A 56-year-old female from Greece with a history of

Figure: CT scan of the abdomen showing a large anastomotic aortic aneurysm.

Her past medical and surgical history was rich: rheumatic fever (1959), premature labour and eclampsia (1970), extrauterine pregnancy (1972), caesarean section (1982), small intestine ileus due to adhesions (1982), bilateral aortocarotid bypass and aortofemoral bypass (1992), which were both attributed to Takayasu's arteritis . Also, erythema nodosum (1992), appendectomy (1992), jaundice due to hepatitis B virus infection (seronegative at time of presentation), operations for femoral artery aneurysms (1994, 1995, 1997, 2001), cholecystectomy (1995), and coronary main stem bypass using the internal mammary artery (1999).

Physical examination on admission showed temperature 37.5 degrees Celsius. There were scars from previous operations. A bruit was audible over the left carotid and her femoral arteries. Right radial artery was not palpable. Laboratory testing on admission showed erythrocyte sedimentation rate (ESR) 60 mm/ 1st hour (normal<10) and C-reactive protein (CRP) 3mg/dl (normal<0.5). An electrocardiogram showed T wave inversion in leads V1 and V2. A magnetic resonance imaging (MRI) of the area of the aortofemoral graft was suggestive of active inflammation of the graft and of the surrounding area as well as adhesions of the third (retroperitoneal) part of the duodenum with the abdominal aorta.

She was treated with iv trimethoprim/sulphomethoxazole (80/400 mg) every 12h, iv chloramphenicol 1gr every 6h, iv quinupristin/dalfopristin 500 mg every 8h, sc enoxaparin 60 mg every day, ranitidine 150 mg every 12h, acetylsalicylic acid 100 mg once daily, atorvastatin 20 mg once daily, isosorbide mononitrate 60 mg once daily, and metoprolol 50 mg every 12h. Laboratory indices of inflammation initially improved and fever stopped. However, her aortofemoral graft infection seemed to be resistant to medical treatment.

What is the appropriate management?

Management
The patient was transferred to a French hospital for evaluation, for a possible surgical management of the infected aortic graft with an arterial allograft. The operation was performed in late December 2002 with success. The infected part of the aorta, including the graft was removed, wide surgical debridement was performed and a cryopreserved allograft was transplanted. The operative findings included infiltration of the wall of the duodenum by the infectious process. She did not receive any immunosuppressive therapy for the allograft. For the next three months the patient remained symptom-free but afterwards she was admitted to the hospital for investigation of abdominal pain, diarrhea and vomiting of two-day duration. After several diagnostic exams she was discharged with the diagnosis of cured gastroenteritis with suggestion for bimonthly follow up, due to her past medical history. The patient was non-compliant to the medical suggestions and presented to us six months later with left lower abdominal quadrant pain. Palpation of the area revealed a big, tender, pulsating mass. An emergent CT scan was performed (Figure). The patient died out of ruptured aortic aneurysm a few minutes after the CT scan was performed. The clips from the last operation, as seen on CT scan, indicated that the aneurysm originated at the anastomosis of the allograft.

Teaching Points

• In the case presented here, treatment of the aortofemoral graft infection was unachievable by medical management alone. Although appropriate antibiotics were administered, taking into account the possible infectious agents in the graft area, surgical debridement and graft removal became necessary. Graft excision and axillofemoral bypass, in situ prosthetic replacement with or without autogenous tissue coverage, and allograft transplantation, were the main choices for further management of the patient. The axillofemoral bypass was considered inappropriate method for a patient with extensive arterial disease such as Takayasu. Based on the medical history and the general condition of the patient, and taking into account studies about reinfection rates and other complications for each of the above methods, allograft transplantation was considered to be the most promising method.
• Although the extensive operation with the use of an aortic allograft controlled the infection, formation of an anastomotic aneurysm occurred in our case, and rupture of it, nine months post-operatively, was the cause of the patient's death. Anastomotic aneurysm formation is a relatively common complication after vascular operations in patients with Takayasu's. According to Miyata et al the cumulative incidence at 20 years post-operatively, for this complication, reaches 13,8%. Whether the incidence will change for operations with use of allograft remains to be further studied. The aneurysm formation could also be a natural evolution in arterial homografts or even be result of persisting infection in the area.
• Our case illustrates the limitations in the management of aortic graft infections in patients with Takayasu's disease, due to the difficulty of using the option of an extra-anatomical vascular bypass such as an axillary-femoral bypass. In addition, even newer surgical options regarding the management of aortic graft infections, such as the use of an aortic allograft, may be associated with high complication rates, including formation of anastomotic aneurysm(s), in patients with Takayasu's disease.

Reference List

1. Young RM, Cherry KJ, Jr., Davis PM, Gloviczki P, Bower TC, Panneton JM et al. The results of in situ prosthetic replacement for infected aortic grafts. Am.J.Surg. 1999;178(2):136-40.
2. Koskas F, Plissonnier D, Bahnini A, Ruotolo C, Kieffer E. In situ arterial allografting for aortoiliac graft infection: a 6-year experience. Cardiovasc.Surg. 1996;4(4):495-9.
3. Kieffer E, Gomes D, Chiche L, Fleron MH, Koskas F, Bahnini A. Allograft replacement for infrarenal aortic graft infection: early and late results in 179 patients. J.Vasc.Surg. 2004;39(5):1009-17.

Acknowledgment

1. This case was prepared for our website by Ioannis A. Bliziotis, M.D.
2. A modified version of this case accompanied by a literature review was submitted for publication.