1. What is an aneurysm?
An aneurysm is defined as an enlargement of a specific artery. They can occur in various locations, but we are dealing with the aorta, as the most common site. Our website deals mainly with abdominal aortic aneusysms, which means localized to the abdominal (belly) aorta. An aneurysm is actually defined as measuring at least 1.5 times the normal diameter of the artery. Many studies are underway in order to determine why arteries become aneurysmal. The major concern about aneurysms is their risk for rupture. As the aorta enlarges in diameter, the tension on the wall increases. The larger the aneurysm, the higher the rate of rupture. Rupture means that the aneurysmal wall cracks or breaks, and then a large amount of blood starts to leak or flow out of the aneurysm. This event is associated with a low chance of survival (25 - 50%). Treatment of abdominal aortic aneurysms is performed in order to prevent the sudden rupture and thus improve longevity.
2. Do aneurysms cause any symptoms?
Most aneurysms produce no symptoms. Therefore, many patients are not aware they have an aneurysm. Some patients may feel back pressure as the aneurysm pushes against the bony spine. This can occur as the aneurysm grows to a large size or expands rapidly. However, the majority of people with abdominal aortic aneurysms have no specific symptoms. In many cases, the aneurysm may be seen on X-ray studies such as CT scans or ultrasound. Roughly 70% of aneurysms can be detected on physical exam of the abdomen.
3. What is the stent graft endovascular treatment of AAA's?
Instead of the direct resection of the aneurysm, a stent graft is placed inside the aneurysm. The device is supported by a wire framework, in order to avoid collapse. The stent grafts usually come in different sizes, so that a tight fit can be achieved at the proximal and distal ends of the aneurysm. This device is introduced through a small incision in both groins. The entire procedure is performed either in the operating room or radiologic suite. A successful outcome means that the arterial pressure is eliminated from the aneurismal wall by the stent graft. Thousands of patients have now been treated by this procedure in the US and around the world. The FDA has recently approved two different stent grafts for treating AAA's and more will be released in the future.
4. How do I know if I am a candidate for the stent graft treatment of AAA's?
Basically, the workup for patients with AAA's being considered for the stent graft involves two tests: Helical CT scan of abdomen/pelvis and Angiogram of aorta and runoff with special catheter to measure lengths. These two tests provide the various diameters and lengths needed to size the AAA properly. Iliac arteries that are small, heavily calcified or extremely tortuous may not allow passage of the stent graft into the aneurysm via the femoral arteries in the groin. In some cases, the aneurysm begins just below the renal arteries, which means there is no neck. Most stent graft devices require at least a 10 mm neck length, and one device > 5 mm length. Although stent grafts can be inserted inside AAA's with either no neck or severe angulation, the chance of a good permanent seal is not good.
5. What are the clinical results using stent grafts for treating AAA's?
Based on the worldwide experience, the results of endovascular stent graft AAA repair in both high and low risk patients are quite impressive. Overall success ranges from 91-98% Mortality 2% Conversion rate 4% (convert stent graft technique to open repair) Endoleak 2 -15% (incomplete seal by stent graft or feeding lumbar artery or ima) Graft limb thrombosis <2% Bloodloss minimal
6. What is the usual length of hospital stay, recovery time, and followup?
The stent graft AAA technique requires around 2 hours. Anesthesia is usually provided by epidural technique. Most patients are able to go home by the next day or two. Full resumption of activity is allowed after 7-10 days. Followup is carried out 1 week postop, then at 1, 6,12 months with CT scans. Yearly followup is then recommended. This type of continual surveillance is necessary, in order to be able to detect endoleaks or other problems, should they arise. Some patients cannot tolerate CT scans due to renal impairment, so other diagnostic studies are performed.
