A Rare Confluence: Hepatic Artery Aneurysm and Infective Endocarditis in a Patient with a Mitral Valve Prosthesis.

Introduction: Hepatic artery aneurysm (HAA) is a rare condition, comprising only 0.1% of all arterial aneurysms, yet it is the most common visceral pseudoaneurysm with a 20% prevalence among such cases. Mycotic HAA in the context of infective endocarditis is uncommon and results from microbial invasion and arterial wall damage.

Case description: A 73-year-old woman with coronary artery disease, atrial fibrillation, repaired mitral valve prolapse and on warfarin presented with sudden left lower quadrant abdominal pain. She was hypotensive (BP 60/45 mmHg) and exhibited periumbilical tenderness. Laboratory findings included white blood cell count 18,000 cells/μl, haemoglobin 7.7 g/dl, platelets 1,023,000/μl, aspartate transferase 509 U/l, alanine transaminase 313 U/l and positive SARS-CoV-2. Non-contrast CT of the abdomen/pelvis revealed haemoperitoneum, rectus sheath haematoma and a hypodense hepatic lesion. Contrast-enhanced CT confirmed a left hepatic lobe pseudoaneurysm, supported by Doppler ultrasound. Coil embolisation of the pseudoaneurysm stabilised the patient's haemodynamics. Blood cultures grew Staphylococcus epidermidis, prompting treatment with meropenem and vancomycin due to her prosthetic mitral valve. Transthoracic echocardiogram showed valve vegetation, though a transoesophageal echocardiogram later revealed no vegetations. Follow-up imaging showed a stable thrombosed pseudoaneurysm. The patient remained stable and was transferred for mitral valve replacement. Blood cultures remained negative, but antibiotics were continued for six weeks. Warfarin was resumed without further bleeding.

Conclusion: Mycotic HAAs - though rare - can be life-threatening, especially in anticoagulated patients with prosthetic valves. They often present only upon rupture. Prompt diagnosis, vascular intervention and empirical antibiotic therapy are essential for successful outcomes.

Learning points: Hepatic artery aneurysm is a rare vascular entity that typically presents with non-specific symptoms, making early diagnosis challenging.One notable aetiology is septic embolisation resulting from infective endocarditis.