Overview
Definition:
A hepatic artery pseudoaneurysm is a pulsatile hematoma that forms adjacent to an artery due to a breach in the arterial wall, typically caused by trauma or iatrogenic injury
Ligation involves surgically or endovascularly occluding the feeding artery to prevent rupture and hemorrhage.
Epidemiology:
Hepatic artery pseudoaneurysms are rare, accounting for less than 1% of all visceral artery aneurysms
Common causes include blunt abdominal trauma, penetrating trauma, liver biopsy, biliary procedures, pancreaticoduodenectomy, and hepatic artery chemoembolization
They are more common in males.
Clinical Significance:
Hepatic artery pseudoaneurysms pose a significant risk of rupture, leading to life-threatening intra-abdominal hemorrhage
Prompt diagnosis and management are crucial to prevent mortality and morbidity
Understanding their etiology, presentation, and treatment options is vital for surgical residents preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Patients may present with abdominal pain, often severe and localized to the right upper quadrant
Hemorrhage can manifest as hematemesis, melena, hematochezia, or signs of hypovolemic shock including hypotension, tachycardia, pallor, and syncope
Some may be asymptomatic, discovered incidentally.
Signs:
Physical examination may reveal a pulsatile abdominal mass, tenderness, or guarding
Signs of hemorrhagic shock include hypotension, tachycardia, tachypnea, and altered mental status
Auscultation may reveal a systolic bruit over the aneurysm.
Diagnostic Criteria:
Diagnosis is primarily made through imaging
Definitive diagnosis requires demonstration of a saccular or fusiform dilatation communicating with the hepatic artery, containing flowing blood, on angiography or cross-sectional imaging
Clinical suspicion coupled with abnormal imaging findings confirms the diagnosis.
Diagnostic Approach
History Taking:
A detailed history should focus on recent abdominal trauma, invasive procedures (liver biopsy, surgery, angiography, chemoembolization), or conditions predisposing to arterial wall weakness
Ask about any history of bleeding or abdominal pain.
Physical Examination:
A thorough abdominal examination is essential, palpating for masses, assessing for tenderness, rigidity, and guarding
Assess vital signs for hemodynamic instability
Examine for signs of external trauma or surgical scars.
Investigations:
Contrast-enhanced computed tomography angiography (CTA) is the gold standard for initial diagnosis, providing excellent visualization of the aneurysm, its origin, size, and relationship to surrounding structures, as well as the presence of active bleeding
Doppler ultrasonography can identify pulsatile flow
Digital subtraction angiography (DSA) is both diagnostic and therapeutic, allowing for immediate embolization
Laboratory tests include complete blood count, coagulation profile, and liver function tests.
Differential Diagnosis:
Differential diagnoses include true hepatic artery aneurysm, arteriovenous fistula, ruptured gallbladder, peptic ulcer disease with gastrointestinal bleeding, ruptured liver cyst, hepatocellular carcinoma with hemorrhage, and other intra-abdominal masses.
Management
Initial Management:
Immediate resuscitation is paramount in hemodynamically unstable patients
This involves aggressive fluid resuscitation, blood transfusion, and correction of coagulopathy
Hemodynamic monitoring and urgent surgical or interventional consultation are critical.
Medical Management:
Medical management is primarily supportive, focusing on hemodynamic stabilization and preparation for definitive treatment
Anticoagulation is generally contraindicated due to the risk of hemorrhage
Definitive treatment is almost always required.
Surgical Management:
Surgical ligation is indicated for symptomatic pseudoaneurysms, those at high risk of rupture (e.g., large size > 3 cm, rapid growth), or when endovascular treatment fails or is not feasible
The procedure involves proximal and distal ligation of the feeding hepatic artery branches
Hepatectomy may be necessary for very large or infected pseudoaneurysms, or when significant hepatic parenchyma is involved.
Endovascular Management:
Endovascular embolization via DSA is the preferred first-line treatment for many hepatic artery pseudoaneurysms due to its minimally invasive nature and high success rates
Coils, thrombin, or sclerosing agents are used to occlude the pseudoaneurysm and feeding artery
Selective embolization of the feeding artery is crucial to avoid ischemia to the liver parenchyma.
Postoperative Care:
Postoperative care includes hemodynamic monitoring, pain management, and prophylaxis against infection
Surveillance imaging (CTA or ultrasound) is performed to confirm exclusion of the pseudoaneurysm and assess for patency of remaining hepatic artery supply
Liver function should be monitored.
Complications
Early Complications:
Hemorrhage or re-bleeding despite treatment, hepatic ischemia or infarction, caval injury during catheterization, pulmonary embolism from embolic agents, and infection.
Late Complications:
Recurrence of pseudoaneurysm, development of new pseudoaneurysms, intrahepatic abscess formation, and development of portal hypertension or liver dysfunction in cases of significant vascular compromise.
Prevention Strategies:
Careful technique during invasive procedures, particularly liver biopsy and chemoembolization
Meticulous surgical technique
Careful patient selection for interventional procedures
Close post-procedural monitoring for early detection of complications.
Prognosis
Factors Affecting Prognosis:
The main determinant of prognosis is the occurrence and severity of rupture
Prompt and successful treatment of unruptured pseudoaneurysms generally leads to good outcomes
Factors influencing outcomes include patient's hemodynamic stability at presentation, size and location of the pseudoaneurysm, and the success of the chosen treatment modality.
Outcomes:
With timely diagnosis and effective treatment (surgical ligation or endovascular embolization), the prognosis for hepatic artery pseudoaneurysms is generally favorable, with low mortality rates for unruptured lesions
Ruptured pseudoaneurysms have a higher mortality risk.
Follow Up:
Patients require regular clinical and radiological follow-up to ensure complete resolution of the pseudoaneurysm, monitor for recurrence, and assess for any late complications
The duration and frequency of follow-up depend on the initial treatment and patient's condition.
Key Points
Exam Focus:
Etiology of hepatic artery pseudoaneurysms (trauma, iatrogenic)
Diagnostic modalities (CTA, DSA)
Management options: endovascular embolization vs
surgical ligation
Indications for each
Complications of rupture and treatment.
Clinical Pearls:
Suspect hepatic artery pseudoaneurysm in any patient with abdominal pain, unexplained GI bleeding, or hemodynamic instability following abdominal procedures or trauma
CTA is essential for diagnosis
Endovascular embolization is often the first-line treatment.
Common Mistakes:
Delaying diagnosis in suspected cases
Inadequate resuscitation in bleeding patients
Embolizing hepatic artery branches without ensuring adequate collateral supply to the liver, leading to ischemia
Failing to adequately exclude the pseudoaneurysm during endovascular procedures.