Thrombotic and hemorrhagic events in 2016 World Health Organization-defined Philadelphia- negative myeloproliferative neoplasm

BACKGROUND/AIMS: Recent changes in the diagnostic criteria for myeloproliferative neoplasms (MPNs) and increasing patient numbers necessitate updating of the data on vascular events in patients with such disorders. METHODS: In this single-center study, thrombotic and hemorrhagic events were retrospectively analyzed in patients diagnosed with essential thrombocythemia (ET), polycythemia vera (PV) prefibrotic/early primary myelofibrosis (pre-PMF), or PMF, based on the 2016 World Health Organization diagnostic criteria. RESULTS: Of a total of 335 consecutive patients (139 ET, 42 pre-PMF, 124 PV, and 30 PMF patients; 192 males and 143 females) of median age 64 years (range, 15 to 91), 112 (33.4%) experienced a total of 126 thrombotic events before diagnosis, at the time of diagnosis, or during follow-up over a median of 4.6 years (range, 0.1 to 26.5). Cerebrovascular thrombosis (18.8%) was the most common initial event, followed by coronary heart disease (10.1%) and splanchnic (1.5%) and peripheral thrombosis (1.5%). Arterial thrombosis was more common than venous thrombosis (31.3% vs. 2.1%, respectively; p = 0.001). Thrombosis was most frequent in PV patients (39.5%), followed by patients with pre-PMF (38.1%), ET (30.9%), and PMF (13.3%). Of the 112 patients who experienced thromboses, 53 (47%) and 39 (33.9%) had thrombotic events before and at the time of MPN diagnosis, respectively. Twenty-seven patients (8.1%) experienced 29 hemorrhagic events, of which gastrointestinal bleeding (n = 20) was the most common. CONCLUSIONS: Most thrombotic events occurred before or at the time of diagnosis, and the prevalence of arterial thrombosis was markedly higher than that of venous thrombosis in patients with MPN.