Abstract 15274: STEMI as Initial Manifestation of Essential Thrombocythemia

Abstract

Background: Essential thrombocythemia (ET) is a myeloproliferative neoplasm of myeloid cell expansion, mainly excessive platelet production, associated with thrombotic complications. Myocardial infarction (MI) in the setting of ET can result from thrombosis in the absence of coronary atherosclerosis. Here we present a case of ST elevation MI in the setting of previously undiagnosed ET. Case Report: A 59-year-old male with hypertension presented to the ED with left upper extremity weakness which started upon waking. On exam, he was in acute distress and diaphoretic. EKG revealed sinus rhythm with ST elevation in II, III, aVF, V5, and V6 suggesting inferolateral STEMI (Figure 1A). Labs were notable for Hgb 8.5g/dL, white blood cell count 33k/μL, and platelets 1.9million/μL. Decision Making: He was loaded with aspirin and clopidogrel (dual antiplatelet therapy-DAPT) and taken for coronary angiogram which revealed 80-90% thrombotic occlusion of the left circumflex artery (Figure 1b). Thrombectomy was performed and a drug-eluting stent was placed. A bone marrow biopsy showed JAK2 positive ET with myelofibrosis. He was immediately started on hydroxyurea. Platelets remained elevated, thus pegylated IFN alpha-2a was started which normalized platelet count. He remained on DAPT through discharge with no recurrent ischemic events or in-stent thrombosis during the 45-day hospitalization post stent placement. Conclusion: Patients with ET are at high risk for arterial thrombosis regardless of the presence of traditional atherosclerotic risk factors. High-risk patients, which includes those age over 60 with JAK2 mutation or history of arterial thrombosis, should be treated prophylactically with aspirin and hydroxyurea for cytoreduction. MI may be the first clinical manifestation of ET, even in patients without atherosclerotic risk factors. Initial management in patients with ET presenting with STEMI includes PCI with DAPT and early cytoreductive therapy.