Volume 32, Issue 2 , Pages 146-148, August 2006
Pancreatic Abscess Involving the Aortic Graft Following Repair of a Ruptured Aortic Aneurysm: Successful Replacement with Femoro-popliteal Vein
Article Outline
Abstract
Acute pancreatitis is a rare complication after aortic surgery and carries a high mortality. We report the successful management of an infected aortic graft secondary to complicated severe pancreatitis in a 77-year-old man by open drainage of the abscess and replacement of the prosthetic graft with superficial femoro-popliteal vein (SFPV). The patient remains free from infection with a patent graft 8 months later.
Keywords: Aortic aneurysm, Graft infection, Pancreatitis
1. Introduction
Acute pancreatitis may complicate approximately 1% abdominal aortic aneurysm (AAA) repairs but a pancreatic abscess involving the aortic graft is exceptionally rare and represents a considerable challenge to the vascular surgeon.1 We report the occurrence of a pancreatic abscess involving an aortic graft following repair of a ruptured aortic aneurysm and its successful replacement with femoro-popliteal vein.
2. Case Report
A 77-year-old male underwent emergency repair of a leaking infrarenal abdominal aortic aneurysm with a Dacron tube graft. Preoperatively he suffered 40
min of moderate hypotension (<100mmHg systolic) with two short episodes with a systolic pressure of about 50mmHg but remained normotensive once the aortic clamp had been applied. No preoperative imaging of the aorta was undertaken. At operation he was found to have an aortic aneurysm arising well below the renal arteries with a substantial haematoma and free intraperitoneal blood. No other intra-abdominal abnormality was noted during exploration. He underwent a transfusion of 10 units of blood and 1.5l of salvaged blood preoperatively. He made a slow but uneventful postoperative recovery apart from a transient episode of abdominal pain at 2 weeks after the aneurysm repair with a raised white cell count (WCC), which settled spontaneously. The serum amylase was not measured and no abdominal ultrasound was performed at the time. His abdominal wound healed without infection. He was discharged to convalescence 4 weeks later.
He was readmitted 6 weeks postoperatively with abdominal pain, nausea and lethargy. Abdominal examination revealed tenderness and fullness in the left upper quadrant and flank. He was anaemic with a haemoglobin of 6.9g/dl. The WCC was 17.4×109 and C-reactive protein (CRP) was 342. His serum amylase was normal. A CT scan of his abdomen showed a lesser sac fluid collection and multiple intra- and retro-peritoneal fluid collections communicating with the aneurysm sac, containing gas that was highly suggestive of graft infection (Fig. 1). The proximity of these collections to the pancreas raised the possibility of acute pancreatitis after the initial aneurysm repair. The pancreas itself showed only mild oedema on CT.
Fig. 1.
CT abdomen showing fluid collection with gas in the left upper quadrant and around the graft.
Ultrasound guided aspiration revealed frank pus, which grew methicillin resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae, Morganella morganii and Enterococcus faecalis and had an amylase content of 38,230U/l. Percutaneous drainage was incomplete because some of the fluid collections were inaccessible and multiloculated. He, therefore, underwent laparotomy to drain the abscesses. At laparotomy there was free pus in the peritoneal cavity and the retroperitoneum. There was fat necrosis and omental calcification consistent with pancreatitis but the pancreas itself was obscured by adhesions. There were no gallstones. He was managed with appropriate broad-spectrum antibiotics (initially teicoplenin, imipenem and metronidazole with a later substitution of linezolid for teicoplenin and continued for 7 weeks), weekly abdominal CT scan and peritoneal washouts every 3 days. Three weeks later his general condition had improved sufficiently to allow definitive surgery. He underwent laparotomy, cysto-gastrostomy to drain the lesser sac abscess, drainage of all other remaining abscesses including a pelvic and a left paracolic abscess. The Dacron tube graft, which was bathed in pus, was completely excised and replaced with a reversed SFPV aortoiliac graft as previously described.2, 3 An extension SFPV graft from the right iliac anastomosis to the right femoral artery was added because the external iliac artery occluded during the operation. His abdomen was left open and a polypropylene mesh was sutured over the defect. He was returned to the operating theatre twice to narrow the mesh, which was excised when the abdomen was closed 2 weeks later. He left hospital after 8 weeks and remains well 8 months later with no intra-abdominal collections and a patent graft on CT (Fig. 2) and duplex scanning. Postoperative lower limb swelling was mild and equal in both the donor and contralateral leg.
Fig. 2.
Follow up CT showing the two limbs of the graft with no residual abscess.
3. Discussion
Acute pancreatitis is a rare complication of AAA surgery with a high mortality.4 The true aetiology is unknown but ischaemic injury due to hypotension, atheroembolism or direct trauma has been implicated.4 Of these possible causes only hypotension was present in our patient but its degree was not unusual for a patient with a ruptured aortic aneurysm and was not associated with any postoperative renal impairment. Subsequent pancreatic necrosis or infected pseudocyst poses a severe risk of graft infection. The correct diagnosis of pancreatitis is easily missed because symptoms and signs may be masked by wound pain, the serum amylase may be normal and prolonged ileus or leucocytosis is common during ventilation in the intensive care unit. In many cases the diagnosis is only made at laparotomy or autopsy.4 We presume that our patient suffered pancreatitis following the ruptured aortic aneurysm and its repair leading to the formation of a pancreatic abscess that subsequently became infected by blood born organisms from intravenous lines or the gut.
The standard operation for infected aortic grafts has until recently been graft excision, oversewing of the stump and creation of an extra-anatomical bypass but this is associated with a considerable risk of graft occlusion, re-infection and aortic stump blow-out.5 In situ replacement with antibiotic-bonded or silver-impregnated prosthetic grafts has also been advocated, but these frequently become reinfected. Cryopreserved allografts are a viable alternative but are prone to aneurysmal degeneration and are not readily available in the United Kingdom. Like others,6, 7 we have previously obtained excellent results with SFPV for the replacement of infected prosthetic grafts and mycotic aneurysms.2, 3 It provides a reasonable size match for the infra-renal aorta, is resistant to infection, rarely becomes aneurysmal and has excellent long-term patency without significant venous morbidity.6, 7 For these reasons we now consider in situ SFPV graft replacement to be the best option for the replacement of infected prosthetic aortic grafts and was chosen in this patient. SFPV has also been used successfully to repair a saccular aortic aneurysm in the presence of a pancreatic abscess.8 SFPV reconstruction with appropriate broad-spectrum antibiotics was successful here despite gross contamination with pus containing pancreatic enzymes and several pathogens, including MRSA. Prophylactic laparostomy was also used here to prevent abdominal compartment syndrome9 and to provide easy access to any recurrent abscesses.
References
- Gastrointestinal complications following infrarenal endovascular aneurysm repair. Vasc Endovasc Surg. 2004;38:137–142
- . Use of superficial femoropopliteal vein for suprainguinal arterial reconstruction in the presence of infection. Br J Surg. 2000;87:771–776
- . Experience with femoro-popliteal vein as a conduit for vascular reconstruction in infected fields. Eur J Vasc Endovasc Surg. 2003;25:424–431
- . Acute pancreatitis following aortic surgery. Am Surg. 1999;65:423–426
- . Infection in prosthetic vascular grafts. In: Rutherford RB editors. Vascular surgery. 6th ed. Philadelphia, PA: WB Saunders; 2005;p. 875–892
- . Aortic graft infections: replacement with autogenous vein. Cardiovasc Surg. 2001;9:419–425
- . Ten-year experience in aotogenous reconstruction with the femoral vein in the treatment of aortofemoral prosthetic infection. Eur J Vasc Endovasc Surg. 2003;25:240–245
- . Repair of a saccular aortic aneurysm with superficial femoral-popliteal vein in the presence of a pancreatic abscess. J Vasc Surg. 2000;32:1215–1218
- . Abdominal compartment syndrome. Crit Care. 2000;4:23–29
PII: S1078-5884(06)00051-7
doi:10.1016/j.ejvs.2006.01.005
© 2006 Elsevier Ltd. All rights reserved.
Volume 32, Issue 2 , Pages 146-148, August 2006
