Abstract
BACKGROUND: Shock is a common complication of acute myocardial infarction and cardiac arrest. Internal mammary artery (IMA) injury is a rare cause of post-cardiopulmonary resuscitation (CPR) hemorrhagic shock. CASE SUMMARY: An 80-year-old woman presenting with inferior ST-segment elevation myocardial infarction underwent percutaneous coronary intervention to the left circumflex artery with intra-aortic balloon pump support after cardiac arrest treated with mechanical CPR. Persistent hypotension prompted computed tomography angiography, revealing a mediastinal hematoma with active right IMA extravasation. Urgent embolization resulted in hemodynamic stabilization and clinical recovery. DISCUSSION: This case illustrates the diagnostic challenge of persistent shock after coronary revascularization when hemodynamic instability is disproportionate to the cardiogenic component and highlights CPR-related IMA injury as a rare but life-threatening extracardiac cause. TAKE-HOME MESSAGE: Persistent hypotension after ST-segment elevation myocardial infarction revascularization should prompt evaluation for extracardiac causes of shock, including CPR-related IMA injury, a rare complication that is amenable to prompt embolization.