Acute Coronary Syndrome in Essential thrombocythemia: Usefulness of Optical Coherence Tomography

Abstract

Essential thrombocythemia is a rare myeloproliferative neoplasm, characterized by platelet proliferation with quantitative and qualitative alterations. Patients suffering from this condition are more likely to have thrombosis and hemorrhages. It has an incidence of 1 to 2.5 new cases per 100,000 inhabitants per year, (1, 2) and its frequency increases with age, with a 2:1 ratio in favor of women. (3) One of the complications of essential thrombocythemia is coronary thrombosis, which can be potentially fatal. The incidence of acute coronary events with this hematology-oncology disease is 9.4%, with a rate of fatal and non-fatal thrombotic events of 1.9 per 100 patients/year. (4) We report the case of a 35-year old female patient with thrombocythemia under study and no cardiovascular history, who presented with moderate, oppressive chest pain lasting 20 minutes, in functional class IV. Physical examination showed the patient was hemodynamically stable, with blood pressure of 110/60, heart rate of 60 bpm, and no signs of heart failure. The electrocardiogram revealed sinus rhythm without conduction disorders, narrow-QRS with 0.5 mm transient ST segment elevation (lasting < 20 minutes) from V1 to V3. Lab tests reported hematocrit 37%, hemoglobin 13 mg/dl, white blood cells 5500/mm3, and platelets 1,200,000/mm3. Ultrasensitive troponin was requested, with negative value: 5 pg/ml (normal <14 pg/ml). JAK2 was negative, Leyden factor V was negative, lupus anticoagulants were negative, and bone marrow puncture revealed megakaryocytic hyperplasia consistent with chronic myeloproliferative neoplasm. Coronary CT angiography showed lack of filling in proximal anterior descending artery causing 80% luminal obstruction, possibly indicative of thrombus or soft plaque (Figure 1A). The patient was started on anticoagulation with unfractionated heparin and aspirin 100 mg/day. The patient coursed asymptomatic for angina, and a coronary angiography was performed at 72 hours of admission, which showed no significant obstructions (Figure 1B); the study was completed with an optical coherence tomography (OCT) that revealed atherosclerotic fibrolipid plaques in the anterior descending artery at the proximal and middle-third levels (Figure 2A), and an image consistent with plaque rupture (fissure) at the proximal third level in the origin site of the first diagonal branch (Figure 2B). Due to findings in the catheterization study, atorvastatin 80 mg/day was added to the previous treatment. Echocardiography showed no motility disorders. Left ventricular systolic function was normal, with no relevant valve diseases. The patient made good progress with no further chest pain, platelet reduction (450,000/mm3 on discharge), and no changes suggestive of necrosis in the electrocardiogram. The patient was discharged 7 days after admission, continuing with aspirin 100 mg/day, anticoagulation with enoxaparin 80 mg/12 hours, atorvastatin 80 mg/day, and hydroxyurea 2000 mg/ day. Essential thrombocythemia is a condition that may present as an acute coronary syndrome, due to thrombotic events that affect the epicardial coronary arteries. It is a life-threatening complication. (5) No cases have been described in the literature in which the pathophysiological mechanism of the acute coronary syndrome (in young patients with low risk Fig. 1. A. Multislice CT-scan image showing 80% obstruction in the proximal third of the anterior descending artery. b. Coronary angiography image showing anterior descending artery with no significant lesions.