Acute ST-segment elevation myocardial infarction with EDTA-dependent pseudothrombocytopenia: a case report and literature review

Abstract Background:Acute ST-segment elevation myocardial infarction (STEMI) has a rapid onset and high mortality which should be diagnosed quickly after admission and given reperfusion treatment as soon as possible. Meanwhile, antiplatelet and anticoagulant therapy play an important role in the treatment of acute myocardial infarction. Pseudothrombocytopenia has been rarely reported. This paper reports a STEMI patient with delayed reperfusion treatment due to EDTA-dependent pseudothrombocytopenia, and provides suggestions on how to identify EDTA-dependent pseudothrombocytopenia, so as to avoid the wrong withdrawal of antiplatelet drugs and the delay of reperfusion treatment in patients with acute myocardial infarction complicated with pseudothrombocytopenia. Case presentation: An 82-year-old male patient with a medical history of hypertension was admitted to the emergency department (ED) complaining of worsening chest discomfort. ST-segment elevation was noted in the leads V1-V4 and T-wave height tip on the electrocardiogram (ECG) in the ED. The cardiac biomarkers tests at ED revealed that his high-sensitivity troponin level (cTnI) was 0.25ng/L (reference interval:＜0.01ng/mL), and the serum creatine kinase-MB(CK-MB) level was 17.22ng/mL (reference interval:＜5ng/mL), and myoglobin level was 126.02ng/mL (reference interval:＜50ng/mL). Unexpectedly, his initial platelet count with a standard EDTA tube was 18 × 109 /L, and he did not receive reperfusion therapy and any fibrinolytic drug or heparin because of thrombocytopenia. Echocardiogram demonstrated regional hypokinesia of left ventricle. She received bone marrow puncture and platelet antibody examination. Subsequently, platelet clumps were seen in bone marrow blood smears and platelet antibody tests were negative. Blood collection in the heparin tube reveals an accurate platelet count of 166×109/L.However,it was been a week after his admission, he refused the operation and was discharged with the medication after his condition improved. Conclusions: Thrombocytopenia will bring risks and challenges to the reperfusion treatment of acute ST-segment elevation myocardial infarction. Clinician should be alert to EDTA-dependent pseudothrombocytopenia especially complicated with myocardial infarction. Seeking possible evidence of pseudothrombocytopenia is in favor of early diagnosis which may prevent unnecessary examination as well as over-treatment and especially mismanagement of patients in potentially life-threatening clinical conditions