Mohammed Al-Sadawi¹, Michael Haddadin¹, Violeta Capric¹, Samy I. McFarlane^1,

Heparin induced thrombocytopenia (HIT) is serious disorder that occurs in a small percentage of patients following exposure to heparin. HIT can further be classified into two types: HIT type 1 and type 2. Type 2 HIT is a potentially life threatening with clinically significant outcomes. It presents with thrombocytopenia and evidence of thrombus formation in the presence of antibody formation. Additionally, several variations of HIT exist, including delayed onset HIT and refractory HIT, known collectively as autoimmune HIT (aHIT). Here we present a case of delayed onset and refractory HIT in a patient with little heparin exposure, discovered only after cardiac intervention for suspected STEMI. Significant thrombotic events occurred thereafter, including radial artery stenosis and intracardiac thrombus. Treatment with argatroban was ineffective. Significant resolution of thrombocytopenia was seen several weeks after infusion with IVIG, thus depicting further suspicion for refractory HIT. IVIG for aHIT treatment is traditionally chosen only if the disease process is refractory to other anticoagulation efforts due to the potential risk for increasing thrombotic risk with IVIG infusion. Our case illistrate the rare presentation of aHIT and the use if IVIG to successfully treat thrombocytopenia in refractory HIT.

heparin-induced thrombocytopenia, radial artery occlusion, coronary intervention complications