Acute myocardial infarction caused by delayed heparin-induced thrombocytopenia and acute immunoreaction due to re-exposure to heparin in a systemic lupus erythematosus patient with HIT antibodies

A case of ST elevation myocardial infarction secondary to heparin-induced thrombocytopaenia with thrombosis

A 54 year-old woman with Noonan Syndrome presented with an acute anterolateral ST elevation myocardial infarction two weeks post septal myectomy and heparin exposure, on the background of known normal coronary arteries. Coronary angiography revealed acute thrombosis of the left main, left anterior descending and left circumflex arteries, which was successfully treated by percutaneous coronary intervention with overlapping bare metal stents. A positive heparin induced platelet antibody test and dramatic fall in platelet count confirmed the diagnosis of heparin induced thrombocytopaenia with thrombosis (HITTS) as the underlying diagnosis. This represents the first documented case of HITTS induced left main coronary artery thrombosis and occlusion.