Case Report: Heparin-induced thrombocytopenia leads to acute myocardial infarction post-PCI in multi-vessel coronary artery disease.

Heparin-induced thrombocytopenia (HIT) is a rare but severe complication of heparin therapy, characterized by a significant reduction in platelet count and a paradoxical prothrombotic state, which increases the risks of both arterial and venous thrombosis. This case report describes a 58-year-old male patient with multi-vessel coronary artery disease who developed acute ST-segment elevation myocardial infarction (STEMI) following successful percutaneous coronary intervention (PCI). Despite initial successful revascularization, the patient experienced recurrent chest pain, and HIT was clinically suspected based on a significant drop in platelet count and the 4Ts scoring system, though confirmatory anti-PF4/heparin antibody testing was unavailable at our institution. Treatment with corticosteroids was initiated; however, following transfer to another hospital, the patient received platelet transfusion-a contraindicated intervention in HIT-and subsequently succumbed to a fatal arrhythmic event. This case highlights the diagnostic and therapeutic challenges of suspected HIT in PCI patients, where it may mimic other post-procedural complications such as stent thrombosis. It underscores the critical need for vigilant monitoring of platelet counts, timely access to confirmatory diagnostic testing, immediate initiation of guideline-recommended non-heparin anticoagulants, and seamless communication during inter-hospital transfers to prevent potentially harmful interventions and improve patient outcomes.