ABC | Volume 114, Nº4, Suplement, April 2020

Case Report Acute Myocardial Infarction as First Onset of Polycythemia Vera Caroline Ferreira da Silva Mazeto Pupo da Silveira, 1 Lívia Beatriz Santos Limonta Vitali, 1 Fabiana Garcia Faustino, 1 Alejandra Del Carmen Villanueva Maurício, 1 Renato Teixeira, 1 Silméia Garcia Zanati Bazan 1 Universidade Estadual Paulista Júlio de Mesquita Filho - Faculdade de Medicina de Botucatu (UNESP), 1 Botucatu, SP - Brazil Introduction Polycythemia vera (PV) is a chronic clonal progressive myeloproliferative neoplasmcharacterizedby an absolute increase in erythrocytes and, usually, leukocytosis, thrombocytosis, and splenomegaly. Its incidence rates around 2.8/100,000 people per year. 1 Diagnosis is confirmed using the criteria defined by the 2016 revised World Health Organization (WHO) guidelines.² Major criteria include hemoglobin levels over 16.5 and 16.0 g/dL or hematocrit over 49 and 48% inmen and women, respectively, or increased red cell mass of more than 25%above themean normal predicted value; bonemarrowbiopsy showing hypercellularity for age with trilineage growth; presence of JAK2V617F or JAK2 exon 12 mutation. A minor criterion is reduced serum erythropoietin level. Diagnosis requires meeting either all 3 major criteria or 2 major criteria and the minor criterion. The patient is also considered as at thrombosis risk; those aged over 60 or with thrombosis history are considered at considered high risk; if both risk factors are absent, low risk is considered. Treatment includes cytoreductive drugs, such as hydroxyurea, antiplatelet agents and therapeutic sangrias. Thrombosis is a major cause of morbidity and mortality in PV patients. These thrombotic events are most frequently microcirculatory and arterial.² Acute myocardial infarction (AMI) in myeloproliferative diseases is mostly attributed to coronary thrombosis due to hyperviscosity and thrombocytosis. The risk is increased in the presence of cardiovascular risk factors. 3 Coronary events are common during the follow-up of PV, with a rate of 11.4% in 10-year follow-up in the literature. 4,5 Also, in recent studies, arterial thrombotic events were more common than venous thrombotic events when diagnosed shortly before the PV diagnosis. However, the first presentation of PV as AMI is considered rare, with fewer than 10 cases in the literature. 3, 6-15 Case Report Patient was a 68 years-old white male, regularly treating hypertension, without any previous history of thrombotic events. He presented at the emergency room with an unspecific malaise, without chest pain or dyspnea, numbness in the proximal portion of both arms. He was admitted hemodynamically stable with good oxygen saturation. At physical examination, he had a plethoric face and dullness to percussion over Traube’s space. Due to the likelihood of atypical presentation of acute coronary syndrome, he was initially investigated with an electrocardiogram (ECG) and myocardial necrosis markers (MNM), blood cell count and kidney function. The rest ECG (Figure 1a) showed pathologic Q wave and inversion of T wave in DII, DIII and aVF, later evolving (Figure 1b) with elevation of the ST segment in DII, DIII and aVF, while the other characteristics were maintained. MNM came positive (CK-MB from 34 to 36 ng/mL; reference <16 ng/dL and troponin from 0.12 to 0.81 and then to 1.07 ng/mL; reference <0.01 ng/mL). Pulmonary embolism was ruled out due to negative D-dimer. Other laboratorial analysis showed normal renal function and hemoglobin 21.3 g/dL, hematocrit 65.4%, platelets 805,000/mm 3 (reference: 140,000–440,000/mm 3 ), thus characterizing hyperviscosity, macroplatelets and leucocytes 15,400/mm 3 (reference: 4,000–11,000/mm 3 ), mainly neutrophils. It also showed no lipids or glucose alterations. The patient was diagnosed with AMI caused by PV and, against what is mostly found in the literature, the AMI diagnosis came prior to the discovery of PV. He was classified as at high thrombosis risk due to his age and double anti-platelet therapy was initiated with AAS (loading dose of 300 mg plus 100 mg/day) and clopidogrel (loading dose of 300 mg plus 75 mg/day), as well as enoxaparin 1 mg/kg twice a day. As observed in Figure 1, ST elevation was less than 1 mm. Also, the symptoms did not get worse as the ECG changed, so the team opted for weighing the benefit-risk ratio regarding submitting a possible non ST segment elevation AMI or even a non-reperfused ST segment elevation AMI to angiography under a high hematocrit situation. He was then submitted to 3 therapeutic sangrias before the coronary angiography (Figure 2A and 2B) could be performed safely, showing absence of angiographic evidence of intra-coronary thrombus and aneurysmatic dilatation in the median portion of the right coronary artery and no abnormalities or obstructions in the left anterior descending coronary artery or circumflex artery. The patient had TIMI 3 flow grade in the right coronary, circumflex and left anterior descending arteries (Figure 2B). There is no information on TIMI frame count. Physiology assessment of the arteries was not available in the service. Even though no thrombus was found, as this may have been caused by treatment prior to angiography, and due to the lack of another hypothesis, we sustained the diagnosis of type 2 AMI. Echocardiogram showed preserved systolic function with an ejection fraction of 64% (Teichholz), mild diastolic dysfunction (E/A ratio of 1.0, E/e’ ratio of 8.67) and no alteration of left ventricular contractility. The AMI area was viewed on cardiac magnetic Mailing Address: Silméia Garcia Zanati Bazan • Universidade Estadual Paulista Júlio de Mesquita Filho - Faculdade de Medicina de Botucatu - UNESP - Cardiologia Distrito Rubião Jr, s/n. Postal Code 18618-687, Botucatu, SP – Brazil E-mail: sgzanati@fmb.unesp.br Manuscript received February 24, 2019, revised manuscript July 23, 2019, accepted August 18, 2019 Keywords Myocardial Infarction; Polycythemia Vera, Thrombocytosis; Myeloproliferative Disorders. DOI: https://doi.org/10.36660/abc.20190104 27