The Approach to Thrombosis Prevention across the Spectrum of Philadelphia-Negative Classic Myeloproliferative Neoplasms

Abstract

Patients with myeloproliferative neoplasm (MPN) are potentially facing diminished life expectancy and decreased quality of life, due to thromboembolic and hemorrhagic complications, progression to myelofibrosis or acute leukemia with ensuing signs of hematopoietic insufficiency, and disturbing symptoms such as pruritus, night sweats, and bone pain. In patients with essential thrombocythemia (ET) or polycythemia vera (PV), current guidelines recommend both primary and secondary measures to prevent thrombosis. These include acetylsalicylic acid (ASA) for patients with intermediate- or high-risk ET and all patients with PV, unless they have contraindications for ASA use, and phlebotomy for all PV patients. A target hematocrit level below 45% is demonstrated to be associated with decreased cardiovascular events in PV. In addition, cytoreductive therapy is shown to reduce the rate of thrombotic complications in high-risk ET and high-risk PV patients. In patients with prefibrotic primary myelofibrosis (pre-PMF), similar measures are recommended as in those with ET. Patients with overt PMF may be at increased risk of bleeding and thus require a more individualized approach to thrombosis prevention. This review summarizes the thrombotic risk factors and primary and secondary preventive measures against thrombosis in MPN.