Occult haemorrhagic shock due to hemomediastinum following percutaneous coronary intervention: a case report.

BACKGROUND: Mediastinal haematoma is a rare complication following percutaneous coronary intervention (PCI) with challenging diagnosis and potential life-threatening consequences. CASE SUMMARY: This report documents the case of an 87-year-old woman who underwent PCI for in-stent restenosis of the proximal left circumflex artery. One hour after the procedure, the patient developed signs of shock such as dyspnoea, hypotension, and altered mental status. Initial evaluation, including physical examination, electrocardiography, and transthoracic echocardiography, was negative. Subsequent computed tomography (CT) angiography revealed a mediastinal haematoma and active bleeding of the right thyrocervical artery. After urgent successful embolization, haemodynamics stabilized, and recovery was uneventful. DISCUSSION: This case highlights the importance of considering rare (iatrogenic) bleeding sources as a potential cause of shock after coronary angiography or PCI and its diagnostic pitfalls. Prevention relies on meticulous guidewire manipulation with continuous fluoroscopic visualization while advancing when hydrophilic guidewires are required in challenging anatomies.