Keywords
dissecting aneurysm - computed tomography - melena - hepatoduodenal fistula - pseudoaneurysm
- common hepatic artery
Introduction
A true aneurysm is saccular or a fusiform dilatation of an artery with a proper arterial
wall. A pseudoaneurysm, by contrast, is a contained hematoma resulting from a defect
in the wall of an artery, with the wall formed by surrounding structures. The most
common site of hepatic artery aneurysms is the common hepatic artery (CHA). Atherosclerosis
and other congenital and degenerative processes are the common causes of hepatic artery
aneurysms. Abdominal trauma, percutaneous interventional techniques, transarterial
chemoembolization of liver tumors, vascular surgery, and liver transplantation are
the reasons for the increasing occurrence of hepatic pseudoaneurysms. The most common
presentation of hepatic artery pseudoaneurysm is rupture into the peritoneal cavity
with less frequent presentations of rupture into the gastrointestinal tract (mainly
the duodenum) and, very rarely, into the common bile duct. The clinical picture varies
from acute upper gastrointestinal (GI) bleeding and shock to smaller herald bleeds.[1] Here, we report the case of an acute upper GI hemorrhage manifesting as melena,
caused by a dissecting aneurysm of the common hepatic artery, in the absence of abdominal
trauma, with formation of a hepatic arterioduodenal fistula.
Case Report
A 54-year-old chronic alcoholic male and binge drinker, without any known chronic
illnesses, metabolic syndrome, or past abdominal surgeries or trauma, presented to
the emergency department with a 1-week history of intermittent melena, associated
with postural symptoms for 1 day. Clinical examination was significant for hypotension
(mean arterial pressure 60 mm Hg), tachycardia and pallor with diaphoresis without
significant abdominal signs. Blood investigations showed anemia (hemoglobin 8.6 g/L,
normal 13–16 g/L), increased lactate (5.6 mmol/L, normal < 1 mmol/L), and preserved
renal and liver function tests. Upper GI endoscopy revealed an ulcerated mass in the
second part of the duodenum with an inferior opening separate from the mass. A computed
tomographic (CT) angiography of the abdomen revealed a large dissecting aneurysm of
the common hepatic artery with a thrombosed false lumen ([Fig. 1A], arrow) compressing and displacing the pyloric region. A fistula was noted between
the thrombosed false lumen and second part of the duodenum ([Fig. 1B], arrow). A tight stenosis ([Fig. 1C], thick arrow) was noted at the ostium of the common hepatic artery, with the dissecting
aneurysm ([Fig. 1C], thin arrow) extending distally up to just proximal to the hepatic artery bifurcation.
The gastroduodenal artery was not visualized, with tiny inferior pancreaticoduodenal
branches noted supplying the hepatic artery near the bifurcation. A multidisciplinary
team recommended management via interventional radiology techniques. A conventional
celiac axis angiogram via a 5F Simmons catheter revealed a 4.2 × 2.9-cm pseudoaneurysm
arising from the CHA ([Fig. 2A], arrow). The CHA was cannulated with a 2.8F Progreat microcatheter (Terumo; Tokyo,
Japan), and the distal end of the aneurysm was embolized with two interlock coils
(Boston Scientific, Marlborough, MA) and two pushable coils (Cook Medical, Bloonington,
IN) ([Fig. 2B], thick arrow). Thereafter, a 14-mm × 50-cm interlock coil was deployed into the
aneurysmal sac. The microcatheter was gently pulled back into the stenosed CHA ostia,
and stability was assessed. This was followed by an injection of glue and Lipiodol
mixture (1:1) to seal the ostia ([Fig. 2B], thin arrow). Celiac axis angiogram showed no filling of the pseudoaneurysm ([Fig. 2C]). On follow-up imaging after 14 days, complete obliteration persisted and the hepatic
artery branches were seen filling via inferior pancreaticoduodenal arcade ([Fig. 1D], arrows). The patient remained well.
Fig. 1 CT angiography of the abdomen showing a large dissecting aneurysm of the common hepatic
artery with thrombosed false lumen (A, arrow) compressing and displacing the pyloric region, and communicating with the
second part of the duodenum (B, arrow) associated with a tight stenosis of CHA ostia (C, thick arrow) with the dissecting aneurysm extending distally up to the hepatic arterial
bifurcation (C, open arrow); postinterventional treatment follow-up imaging showing complete obliteration
of aneurysm and intrahepatic arterial collateral circulation (D, arrows).
Fig. 2 Celiac axis angiogram showing a large pseudoaneurysm of common hepatic artery (A, arrow) with postembolization angiogram (B, C) showing distal occlusion of aneurysm with coils (B, thick arrow) and glue Lipiodol plug (B, thin arrow) at the mouth of the aneurysm and no residual aneurysm filling (C).
Discussion
Aneurysms of the celiac axis (4% of visceral aneurysm) are rare and mostly associated
with congenital diseases, atherosclerosis, fibromuscular dysplasia, vasculitis, trauma,
or segmental arterial mediolysis—a nonarteriosclerotic, noninflammatory arteriopathy,
most commonly found in abdominal arteries. Spontaneous dissection, most often seen
with the superior mesenteric artery of the celiac trunk, is uncommon and presents
clinically with acute or chronic abdominal pain.[2] Hepatic artery aneurysmal dissection presents mostly as deranged liver function
or hemoperitoneum with hypovolemic shock. Involvement of the hepatic artery in the
form of pseudoaneurysm secondary to isolated dissection of the common hepatic artery
is still rarer. Hepatic artery pseudoaneurysms commonly occur secondary to arterial
trauma, intra-abdominal or retroperitoneal inflammation or malignancy, and manipulation
of the biliary tract. The noniatrogenic causes encompass trauma, acute and chronic
pancreatitis, arteriosclerosis, polyarteritis nodosa (PAN), necrotizing vasculitis,
infection, and hepatocellular carcinoma, all of which were ruled out in our patient.[3] However, as seen in our patient, chronic dissection of the common hepatic artery
leading to arterioduodenal fistula presenting as melena is very unusual and not reported
previously.[4] In cases of dissecting visceral artery aneurysms, the most common treatment modality
offered was surgery, but with immediate mortality approaching 5%. In our patient,
early diagnosis and nonsurgical, endovascular management proved beneficial with excellent
outcomes in the short term, without need for surgical management.[5]
Conclusion
We present the case of a 54-year-old man, a chronic alcoholic who presented to the
emergency department with intermittent melena, in whom common hepatic artery dissecting
pseudoaneurysm leading to arterioduodenal fistula was found to be the cause, managed
immediately with interventional radiology techniques. In cases of melena that are
difficult to diagnose through traditional means, early imaging and interventional
management can prove beneficial and improve short-term survival.
