ABC | Volume 114, Nº4, Suplement, April 2020

Case Report Silveira et al. Acute myocardial infarction in polycythemia vera Arq Bras Cardiol 2020; 114(4Suppl.1):27-30 infarction: the coronary aneurysmand the PV itself, both of which can contribute to the formation of thrombus and AMI. The mechanisms through which PV would lead to vascular events are not yet well established. However, some hypotheses have been displayed in literature, such as overproduction of thromboxane A2, endothelial dysfunction and platelet and leukocyte activation. 16 Elevation of leukocyte count occurs in 50 to 60% of PV patients, which may also have a detrimental effect on microcirculation in PV. Activated leukocytes may release proteases and oxygen radicals that alter endothelial cells and platelets in order to favor the development of a prothrombotic state. Platelet-leukocyte aggregates are increased in number in PV and are associated with increased propensity of thrombosis. In addition, the prothrombotic state in PV has been attributed to an acquired resistance to the naturally occurring anticoagulant— protein C—which is associatedwith reduced levels of protein S². In agreement with that statement, our patient had an increase not only in platelet but also in leukocyte count, mainly neutrophils, without any signs of infection, although that could also correspond to the AMI inflammation process. Another interesting finding in the literature is that thrombotic events might happen even when hematocrit and platelet levels are acceptable ,17 indicating that the physician should be alert to that differential diagnosis even in controlled diseases. In conclusion, this is a rare case of first onset of PV as AMI, interestingly with lack of obstruction in the angiography, indicating a possible resolution of the thrombus after antiplatelet therapy. The challenge in those cases remains Figure 2 – A. Coronary angiography. Frame showing the right coronary with aneurysm, 8.0-mm wide and 16.2-mm long; B. Coronary angiography. Frame showing the left anterior descending coronary artery TIMI 3 flow; C. Cardiac magnetic resonance imaging. Frame showing late gadolinium enhancement in the apical inferior segment, ischemic pattern. the therapy in patients with sustained obstruction, once stent placing might mean a higher risk of subsequent occlusion due to the patient’s susceptibility to form platelet thrombi. Author contributions Conception and design of the research: Silveira CFSMP; Acquisition of data: Silveira CFSMP, Vitali LBSL, Faustino FG, Maurício ADCV; Analysis and interpretation of the data: Silveira CFSMP, Vitali LBSL, Faustino FG, Maurício ADCV, Teixeira R, Bazan SGZ; Writing of the manuscript: Silveira CFSMP, Vitali LBSL, Faustino FG, Maurício ADCV, Teixeira R; Critical revision of the manuscript for intellectual content: Bazan SGZ. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associatedwith any thesis or dissertationwork. Ethics approval and consent to participate This article does not contain any studies with human participants or animals performed by any of the authors. 29