Secondary aortoduodenal fistula and the unrecognised herald bleed

Abstract

A 65-year-old man with history of aortobifemoral surgery 4 years ago was admitted to hospital after sudden abdominal pain. Initially misdiagnosed as renal colic, he was treated with analgesics, and while on observation he started with haematemesis, rapidly responding to volume infusion. Upper gastrointestinal endoscopy showed fresh blood in the stomach with no visible active bleeding. CT scan showed an important contrast extravasation from the aorta to the third duodenal portion, restarting haemodynamic instability and a cardiac arrest. Cardiopulmonary resuscitation (CPR) manoeuvres followed by intense fluid resuscitation and urgent laparotomy with a fast transabdominal supracoeliac aortic clamping was performed. After multiple blood and plasma unit transfusion and intravenous norepinephrine, two more cardiac arrests were recovered. Unfortunately, after aggressive management, the patient rapidly deteriorated and deceased on the table. Aortoduodenal fistula is a rare entity causing life-threatening bleeding. Its diagnosis requires high clinical suspicion and surgery offers the only hope for survival.

Background

Aortoduodenal fistula (ADF) is a very rare and dreaded complication after aortic graft surgery. It is usually diagnosed postmortem due to the massive upper gastrointestinal (GI) bleeding that presents after a sudden and intense abdominal pain.

Our case had a clear ‘herald bleed’ that was not identified until it was out of control, allowing a CT scan to be performed the exact moment the haemorrhage restarted. The spectacularity of the images shows a clear contrast extravasation into the duodenal frame.

After a bibliographical research, we noticed that there are images of ADF published in medical papers, but none of them showing an active bleeding that could be visualised in a three-dimensional reconstruction.

We think this case illustrates in a very graphic way the massive GI haemorrhage that occurs when this type of fistula is formed, which correlates with its high mortality rate.

This case also illustrates that any patient with a history of aortic surgery or a stent graft who develops an upper GI bleed has an aortoenteric fistula (AEF) until proven otherwise. A high suspicion index is crucial to recognise and avoid treatment delays.

An immediate CT scan should be performed, and in case of being inconclusive, a duodenoscopy should be performed ideally in the operating theatre.

Case presentation

A 65-year-old man with a history of open aortobifemoral Dacron graft surgery due to abdominal aortic aneurysm 4 years ago consulted the emergency department after a sudden intense diffuse abdominal pain 3 hours earlier with lumbar discomfort. On arrival, he was haemodynamically stable, with a diffusively tender abdomen but with no defence. Blood test showed an haemoglobin (Hb) of 13.8 g/dL and creatinine of 199 mmol/L and coagulation parameters were normal.

Initially oriented as a renal colic, he received intravenous painkillers and was taken to the observation area. Three hours later he presented hypotension and moderate haematemesis. A new Hb control had dropped to 9.5 g/dL, and fluid resuscitation and red blood transfusion were initiated. An upper GI gastroscopy was performed until the first duodenal portion due to the lack of duodenoscope after haemodynamic stabilisation, showing fresh blood in the stomach with no clots. After aspiration and saline wash, no sign of oesophageal varices, peptic ulcer or any other active bleeding source was evidenced.

The patient was hospitalised in the intensive care unit for clinical control, at which moment the case was presented to our department. Being haemodynamically stable, a CT with intravenous contrast scan was performed 20 min after our visit, during which haemodynamic instability was restarted followed by cardiac arrest. CT images showed an important contrast leakage from the aorta directly to the third duodenal portion (figures 1–3). While performing cardiopulmonary resuscitation (CPR) manoeuvres and intense fluid perfusion, the patient was rapidly transferred to the operating room despite having no vascular surgeon in our hospital and only disposing of a single aortofemoral Dacron graft on stock, in a desperate attempt to control the massive GI bleeding.

Figure 1.

Sagittal CT scan showing a contrast leakage from the aorta to the third duodenal portion.

Figure 2.

Coronal CT scan showing a contrast leakage from the aorta to the third duodenal portion.

Figure 3.

Three-dimensional CT scan reconstruction. Aortoduodenal fistula connection with active extravasation of contrast to the duodenum.

A rapid induction and intubation protocol followed by an urgent xifo-pubix laparotomy with a fast liberation of adhesions (due to aortic surgery) allowed access to the oesophagogastric junction to perform a transabdominal supracoeliac aortic clamping. A Cattel-Braasch manoeuvre permitted a complete duodenal exposure, evidencing a 1.5 cm diameter defect in the anterior aortic wall fistulising to the posterior wall of the third duodenal portion. Primary suture of the defect was performed on a nearly empty aorta. Simultaneously, CPR manoeuvres were continued with multiple red blood, fresh frozen plasma unit transfusions and autotransfusion with a Cell Saver unit and fibrinogen, high-dose norepinephrine, and bicarbonate infusion. Unfortunately and besides all efforts and aggressive management, two more cardiac arrests led to a rapidly deteriorating state, and the patient was deceased on the table.

Differential diagnosis

Mallory-Weiss syndrome, gastric/duodenal ulcer, perforation or neoplasm, oesophageal varices and abdominal aortic dissection.

Treatment

AEF treatment includes surgical aorta repair, via in situ graft placement or extra-anatomic bypass. Primary repair of the small bowel is usually performed, but may require resection and anastomosis.

Outcome and follow-up

Unfortunately, after aggressive management and all efforts, the patient rapidly deteriorated and was deceased intraoperatively during surgery.

No prodromal symptoms were registered due to the rapid development of events.

Discussion

AEF is a rare entity first described in 1829 by Sir Astley Cooper as an open link between the aorta and the GI tract.¹ Secondary AEF (SAEF) occurs in patients with previous aortic graft surgery. The main cause is thought to be by mechanical pressure of the graft against the bowel or a pseudoaneurysm due to perigraft infection or haematoma, each pulsation producing shear stress in the GI mucosa provoking erosion.² Despite its low incidence (1% approximately) historic mortality rates reached 57% depending on the surgical technique.³

In our case no symptoms were registered due to the rapid development of events. Some patients present prodromal symptoms prior to presentation such as fever, fatigue, malaise or even weight loss, describing a vague constitutional syndrome. Due to its life-threatening potential, any patient with a history of aortic surgery or a stent graft who develops an upper GI bleed has an AEF until proven otherwise.

Fistula can occur at any point of the GI tract, the third duodenal portion being the most frequent (two-thirds) due to its retroperitoneal location. Because of it, an enteroscope or a paediatric colonoscope could be used instead of a regular gastroscope so as to gain visualisation to distal duodenum and proximal jejunum.⁴ Signs such as visible graft, adherent clot, active bleeding, ulcer or pulsating mass suggest SAEF.⁵ Clinical presentation varies through patients, but the most common reported presentation is GI bleeding, which can start with a mild to moderate upper or lower bleeding; the classic triad of palpable abdominal mass, abdominal pain and GI bleeding is infrequent.⁶ Two-thirds can achieve haemostasis themselves; the so called ‘herald bleed’ temporarily seals off through a thrombus formation, lasting no more than 24 hours, which can precede lethal exsanguination.⁷ In case no surgery is performed, mortality is near 100%⁸; when surgery is performed on time, it often requires complex surgical repair associated with highly considerable morbidity and mortality.²

SAEF diagnosis is based on clinical grounds aided by readily available radiographical modalities. CT scan has an approximate 90% sensitivity and specificity; signs of gas shadow around the graft, focal wall thickening and inflammation, periaortic haematoma or soft tissue collection, or intravenous contrast within the GI lumen orientates its diagnosis.^{9 10} Clinical suspicion is key to prompt diagnosis and treatment, the treatment of choice being an immediate surgical repair.¹¹

In our case, the patient was not reconstructed. Nowadays, there are no established guidelines for repair of SAEF, and there is no gold standard technique for reconstruction, the most common being in-line reconstruction or extra-anatomic bypass. But the three major factors are most important when performing a surgical approach: bleeding control, infection prevention, and bowel and vascular reconstruction. Massive bleeding is a major cause of intraoperative and postoperative death. The surgeon’s duty is by performing damage control surgery to obtain rapid control of the haemorrhage before the lethal triad starts (hypothermia, metabolic acidosis and coagulopathy), which has been demonstrated to drastically worsen the results and increase mortality.^{12 13} In our case, the Cattel-Braasch manoeuvre (or extended Kocher manoeuvre), usually performed in patients with trauma, offered a rapid access to the retroperitoneum. It consists of an en bloc medial rotation of all the right intraperitoneal and retroperitoneal organs to the middle line. It gives an excellent exposition of the aortic bifurcation, vena cava, right ureter and kidney.^{14 15} Once the haemorrhage point has been located, direct compression on the smaller area using gauzes or fingers can gain precious time for vascular clamping.

Clinical outcomes may be affected by the different grafts used. Femoral vein and cryopreserved homografts have a lower risk of leaking when compared with fresh allografts such as femoral vein. Rifampicin-soaked endografts have been reported to have successful outcomes.¹⁶ Postimplantation syndrome may be present after SAEF treatment, characterised as persistent fever, leucocytosis with no confirmed source of infection and negative cultures.¹⁷

An open approach implies graft excision and extra-anatomic bypass or in-line reconstruction. Extra-anatomic bypass avoids placing a prosthetic graft in a contaminated field and allows simultaneous bowel repair. However, they have a reduced patency and the patient is at risk of aortic stump blow-out, infection and thrombosis. Autologous vein repair remains, for some authors, the treatment of choice in infected aortic graft surgery, using a femoropopliteal vein, which is more time-consuming, or saphenous vein spiral graft.^{18 19}

Endovascular aortic repair consists of endovascular in situ graft replacement and partial or complete graft excision. It offers a shorter duration and requires minimal anaesthesia. It also allows fistula bleeding control while planning a definitive therapy. A multicentre study comparing open vs endovascular repair showed lower overall morbidity in endovascular patients (25% vs 77%), but secondary infection relapse persisted due to the incomplete removal of the infected graft.²⁰

Current advances in interventional radiology enable a two-staged approach, delaying definitive surgery until after bleeding control through a stent graft.^{21 22} When available, aortic occluders such as intra-aortic balloon occlusion or resuscitative endovascular balloon occlusion of the aorta are a recognised feasible strategy for fast temporary control of intra-abdominal bleeding or shock in patients with trauma. It is relatively easy to place and allows aortic bleeding control faster and easier than other techniques; its complications are organ ischaemia and reperfusion damage, recommending an intermittent deflection of the balloon and direct hand compression to allow limb blood flow.²³ Once haemodynamic stability is achieved, vascular repair through abdominal or extra-anatomical bypass can be attempted by an experienced vascular surgeon. Vascular reconstruction is usually decided according to vascular surgeons’ preferences. Usually the chosen technique is an extra-anatomic bypass (axillobifemoral bypass) followed by infected graft extraction and creation of an aortic stump. In situ reconstruction is more frequently performed in cases with negligible infrarenal aortic neck or young healthy patients.³

Bowel reconstruction strategies also play an important role on mortality. Endovascular management without later bowel reconstruction, isolation of the affected duodenal area and antibiotic therapy are associated with a high incidence of persistent or recurrent infection.¹⁸ Duodenal reconstructive techniques include primary repair, resection with primary anastomosis and exclusion. A retrospective review by Howard et al²⁴ compared different approaches; duodenal leaks remained the major complication, delaying recovery and increasing morbidity and mortality. Duodenal exclusion with gastrojejunostomy had the lowest rate of duodenal leaking.

Broad-spectrum antibiotics should be administered early, covering Gram-positive, Gram-negative and anaerobes, after the excision of the infected graft. Piperacillin/tazobactam, vancomycin and gentamicin provide an empirical coverage for the majority of the germs usually identified. Antibiotic therapy should be continued intravenously at least for 4–6 weeks, followed by long-term oral antibiotics.^{25 26} Failure to treat sepsis may result in 60% mortality.

AEF is a rare and dreaded complication of aortic graft replacement in which clinical presentation may vary, making its diagnosis difficult. A multidisciplinary team approach is usually requested, including vascular surgeon, general surgeon and interventional radiology. Any patient with a history of aortic graft repair presenting with upper GI bleed has an ADF until proven otherwise. High index suspicion and clinical judgement is crucial to establish prompt diagnosis that directly affects prognosis, which will depend on the haemodynamic status on presentation, surgical time and technique, and postoperative complications.

Learning points.

• Any patient with a history of aortic graft repair presenting with upper gastrointestinal bleed has an aortoduodenal fistula until proven otherwise.

• Secondary aortoenteric fistula remains a highly lethal condition with mortality rates over 50%.

• Recognise the ‘herald bleed’ as an alarm sign.

• High index suspicion is crucial for an early diagnosis.

• Endovascular approach can be used as a temporary or definitive method to stop bleeding.