Multimodal imaging follow-up of a left main trunk pseudoaneurysm presenting with cardiopulmonary arrest

Coronary artery pseudoaneurysms (PsAs) involving the left main trunk (LMT) are exceptionally rare. Among them, spontaneous LMT PsAs without prior percutaneous coronary intervention are particularly uncommon and pose significant diagnostic and therapeutic challenges.

A 58-year-old man on chronic haemodialysis presented with fever and chest discomfort. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in blood cultures, and empirical antibiotics were initiated to treat presumed acute pericarditis. He experienced cardiopulmonary arrest on hospital Day 9 and was resuscitated with veno-arterial extracorporeal membrane oxygenation. Emergency coronary angiography revealed a large LMT PsA and severe calcific ostial stenoses of the left anterior descending and intermediate arteries. Intravascular ultrasound demonstrated vascular wall disruption by the PsA cavity. Drug-eluting stents were implanted in both branches under mechanical circulatory support. Due to prohibitive surgical risk, conservative therapy with prolonged antibiotics was chosen. Serial coronary computed tomography (CT) revealed transient expansion of the PsA, followed by gradual regression over time. He was later discharged but subsequently underwent coronary artery bypass grafting for in-stent restenosis.

This case highlights a rare occurrence of spontaneous LMT PsA in a patient with active MRSA infection. Although surgical resection is generally preferred, conservative management may be appropriate in selected high-risk patients. Multimodal imaging-including initial coronary angiography and intravascular ultrasound, serial CT for size monitoring, and follow-up angiography at recurrence-played a central role in anatomical assessment and therapeutic decision-making. Careful longitudinal evaluation with appropriate imaging tools is essential for safe and individualized management in such complex scenarios.