Overview
Definition:
A hepatic artery pseudoaneurysm (HAP) is a contained arterial rupture, forming a pulsatile hematoma that communicates with the artery lumen
it is not a true aneurysm as it lacks all layers of the arterial wall.
Epidemiology:
HAPs are rare, with an incidence of approximately 0.1% after liver transplantation and 0.01-0.1% after percutaneous liver biopsies
they can also occur after abdominal trauma, pancreatitis, or hepatic surgery.
Clinical Significance:
HAPs pose a significant risk of catastrophic hemorrhage, potentially leading to shock, organ ischemia, and mortality
prompt diagnosis and effective management are crucial for patient survival and preventing morbidity.
Clinical Presentation
Symptoms:
Pulsatile abdominal mass
Right upper quadrant pain, often severe and radiating to the back
Fever, suggesting infection or inflammation
Jaundice if compressing the biliary tree
Hemorrhage presenting as hematemesis, melena, or hematochezia, often massive and life-threatening
Hypotension and shock in cases of rupture.
Signs:
Palpable, pulsatile abdominal mass
Tenderness on palpation
Signs of hemorrhagic shock: tachycardia, hypotension, pallor, diaphoresis
Possible icterus if biliary compression is present.
Diagnostic Criteria:
Diagnosis is typically confirmed by imaging
clinical suspicion is high in patients with risk factors presenting with abdominal pain, a pulsatile mass, or evidence of bleeding.
Diagnostic Approach
History Taking:
Detailed history of recent abdominal trauma, liver biopsy, liver transplantation, pancreatitis, or prior abdominal surgery
Character of abdominal pain
Presence of bleeding symptoms
Fever or signs of infection
Medications, especially anticoagulants or antiplatelets.
Physical Examination:
Thorough abdominal examination to assess for masses, tenderness, organomegaly, and signs of peritonitis
Assess for hemodynamic instability
Cardiovascular examination to detect murmurs or bruits over the mass.
Investigations:
Ultrasound with Doppler: Initial modality to detect pulsatile flow and assess mass characteristics
sensitivity varies
CT Angiography (CTA): Gold standard for diagnosis, demonstrating the pseudoaneurysm, its size, location, neck, and relationship to adjacent vessels and organs
also identifies active extravasation
MR Angiography (MRA): Alternative to CTA, useful in patients with contrast allergies or renal impairment
Angiography: Diagnostic and therapeutic, allows direct visualization and immediate intervention.
Differential Diagnosis:
True arterial aneurysm
Arteriovenous fistula
Hematoma
Hepatic abscess
Pancreatic pseudocyst
Solid liver tumors with vascular components.
Management
Initial Management:
Hemodynamic stabilization with intravenous fluids and blood products if in shock or actively bleeding
Analgesia
Strict monitoring of vital signs
Broad-spectrum antibiotics if infection is suspected
Consultation with vascular surgery and interventional radiology urgently.
Surgical Management:
Historically, surgical ligation of the hepatic artery was the primary treatment for HAPs, particularly in emergent situations of uncontrolled hemorrhage
indications include failure of endovascular methods, unavailability of interventional radiology, or widespread infection
The surgical approach involves direct ligation of the affected hepatic artery proximal and distal to the pseudoaneurysm, or en bloc resection of the involved segment if the pseudoaneurysm is complex or associated with other pathology
This can be done through laparotomy or laparoscopy.
Endovascular Management:
Coil embolization is the preferred modality for most elective and semi-emergent cases
it involves percutaneous catheter-guided placement of embolic coils into the pseudoaneurysm sac or its feeding artery to occlude blood flow
Other embolization materials like cyanoacrylate glue or particles may also be used
This technique offers high technical success rates and preserves arterial patency in the majority of cases, minimizing the risk of hepatic ischemia.
Comparison Coil Vs Ligation:
Coil embolization is generally favored due to its minimally invasive nature, lower complication rates, preservation of hepatic blood flow, and faster recovery
Ligation, while definitive, carries a higher risk of hepatic ischemia, infarction, and liver failure, especially if collateral circulation is poor or if a major hepatic artery (e.g., common hepatic artery) is ligated
However, ligation remains a critical option for emergent control of hemorrhage when endovascular intervention is not feasible or has failed.
Complications
Early Complications:
Hemorrhage (rupture), hepatic ischemia, hepatic infarction, post-embolization syndrome (pain, fever, elevated liver enzymes), infection, access site complications (hematoma, pseudoaneurysm at access site).
Late Complications:
Recurrence of pseudoaneurysm, development of new pseudoaneurysms, biliary complications (strictures, necrosis), liver failure (especially after ligation), portal vein thrombosis.
Prevention Strategies:
Careful technique during procedures like liver biopsy and transplantation
Prompt recognition and management of bleeding
Judicious use of anticoagulants
Appropriate patient selection for endovascular vs
surgical intervention
Ensuring adequate collateral circulation before considering ligation.
Prognosis
Factors Affecting Prognosis:
Promptness of diagnosis and treatment
Patient's hemodynamic status at presentation
Etiology of the pseudoaneurysm
Size and location of the pseudoaneurysm
Presence of comorbidities
Success of the chosen management strategy (endovascular or surgical).
Outcomes:
With successful endovascular management, outcomes are generally good with a low rate of recurrence and morbidity
Surgical ligation carries a higher risk of complications, particularly liver failure, but is life-saving in emergent bleeding scenarios
Mortality is significant in cases of unmanaged or ruptured pseudoaneurysms.
Follow Up:
Follow-up imaging (ultrasound, CTA) is essential to confirm successful occlusion and monitor for recurrence, especially after endovascular treatment
Patients should be monitored for symptoms of hepatic dysfunction or recurrent bleeding
Long-term follow-up may be required depending on the etiology and treatment modality.
Key Points
Exam Focus:
HAPs are contained arterial ruptures
CTA is the gold standard for diagnosis
Coil embolization is preferred for its less invasive nature and better outcomes compared to ligation
Ligation is reserved for emergent hemorrhage control or when endovascular methods fail.
Clinical Pearls:
Suspect HAP in patients with unexplained abdominal pain, a pulsatile mass, or bleeding post-liver procedures or trauma
Always assess for hemodynamic stability
Consider the potential for hepatic ischemia with ligation, especially of the common hepatic artery.
Common Mistakes:
Delaying diagnosis or treatment in unstable patients
Undertreating smaller, asymptomatic pseudoaneurysms that can still rupture
Incorrectly attributing bleeding to other causes
Performing ligation without assessing collateral circulation, leading to infarction.