Post-traumatic pseudoaneurysm of the common hepatic artery with duodenal fistula

Abstract

Background

Post-traumatic pseudoaneurysm of the hepatic artery is rare, especially after blunt abdominal trauma; an even more rare occurrence is enteric fistulisation.

Case outline

A 29-year-old man was admitted with an acute episode of upper gastrointestinal bleeding three months after blunt abdominal trauma and was found to have an hepatic artery pseudoaneurysm with duodenal fistula. Surgical treatment was by ligature of the artery and duodenal closure with omental patch.

Discussion

There is one previous case report of hepatic artery pseudoaneurysm as a delayed complication of blunt abdominal trauma. The presence of a haematoma in the hepatoduodenal ligament after blunt trauma should raise the suspicion of hepatic artery injury, and surgical exploration may prevent the subsequent development of pseudoaneurysm. CT scan has become an important instrument both in diagnosis and in surgical planning.

Introduction

Aneurysms are the most common surgical problem of the hepatic artery. Initially described by Wilson in 1819, the most frequent location is the common hepatic artery ¹. Atherosclerosis and other congenital and degenerative processes are the commonest causes. Wider application of vascular surgery and transplantation, modern approaches to trauma patients, the use of intra-arterial chemoembolisation for liver tumours, and procedures involving percutaneous puncture of the liver have all contributed to a rising incidence of hepatic artery pseudoaneurysm. A true aneurysm is saccular of fusiform dilatation of an attery with an intact (though often attenuated) arterial wall. A pseudoaneurysm, by contrast, is a contained haematoma resulting from a defect in the wall of an artery, and its wall is formed by the surrounding structures.

The commonest complication of hepatic artery pseudoaneurysm (44%) is rupture into the peritoneal cavity. Less frequent is rupture into the common bile duct or gastrointestinal tract (mainly the duodenum). Acute upper gastrointestinal (GI) bleeding and shock are the ultimate clinical manifestations, though smaller ‘herald bleeds’ are often noted. Ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), and angiography are all useful in diagnosis.

We report a case of acute upper GI haemorrhage caused by a pseudoaneurysm of the common hepatic artery six months after blunt abdominal trauma.

Case Report

A 29-year-old African–American man was admitted to the emergency room with acute abdominal pain, fever (37.8°C), haematemesis (approximately 100 ml), and melaena. A nasogastric tube was placed and bright redn blood was drained (200 ml); the tube was then irrigated until clear. The patient appeared to be in good general health. On initial assessment, his blood pressure was 154/93 mmHg and the heart rate was 50 bpm. The abdomen was soft, slightly distended and tender in the right upper quadrant, with increased pain on deep palpation or percussion. There was no rebound tenderness, hepatomegaly or splenomegaly.

The medical history was remarkable only for a motor vehicle accident six months earlier. At that time, he was hospitalised for two days with multiple injuries, chief of which was a laceration of the left lobe of the liver with a periportal haematoma. Two months after discharge, he was seen in the clinic for abdominal pain and was sent home with pain medication. Over the next four months he had intermittent abdominal pain and black tarry stools. On the day of admission to our service, he experienced sudden, sharp epigastric pain radiating to the back, without positional relief.

His white cell count was 16.5×10⁹/L, haemoglobin was 10.3 mg/dl, haematocrit 31.6%, and platelet count 240×10⁹/L. Liver function tests were elevated, including AST 530 U/L, ALT 681 U/L, GGT 349 U/L, and total bilirubin 47 umol/1 (2.7 mg/dl); prothrombin time, partial thromboplastin time, electrolytes, blood urea nitrogen, creatinine, and amylase were normal. At upper endoscopy, 400 ml blood was aspirated from the stomach, which was otherwise normal. The pylorus was oedematous. The wall of the first portion of the duodenum appeared to be bulging with a bleeding vessel (Figure 1), which was cauterised.

Figure 1. .

Active duodenal bleeding at endoscopy.

On the day after admission, the patient was clinically stable (blood pressure 147/83 mmHg; heart rate 67 bpm) and afebrile, but he still felt abdominal pain. Nasogastric drainage was clear, but the haemoglobin had fallen to 8.9 mg/L. Abdominal ultrasound revealed a 4.0×6.25 cm hypoechoic oval mass in the hepatic hilum; flow was detectable in the mass on duplex and colour Doppler ultrasound at 50 mm/sec (Figure 2). Pseudoaneurysm was suspected, and CT confirmed the presence of an enhancing mass in the hepatoduodenal ligament (Figure 3), consistent with the diagnosis of pseudoaneurysm. The presence of a left hepatic artery arising from the left gastric artery was noted; the pseudoaneurysm was related to the common hepatic artery, which arose in the usual way from the coeliac axis. Later that day, angiography documented a pseudoaneurysm of the common hepatic artery. Arterial flow to the liver was preserved through the accessory left hepatic artery and through the proper hepatic artery distal to the pseudoaneurysm via the gastroduodenal artery (Figure 4). Based on his laboratory results, it is likely that the patient had biliary compression and cholestasis as well.

Figure 2. .

Colour Doppler ultrasound shows flow in the lesion.

Figure 3. .

CT scan shows a hypodense mass in the hepatoduodenal ligament.

Figure 4. .

Delayed filling of the pseudoaneurysm on hepatic arteriography.

At exploration, multiple adhesions were identified around the porta hepatis near the large pseudoaneurysm (Figure 5). After achieving proximal vascular control of the supracoeliac aorta, the pseudoaneurysm was opened and evacuated. The lateral defect in the common hepatic arterial wall was oversewn with 5-0 Prolene sutures, occluding the vessel; hepatic arterial flow was maintained by collaterals, as described above. Within the aneurysmal cavity, a friable, necrotic area located antero-inferiorly was found to be in communication with the duodenum. This fistula was closed with a running 4-0 Vicryl suture and was buttressed with an omental patch. The patient tolerated the procedure well; total blood loss was 300 ml.

Figure 5. .

Operative findings pseudoaneurysm (P); duodenum (D).

The postoperative course was uneventful, and the patient was discharged on postoperative day 5. At six months follow-up, he remains well.

Discussion

Arterioduodenal fistula is a rare cause of upper gastrointestinal bleeding. Most cases are secondary to abdominal aortic surgery (0.4–2.0%); less frequently, they are the result of an aortic aneurysm ². Hepatic artery aneurysm is an uncommon cause of duodenal bleeding ¹,²,³,⁵. Typically, the diagnosis is delayed because the clinical manifestations are non-specific. The most frequent complaint is right upper quadrant pain; other presentations include haemoperitoneum, abdominal mass, jaundice, and haemobilia ¹,⁴.

True hepatic artery aneurysms are usually extrahepatic (75–80%) and most commonly occur in the common hepatic artery (65%). They may be congenital or secondary to an acquired condition such as atherosclerosis or infection. Hepatic artery pseudoaneurysms are usually secondary to penetrating trauma (including operation). There is only one other reported case of hepatic artery pseudoaneurysm secondary to blunt trauma ⁶; the diagnosis in that case was also reached at a time remote from the injury.

Although it is useful to localise the site of bleeding, endoscopy is not the definitive diagnostic procedure ⁵. Ultrasound scan with Doppler should be used early as a screening method for right upper quadrant pain, and can help establish a diagnosis of pseudoaneurysm. The gold standard for diagnosis has traditionally been angiography, but improvements in CT and MR scanning are increasingly allowing for both accurate non-invasive diagnosis and precise delineation of vascular anatomy ¹,⁵,⁶ in preparation for operation.

A successful outcome in cases of enteric fistulisation from visceral aneurysms requires operation. In some cases (such as ours), vascular anatomy allows for safe ligation of the damaged vessel without reconstruction. Particularly when the proper hepatic artery is the site of injury, reconstruction is likely to be necessary to avoid ischaemic damage to the liver and bile ducts. Autogenous saphenous vein is, in our experience, the best material with which to replace the hepatic artery when primary reconstruction is not feasible.

In patients with a history of either blunt or penetrating abdominal trauma, the presence on imaging studies of a haematoma in the hepatoduodenal ligament should raise suspicion of vascular injury and should lead to tests to exclude this possibility, thus avoiding the sequelae described.