Abstract
Thrombotic events are very frequent and represent the main cause of morbidity and
mortality in patients with Philadelphia chromosome–negative myeloproliferative neoplasms
(MPNs), mainly polycythemia vera and essential thrombocythemia. Pathogenesis of blood
clotting activation in these diseases is multifactorial, and it involves various abnormalities
of platelets, erythrocytes, and leukocytes, as well as dysfunctions of endothelial
cells. These include not only elevations in the counts of circulating blood cells,
arising from the clonal proliferation of hematopoietic progenitor cells, but also
modifications of several physiological/molecular properties. Patients with MPN can
be stratified in “high-risk” or “low-risk” thrombotic categories according to the
age and history of thrombosis. The most commonly used front-line drugs for the treatment
of high-risk patients include hydroxyurea and interferon alpha, whereas in low-risk
patients, primary antithrombotic prophylaxis with aspirin is used. Future research
should be focused on the evaluation of the role of biomarkers in identifying MPN patients
at higher risk of thrombosis, who may benefit from primary thromboprophylaxis. Finally,
a better understanding of the molecular events leading to the progress of the hypercoagulable
state in MPN patients may provide appropriate tools for the development of targeted
therapies based on reversal of coagulopathy.
Keywords
myeloproliferative neoplasms - thrombosis - risk factors
