A 62-year-old man presented with a 2-week history of continuous pain in the left lower abdomen radiating to the groin. For several weeks, he had complained of general malaise, including tiredness and poor appetite, and diarrhoea once or twice per day. His general practitioner palpated a pulsating, tender mass in the left groin and referred him to the department of vascular surgery at the nearby university hospital. Three years previously, he had been operated upon with a Dacron aorto-bifem- oral bypass for critical ischaemia and intermittent claudication in the left and right lower limbs, respectively. On admission, the patient was in a relatively good general condition, although his body temperature was 38.5°C, pulse rate was 96 bpm, and blood tests showed an elevated sedimentation rate, C-reactive protein (CRP) and leucocyte count. Palpation of the left iliac fossa was slightly painful. The inguinal swelling was covered by erythematous skin and was estimated to be approximately 4 cm in diameter.

Question 1

What is the most likely diagnosis at this stage?

A.  False aneurysm/pseudoaneurysm B.  Infected Dacron graft

C.  Lymphadenitis

D.  Incarcerated inguinal or femoral hernia E.  Incarcerated obturator hernia

F.  A-V fistula

Based on the clinical signs and symptoms, treatment with broad-spectrum antibiotics was started.

J.J. Jørgensen ( )

Department of Vascular Surgery, Oslo University Hospital, Aker, Oslo, Norway

Question 2

Which of the following investigations should be considered to confirm the diagnosis, and in what order?

A.  Duplex scanning B.  Arteriography

C.  Computed tomography (CT) scanning with aspiration of perigraft fluid for Gram staining and culture

D.  Magnetic resonance imaging (MRI) E.  Leucocyte-labelled scintigraphy F.  Surgical exploration

Ultrasonography revealed that the Dacron graft and femoral arteries were not pathologically dilated but that the anastomotic site was surrounded by fluid. Some of this perigraft fluid was aspirated and was found to contain coagulase-negative staphylococci (CNS). Antibiotic treatment was adjusted accordingly.

Question 3

Vascular graft infection in the groin may be primary treated without resecting the graft itself when there is:

A.  No signs of false aneurysm formation

B.  An infected anastomosis, but without bleeding C.  A thrombosed graft

D.  No septicaemia

E.  An infected anastomosis with bleeding

MRI and CT scanning revealed that only the left limb of the bifurcation graft was infected, most likely only in the groin, involving the site of the anastomosis.

Question 4

What treatment options, in addition to antibiotics, are available for the management of an infected vascular graft in the groin?

A.  Excision with or without a revascularisation procedure.

B.  Repeated extensive wound debridement, and insertion of gentamicin mats. C.  Debridement, skin closure, and insertion of a closed irrigation system. D.  Debridement and muscle flap transposition.

E.  None; use long-term antibiotic treatment only.

Sincetheproximallimitofgraftinfectioncouldnotbeascertained,itwasdecidedtooperate onthepatientwithapartialgraftresection.Becausetheindicationforprimaryoperationhad been critical ischaemia due to multilevel atherosclerotic disease, revascularisation was

planned. Therefore, a preoperative angiography was performed, which showed signs of progressive atherosclerosis as compared with previous angiograms. The proximal part of the left superficial femoral artery was occluded, whereas the distal part was patent. Of the crural arteries, only the posterior tibial was patent. The profunda femoral artery was patent but peripherallystenotic.Intherightlowerextremity,thesuperficialfemoralarterywasoccluded, but the profunda artery and three crural arteries were patent, although partially stenotic. Based on these findings, an obturator foramen bypass (OFB) on the left side was planned.

Under general anaesthesia, an 8-mm ring-reinforced polytetrafluoroethylene (PTFE) graft was implanted as an OFB between the proximal part of the limb of the previously implanted Y-graft and the distal superficial femoral artery. During the same operation, the distal part of the infected graft was resected.

Question 5

What is the most common indication for an OFB procedure?

A.  Infected femoral (false) aneurysm

B.  Revascularisation in cases with extensive local trauma

C.  Tissue scarring in the groin subsequent to radical tumour surgery, radiation or burns D.  Sciatic artery aneurysm exclusion

E.  Infection confined to the distal part of an aortofemoral bypass graft

Question 6

Describe briefly how you would perform an OFB procedure.

After a hypotensive period on the first postoperative day, the left lower limb showed clinical signs of increased ischaemia. Blood pressure at the ankle was 60 mmHg and the ankle brachial pressure index (ABPI) was 0.4 – slightly lower than preoperatively. Duplex scanning could not rule out a technical defect of the OFB, for example kinking. Therefore, an angiography via the right groin was performed, which did not show any major technical defects. Subsequently anticoagulation therapy was started.

Question 7

What is the least frequent complication of an OFB?

A.  Urinary bladder injury

B.  Injury of the obturator nerve and blood vessels

C.  Kinking of the graft due to erroneous transmuscular tunnelling

D.  Infection of the obturator graft

E.  Bleeding, thrombosis

F.  Injury of the internal iliac artery

The further postoperative course was uneventful. Two weeks later, the patient was discharged with complaints of claudication in the left lower extremity and a walking distance of approximately 50 yards. Oral antibiotics were to be continued for 3 months and anticoagulation indefinitely.

Question 8

What alternative revascularisation procedures after removal of an infected vascular graft in the groin may be considered?

A.  Subintimal angioplasty of the native iliac artery

B.  Semi-closed endarterectomy (ring-stripping) of the iliac artery C.  Axillofemoral bypass by lateral route

D.  Subvulvular bypass E.  Subscrotal bypass

F.  Bypass with autologous vein

25.1  Commentary

In patients with a vascular prosthesis anastomosed to the external iliac or common femoral artery, presenting with a painful tumor in the groin, the primary tentative diagnosis should be infected graft. Alternative diagnoses include non-infected false aneurysm, incarcerated inguinal, femoral or obturator hernia, lymphadenitis and A-V fistula. [Q1: B]

25.2 

Preoperative Measures

Even though positive cultures may be lacking, treatment with intravenous broadspectrum antibiotics, including those against anaerobic microorganisms, are initiated on clinical suspicion of graft infection alone. Late vascular graft infections may be caused by CNS, low virulent bacteria that are often difficult to diagnose by standard techniques.1

Preoperatively, it is crucial to obtain as much information as possible about the extent of graft infection. Duplex scanning ultrasonography is an appropriate first modality to evaluate perigraft or other groin masses. CT scanning is more effective in the diagnosis of aortic graft infection, especially when combined with aspiration of perigraft fluid for Gram staining and aerobic and anaerobic cultures.2 MRI can be even more reliable.3 However, optimal diagnostic accuracy may be obtained by combining CT or MRI with indium-labelled leucocyte scintigraphy.4 Duplex scanning and arteriography do not play significant roles in establishing the diagnosis of a vascular graft infection, but they are used for diagnosing