the kidneys, pelvis, and legs.
Who is at Risk for AAAs?
White men ages 60 to 80 are most at risk for developing AAA. While it is not yet known what causes AAAs to develop, there are certain risk factors that have been identified:
How Are AAAs Diagnosed?
Typically, AAAs do not display symptoms. Whenever an aneurysm causes symptoms, such as the new onset of back pain or abdominal pain, it is an emergency that requires urgent evaluation. If the symptoms are determined to be caused by the aneurysm, that is an indication for immediate treatment.
Most AAAs are diagnosed during a routine physical examination or imaging procedure such as ultrasound, echocardiogram, X-ray, MRI, or CT scans for another condition. Some patients may experience a pulsating sensation in their abdomen, and aneurysms can cause pain in the back or legs, although this is relatively uncommon. There is a role for screening certain patient populations for abdominal aortic aneurysms by ultrasound. The reason for diagnosing these aneurysms early is the difference in the mortality rate with a ruptured aneurysm versus elective treatment of the aneurysm. The mortality rate from ruptured aneurysms ranges from 50% to 90%, whereas the mortality rate for elective aneurysm repair performed by an experienced surgeon is 2% to 4%.
If an aneurysm is detected, further imaging procedures will be done to find out its size, shape, and exact location. These procedures are usually repeated on a regular schedule to see how fast the aneurysm is growing.
Why Are Abdominal Aortic Aneurysms So Dangerous?
The greatest danger of an abdominal aortic aneurysm is that it could rupture, which is almost always fatal. Few patients who experience a rupture survive long enough to reach the hospital. However, when diagnosed early, most AAAs can be successfully treated.
What Treatments Are Available?
AAAs less than 5 centimeters in size rarely rupture, so they are frequently treated with antihypertensive drugs or beta blockers. The risk of rupture in AAAs larger than 5 centimeters increases with increasing size, and therefore surgery is usually recommended. There are two ways to perform the surgery: traditional abdominal surgery and endovascular surgery.
Traditional abdominal surgery: In this method, which has been used successfully for more than 50 years, an incision is made from the breastbone to just below the navel while the patient is under general anesthesia. A graft made of Dacron or Teflon is sewn into place on the aorta, and the walls of the aneurysm itself are wrapped around and stitched onto the graft. The procedure takes three to six hours, and usually requires a hospital stay of five to seven days. The full recovery process is typically around six weeks.
An alternative approach favored by some surgeons is called the retroperitoneal approach. In this case, the incision is through the flank and “behind the intestines." The advantages of this type of surgery are that both the post-operative hospital stay and overall recovery times are shorter, and the surgical scar is less obvious.
Endovascular surgery: This state-of-the-art method of treating AAAs is less invasive. This operation can be done under general or epidural anesthesia, and the graft is put in place via catheters inserted through small incisions in the groin. The endovascular surgeons use X-rays during the surgery to place the graft in the proper position.
This method takes two to five hours, and many patients can go home from the hospital within two days of surgery. Full recovery time is usually one to two weeks. The procedure is very safe. Although the long-term durability of the grafts is still somewhat lower than those placed in the traditional surgery method, it is an ideal procedure for certain patients. Patients who undergo endovascular surgery for AAA will need to have regular exams on a long-term basis to track the status of their aneurysm.