Near fatal stent thrombosis in an aneurysmatic RCX as first manifestation of heparin induced thrombocytopenia (HIT) without thrombocytopenia.

BACKGROUND: Thrombosis resulting from heparin-induced thrombocytopenia (HIT) occurs in about 2% of patients without a significant decrease in platelet counts. We report on such a near fatal thrombotic event caused by coronary intervention.

CASE PRESENTATION: A supposedly "completely healthy" 53-year-old patient was admitted to hospital with covered rupture of an aneurysm of the Aorta descendens. He was successfully operated on and underwent coronary angiography due to NSTEMI six days later. Immediately after intervention of a 90% RCX stenosis he developed ventricular flutter, was defibrillated, and re-angiography showed partial occlusion of the RCX stent. Lots of white thrombi could be retrieved by aspiration catheter and gave reason for a HIT without thrombocytopenia. The detection of platelet factor 4/heparin complex antibodies by immunoassay supported and the subsequent Heparin Induced Platelet Activation Assay proved this diagnosis.

CONCLUSIONS: The clinical event of an acute stent thrombosis should alarm the interventional team to the diagnosis of HIT even with a normal platelet count.