The effects of plasma viscosity in thromboembolic events among patients with essential thrombocytosis: A case-control study

INTRODUCTION: Essential thrombocythemia (ET) is an entity of classic Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), characterized by thrombocytosis with megakaryocytic hyperplasia where in the thrombocytes are increased with abnormal function. Thrombotic events are seen frequently and represent the main cause of morbidity and mortality in patients with MPNs, mainly polycythemia vera and ET. This study has aimed to research the effects of clonally increased thrombocytes on plasma viscosity (PV) levels among patients with ET and the relationship between PV and thromboembolism history, according to the hypotheses about the effects of PV in thromboembolic events among patients with ET. METHODS: A total of 55 patients were enrolled in the study group, 18 of who had been newly diagnosed with ET according to 2016 World Health Organization criteria and had not previously been treated. 37 of them had already been diagnosed with ET and had been treated. There were 47 healthy volunteers in the control group. 5 cc blood samples were taken from the patients into tubes including an anticoagulant to measure their PV levels. RESULTS: PV of the control group was found to be lower than in the study group and both each patient groups (p <0.05). No relationship was found between the patient groups in terms of PV (p = 0.404). The mean PV levels of the 16 patients with a history of thromboembolism and the 39 patients with no such history were 2.42 +/- 0.17 cP and 2.33 +/- 0.20 cP, respectively. The mean PV levels were found to be similar according to their history of thromboembolism in all patient groups and in treated patients (p = 0.572 vs p = 0.991). CONCLUSION: We have found that PV levels were increased in clonally increased thrombocytes in patients with ET when compared with the control group. This is the first study in this field according to our knowledge.