Abdominal Aortic Aneurysm, the silent disease

Abdominal Aortic Aneurysm (AAA) is one of the leading causes of death for the population over 50 years of age, causing 20,000 U.S. deaths each year. An estimated 2-3% of men over 50 or about 2 million U.S. citizens have an occult (not yet diagnosed) AAA. Most AAA patients experience no symptoms. At times an AAA patient complains about back pain or abdominal pain and a pulsation in the abdomen. This weakened section of the aorta is called an abdominal aortic aneurysm or triple A (see diagram 1: AAA). Often the primary care provider finds an AAA by chance during a routine examination of the abdomen. Since January 2007, routine screening for aneurysms has been established in the United States.

Diagram 1: AAA

What is the aorta?

The main artery that carries blood from the heart to the body is called the aorta. The aorta branches off into smaller blood vessels. The abdominal aorta has branches that supply the intestine, liver, spleen, and kidneys. The abdominal aorta divides into two leg arteries. (Bi-furcation)
 
Why do aneurysms occur?

Most aneurysms occur in men aged 65 years and older when the wall of the abdominal aorta becomes dilated where it divides into the two legs arteries. The Abdominal Aortic Aneurysm (AAA) disease is more common in tobacco smokers and people who have high blood pressure (hypertension). An aneurysm is a focal dilation of a blood vessel caused by the loss of elasticity or mechanical fatigue of the vessel wall.

What is an aneurysm rupture?

The pressure of circulating blood often causes artery to balloon out and form a bulging sac. This sac may continue to grow larger until, like a balloon, it bursts or "ruptures”. AAAs tend to get worse over time when the wall of the aorta becomes stretched and thin. A ruptured aneurysm occurs when the wall of the abdominal aorta tears, which leads to internal bleeding from the abdominal aorta into the abdomen. Even without rupture, a blood clot (thrombus) can form inside the AAA. A ruptured aortic aneurysm typically leads to the death of the patient.

How can rupture be prevented?

The risk of rupture is related to the size of the aneurysm. The size can be measured using ultrasound scans. Aneurysms of less than 5 cm in diameter will be 'watched', by doing an ultrasound scan every 6 months in order to determine the growth. If the aneurysm has grown larger than 5 cm in diameter it is necessary to repair the aneurysm surgically.

What is the gold standard in surgery to prevent ruptures?

To repair an aneurysm and prevent rupture, the diseased area of the abdominal aorta is carefully removed and replaced by an artificial graft (see diagram 2), which are permanently sewn in place.

What are the intended benefits of the surgery?

To surgically repair the aneurysm in the least traumatic way, and to prevent the aneurysm from rupture (bursting) or occlusion (blocking).

What is 'open repair' of abdominal aortic aneurysms?

Open repair of abdominal aortic aneurysms is a major operation. A hospital stay  of at least 7 to 10 days is needed. General anesthetic is administered and a large incision is made in the belly. Then the abdominal aorta above and below the aneurysm is dissected and clamped to stop the flow of blood. This enables the aneurysm to be cut open and a new artificial replacement vessel to be sewn in. After removal of the clamps the abdomen is closed and sewn up.

What is Endovascular aneurysm repair (EVAR)?

A relatively new technique that is being tested is to use a 'stented graft' or “stent-graft” to help repair AAA (see diagram 3: Dacron^® or Gore-tex^® graft supported by a metal scaffold). In a selected group of patients (depending on the anatomy of the arteries), the AAA may be repaired through small cuts in the groin under general anesthetic. The aortic aneurysm will be fixed by passing a catheter with the graft through the inside of the groin arteries (endoluminal) under x-ray control.

What are the clinical results and risks of this stent-graft technique?

Endovascular Aneurysm repair (EVAR) is a relatively new procedure and requires follow up surveillance with regular scans of the stent graft for life after surgery. The long-term results of these stent-grafts are uncertain and still being evaluated. Sometimes after this surgery further operations are needed to restore the circulation and blood supply to the legs. In challenging anatomies of arteries it is difficult or impossible to advance the stent-graft into the AAA. If blood bypasses the stent-graft (‘endoleak’) another AAA procedure may be required or the AAA may be repaired using the laparoscopic repair technique or open surgery.

What is laparoscopic repair of the abdominal aortic aneurysm?

Key hole AAA repair with the GelPort^® laparoscopic system combines the best of open surgery with minimally invasive surgery (laparoscopy). Large incisions are avoided with the use of special ports and instruments that allow repair of the AAA. The laparoscopic AAA procedure using the GelPort laparoscopic system is designed to allow for a new artificial artery sewn in through a small opening created by a 360 degree circumferential retractor (see diagram 4: GelPort system with the Alexis^® O™ Retractor).

The laparoscopic AAA technique utilizing the GelPort system mimics the repair of the ‘gold standard’ open repair in a minimally invasive procedure resulting in a safe and permanent graft fixation.