An abdominal aortic aneurysm (AAA) is a weak area in the wall of the abdominal aorta, the artery that carries blood from the heart to the rest of the body. The aorta is the body’s largest blood vessel. When an area is weak, it may bulge like a balloon when blood flows through it. The most common site for an aortic aneurysm to occur is below where the aorta divides to supply blood to the kidneys and above where it divides to supply blood to the pelvis and legs. An aneurysm that occurs in this location is called an abdominal aortic aneurysm (AAA).
Treatment of an abdominal aortic aneurysm may require surgery. For some patients, however, a new, non-surgical treatment called “stent-graft repair” can be performed by an interventional radiologist. Once an aneurysm has been diagnosed, the treatment will depend on a number of factors, such as the size of the aneurysm and the overall health of the patient. A small aneurysm may require no immediate treatment other than “watchful waiting” – checking the aneurysm regularly to be certain it does not grow. The normal diameter of the aorta is about 1 inch or less. Small aneurysms of less than 2 inches (5 centimeters) in diameter rarely rupture and may pose little risk. If an aneurysm reaches a certain size, however, there is a danger that it will burst and bleed uncontrollably (hemorrhage). In these cases treatment is necessary. If the aneurysm is small but there are symptoms, treatment may be required to prevent complications. Medication may be prescribed to lower blood pressure or to relieve pain. If the aneurysm grows to 5.5 centimeters or larger, however, physicians usually recommend treating them with surgery or with non-surgical stent-graft repair.
Stent Graft Repair
In this minimally invasive technique, an interventional radiologist uses imaging to guide a catheter and graft inside the patient’s artery. For the procedure, an incision is made in the skin at the groin through which catheter is passed into the femoral artery and directed to the aortic aneurysm. Through the catheter, the physician passes a stent graft that is compressed into a small diameter within the catheter. The stent graft is advanced to the aneurysm and then opened, creating new walls in the afflicted blood vessel.
This is a less invasive method of placing a graft within the aneurysm to redirect blood flow and stop direct pressure from being exxerted on the weak aortic wall. This relatively new eliminates the need for a large abdominal incision. It also eliminates the need to clamp the aorta during the procedure, as is done in the open surgical procedure.
Clamping the aorta creates significant stress on the hear, and people with severe heart disease may not be able to tolerate this major surgery. Stent grafts are most commonly considered for patients at increased surgical risk due to age or other medical conditions.
The stent graft procedure is not for everyone, though. It is still a new technology, and we don’t yet have data to show that this will be a durable repair for long years. Thus, people with a life expectancy of 20 or more years may be counseled against this therapy. It is also a technology that is limited by size. The stent grafts are made in certain
sizes, and the patient’s anatomy must fit the graft, since grafts are not custom-built for each patient’s anatomy.
A stent-graft is threaded into the blood vessel where the aneurysm is located. The stent graft is expanded like a spring to hold tightly against the wall of the blood vessel and cut off the blood supply to the aneurysm.