Hepatic artery, Pseudoaneurysm, Stent-graft

72-year-old man

A 72－year－old man was admitted to our hospital with a small amount hematochezia and vague abdominal pain. At presentation, his abdomen was mildly distended and bowel sounds were decreased. His body temperature was 36.5°C, pulse rate 118/min, respiration rate 20, and blood pressure 110/70 mmHg. However, his blood pressure decreased abruptly to 40/30mmHg about two hour later with aggravated abdominal pain. Emergency endoscopy showed that a mix old and fresh blood filled the gastric lumen, but we could not find the bleeding site, and the patient complained of aggravated abdominal pain concomitant with an abrupt reduction in vital signs. Exploration was undertaken and duodenotomy was performed under the suspicion of a duodenal ulcer with active bleeding. During the operation, a suspicious extrinsic compression lesion was observed at the medial wall of the duodenal bulb. Postoperatively, the patient was stable for a short time only, and then continuous massive bleeding along the drainage site was noted.

A Ruptured hepatic artery pseudoaneurysm

Multi-detector computed tomography (MDCT) of the abdomen with intravenous contrast and arterial phase 3D reconstruction showed a 5cm diameter aneurysm with an inner thrombotic lining in the hepatic artery(Fig. 1).

Fig. 1 A 72-year-old man with proper hepatic artery pseudoaneurysm. A-E Contrast-enhanced axial CT scans (A, B) and coronal reformated image (C) oblique maximal intensity projection (D) and volume rendering (E) images during the arterial phase demonstrate large hepatic artery pseudoaneurysm at the hepatic artery.

Fig. 1 A 72-year-old man with proper hepatic artery pseudoaneurysm. A-E Contrast-enhanced axial CT scans (A, B) and coronal reformated image (C) oblique maximal intensity projection (D) and volume rendering (E) images during the arterial phase demonstrate large hepatic artery pseudoaneurysm at the hepatic artery.

Fig. 1 A 72-year-old man with proper hepatic artery pseudoaneurysm. A-E Contrast-enhanced axial CT scans (A, B) and coronal reformated image (C) oblique maximal intensity projection (D) and volume rendering (E) images during the arterial phase demonstrate large hepatic artery pseudoaneurysm at the hepatic artery.

Fig. 1 A 72-year-old man with proper hepatic artery pseudoaneurysm. A-E Contrast-enhanced axial CT scans (A, B) and coronal reformated image (C) oblique maximal intensity projection (D) and volume rendering (E) images during the arterial phase demonstrate large hepatic artery pseudoaneurysm at the hepatic artery.

Fig. 1 A 72-year-old man with proper hepatic artery pseudoaneurysm. A-E Contrast-enhanced axial CT scans (A, B) and coronal reformated image (C) oblique maximal intensity projection (D) and volume rendering (E) images during the arterial phase demonstrate large hepatic artery pseudoaneurysm at the hepatic artery.

Emergency angiography was performed and demonstrated the 5cm sized aneurysm sac with a short, wide neck and with a waist, originating from the superior aspect of the proper hepatic artery. Portal venous flow was intact. Endovascular coil embolization was tried, but the sac was large and the neck short and wide, and coils floated freely within the sac, suggesting the high possibility of migration. So, the intervention radiologist planned and deployed a 7mm x 4cm stent-graft at the origin of the aneurysm(Fig. 2). Control angiogram demonstrated complete exclusion of the aneurysm without leakage. After procedure, the patient was stable and no bleeding sign was noted. FU CT scan one week later showed a thrombosis－filled aneurysm without any communicating flow(Fig. 3).

Fig. 2 A-B. Selective angiography demonstrates the5cm sized bilobed aneurysmal sac with a short, wide neck originating from the superior aspect of the proper hepatic artery.

Fig. 2 A-B. Selective angiography demonstrates the5cm sized bilobed aneurysmal sac with a short, wide neck originating from the superior aspect of the proper hepatic artery.

C-D The 7mm x 4cm stent-graft are successfully deployed at the origin of the aneurysm

C-D The 7mm x 4cm stent-graft are successfully deployed at the origin of the aneurysm

Fig. 3 A-B. FU contrast-enhanced axial CT scan and oblique maximal intensity projection image one week later showed a thrombosis-filled aneurysm without any communicating flow and good maintenance of stent-graft at proper hepatic artery.

Fig. 3 A-B. FU contrast-enhanced axial CT scan and oblique maximal intensity projection image one week later showed a thrombosis-filled aneurysm without any communicating flow and good maintenance of stent-graft at proper hepatic artery.

Hepatic artery pseudoaneurysms are rare and potentially life－threatening vascular disorders. Hepatic artery pseudoaneurysm rupture occurs in 76% of patients and mortality among patients requiring operative intervention is 75% (1). Hepatic artery pseudoaneurysms have been reported to occur as a complication of injury to the hepatic artery, e.g., due to trauma, a blunt or penetrating abdominal injury (about 1.2%), or inadvertent surgical injury during laparoscopic cholecystectomy (0.2%~0.8%), OLT (orthotropic liver transplantation), or radical hepatopancreatobiliary operations. They have also been reported in chronic pancreatitis patients and have been reported occasionally in patients with arteriosclerosis, cystic medial necrosis, polyarteritis nodosa (PAN), necrotizing vasculitis, acute pancreatitis, or hepatocellular carcinoma. Hepatic artery pseudoaneurysm can also occur as an complication of OLT (0.8%~2%)(2, 3). In these cases, aneurysmal sites are usually at the hepatic arterial anastomosis, and these can be classified as intrahepatic or extrahepatic, according to location. Intrahepatic aneurysms are usually related to previous procedures, such as, liver biopsy and percutaneous transhepatic biliary drainage, and may be accompanied by associated arterioportal shunts. Extrahepatic aneurysms have a different pathogenesis from the intrahepatic form, and the most important risk factor has been reported to be local sepsis. The most common presentation is hypotension due to abdominal hemorrhage. However, the clinical presentation of hepatic artery pseudoaneurysm may be asymptomatic, and symptoms vary from patient to patient just before rupture, e.g., unexplained fever or biliary colic, or laboratory analysis may produce abnormal liver function tests. Sometimes they are found incidentally during routine examinations performed to screen for possible postoperative vascular complications, which suggests that routine imaging is important for hepatic artery pseudoaneurysm detection in radical and aggressive pancreatobiliary tumor surgery and OLT patients. Contrast－enhanced CT is a minimally invasive technique that can easily be performed in emergency cases, without preparation, particularly in cases with massive gastrointestinal bleeding. Multi－detector CT provides dramatically faster scan acquisitions and improves spatial resolution by reducing collimation and by allowing multi－planar reconstruction, which can allow the extent of the lesion and its relations with adjacent structures to be determined (2, 4). On CT scans, an aneurysm typically manifests as a round focal lesion of high attenuation that is almost identical to major arterial structures in early phase contrast－enhanced CT scans. Super－selective micro－coil embolization is recognized as an effective treatment in patients with an extrahepatic aneurysm of the hepatic arteries, with a post－operative mortality of 25% and a post－embolization mortality of 14% (5). The liver can tolerate considerable arterial embolization without significant consequences because of its multiple collateral pathways. However, inadvertent occlusion of the wrong vessel and subsequent infarction of normal structures and abscess formation are well－known complications associated with transcatheter embolization. Implantation of a stent－graft to exclude a visceral aneurysm has previously been described in patients that have developed a false aneurysm after Whipple’s operation (6, 7), after LT(8), or that have developed hepatic artery pseudoaneurysm after chronic pancreatitis (9). The use of a covered stent is indicated for a hepatic artery pseudoaneurysm in a patient with a compromised liver blood supply due to portal vein occlusion or where collateral pathways from the gastroduodenal artery are excluded. Most of the published case reports are of technical successes, and the described case was also successfully managed. The present case was not of a vascular compromised patient, but in this case the bleeding was massive and the aneurismal neck was short and wide. In addition, the sac was relatively large size and complex in shape. Coil embolization was initially tried, but many coils would have been needed and the distal segment could not be approached with coil due to the waist portion and the migration of coil is highly suspected, and thus, the intervention radiologist decided that stentgraft application was the more favorable option in this case. Stent－graft implantation in a visceral artery is not always possible due to the tortuous anatomy and post－interventional anticoagulation therapy. Additionally, placement of a stent－graft in an infected area can provoke late graft disintegration and consequently aneurysmal rupture. In summary, hepatic artery pseudoaneurysm is relatively infrequent, but rupture rates are high and fatal. The stenting of hepatic artery pseudoaneurysm offers a reasonable alternative to embolization and surgery. However, long－term data regarding the use of stent－grafts in visceral vessels are extremely limited. Nevertheless, we expect that, with continued follow－up, further improvements in stent－graft design, and increased operator experience that stent－grafts will become a valuable therapeutic option for the treatment of hepatic artery pseudoaneurysm.

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