Clinical Presentation

Inflammatory AAAs differ from other AAAs (Figure 1). Female patients generally account for less than 5% of patients with inflammatory aneurysms, whereas they ordinarily account for approximately one third of patients with routine AAA. Most patients with inflammatory aneurysms have symptoms of either back or flank pain. Inflammatory aneurysms tend to be more easily palpable at the time of diagnosis because of their large size. In addition, many of these patients have tenderness on palpation of the aneurysm. Patients with inflammatory AAAs tend to be younger (mean age, 62.2 years), whereas those with noninflammatory aneurysms are older (mean age, 68.2 years). Erythrocyte sedimentation rates (ESR) are elevated in approximately 75% of patients with inflammatory aneurysms. If one could define the classic patient with an inflammatory abdominal aortic aneurysm, the patient would be male, in his early 60s, with a large abdominal aneurysm, pain on palpation, weight loss, and an elevated ESR. Aside from the elevated ESR, this presentation can mimic an acute rupture of an abdominal aortic aneurysm or even an acute dissection.

Operative Management

The most striking feature of inflammatory AAAs is the focus of the inflammatory process. The anterior and lateral borders of the abdominal aneurysm may be covered by dull pink or glistening white connective tissue. The duodenum is almost always adherent to the aneurysm wall. In addition, the colon, the mesentery of the small bowel, and the jejunum often are adherent and involved in this large inflammatory process. In some patients, the inflammatory process extends cephalad and can involve the suprarenal aorta, but most of the time the inflammatory process is confined to the infrarenal aorta. Most of the inflammatory process involves the anterior and/or lateral walls of the aorta. The posterior wall is often spared. Therefore, rupture of this aneurysm can occur, and if it occurs, it generally ruptures posterolaterally into either the flank or along the area around the vertebral column.

Surgical treatment for inflammatory aneurysms consists of a graft insertion performed from within the aneurysm sac. The periaortic inflammatory reaction is highly vascular, and multiple vessels transverse it. The tenacity with which the organs and loops of bowel are fixed to the aneurysmal mass makes mobilization of these structures quite difficult and dangerous, and mobilization should not be attempted owing to the risk of bleeding or serosal injury to the bowel wall.

Many authors suggest using the extraperitoneal approach to facilitate aneurysm repair. We feel that surgeons should use the method with which they are most familiar. There is little benefit to an extraperitoneal approach over a midline approach if the aneurysm repair is performed within the aneurysm sac. Surgeons who routinely take an extraperitoneal approach will likely find that approach feasible for inflammatory aneurysms.

Proximal control of the aorta can usually be obtained below the level of the renal arteries. If it cannot be obtained there, then supraceliac control may be required. Another alternative for proximal control of the aorta is the use of an intraaortic occlusion balloon. Distal control of the aneurysm can usually be obtained in the common iliac arteries. If the common iliac arteries are involved in the inflammatory process and obtaining control is difficult, then the external iliac arteries are usually uninvolved. Hypogastric control can be obtained with balloon catheters after the aneurysm sac is opened.

Once proximal and distal control is obtained, the aneurysm is opened in an area that does not risk injury to the adherent structures. Care is taken not to open the aneurysm close to the adherent duodenum or small bowel. Because of the vascularity of the inflammatory mass surrounding the aneurysm, we use electrocautery to open the aneurysm. Once the aneurysm is opened, the mural thrombus is removed and the lumbar arteries are ligated from within.

An appropriate-sized graft is then sutured in place to an uninvolved proximal segment of aorta with standard continuous monofilament suture. We often use a larger-than-standard needle for this repair. Felt pledgets are often used to support the posterior wall of the repair. After the proximal anastomosis is complete and checked, the proximal clamp can be removed and placed on the body of the graft. If a suprarenal or supraceliac aortic cross clamp was used, it can be moved down expeditiously following the proximal anastomosis to restore flow to the foregut and kidneys. The distal anastomosis is usually performed in a standard fashion.

When the surgeon is confident that hemostasis has been obtained, the native aortic sac is closed over the graft. Often this cannot be done because of the thickness and rigidity of the inflammatory mass. We suggest covering the graft with retroperitoneal tissue if possible. If not, the use of an expanded polytetrafluoroethylene (ePTFE) membrane should be considered.

When undertaking an open repair of an inflammatory AAA, it is prudent to place ureteral stents. They allow identification of the ureters during the operative procedure and lessen the risk of injury to them. In addition, they might also improve renal function by reducing obstruction of the ureters. Operative treatment of the ureteral obstruction depends upon the degree of obstruction and kidney function. If the patient has severe hydronephrosis, it may be prudent to place ureteral stents or even percutaneous nephrostomy tubes several days before operation to allow time for renal function to improve. For severe obstruction, ureterolysis is recommended. It must be kept in mind, however, that many authors have reported a decrease in the fibrosis involving ureters following replacement of the aortic aneurysm with a graft. Most patients who have minimal compression of their ureters as a result of fibrosis have resolution of ureteral obstruction following the repair of the aneurysm.

In the original report by Walker and associates, six of the 19 patients operated upon with inflammatory aneurysms did not survive the procedure. Now only a 3% to 4% operative mortality is reported. By avoiding extensive dissection and following the methods described, we believe that acceptably low morbidity and mortality can be achieved.