Anticoagulation combined with cytoreduction may best lower risk for recurrent venous thromboembolism (VTE) in patients with myeloproliferative neoplasms (MPNs), according to results of a systematic review published in Blood Advances.

Risk of thrombosis is increased in patients with myeloproliferative neoplasms (polcycythemia vera, essential thrombocythemia, and primary myelofibrosis). Antithrombotic therapy with or without cytoreduction can reduce risk of recurrent VTE; however, clinical practice regarding long-term management is diverse and optimal strategies are unknown.

In this study, researchers from University of Amsterdam searched publication databases through February of 2020 for articles on management of thrombotic events and recurrent VTE in patients with MPNs. Their systematic review and meta-analysis included 10 nonrandomized observational studies comprising a total of 1295 patients.

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During follow-up, 22.6% of the patients with VTE had recurrent thrombotic events; but few studies defined whether recurrent events were arterial or venous thrombosis. Risk for recurrence was high among patients treated with only anticoagulants: vitamin K antagonists alone, 29.2% (21 of 72 patients), or direct oral anticoagulants alone, 21.4% (3 of 14 patients).

Antiplatelet therapy with cytoreduction resulted in reduced recurrent events in 7 studies (18.6% of 452 patients), similar to what was observed for anticoagulants with cytoreduction in a pooled analysis of 8 studies (16.0% of 376 patients). Specifically, recurrence rates for vitamin K antagonist and direct oral anticoagulant only were higher than for either anticoagulant type combined with cytoreduction (36.8% vs 17.6% and 21.4% vs 7.9%, respectively).

In 5 studies with a total of 53 patients, antiplatelet, anticoagulation, and cytoreduction triple therapy had similar rates of recurrence (24.3%; 9 of 37 patients) as antiplatelet and anticoagulant combination without cytoreduction (25.0%; 4 of 16 patients).

In 6 studies involving 134 patients treated with cytoreduction only or no antithrombotic/cytoreductive treatment, cytoreduction alone had comparable recurrence rates (30.7%) as no therapy (36.4%).

Among reported bleeding events, most were observed among patients receiving antiplatelet therapy with or without oral anticoagulation (60%). Survival rates were overall high (93%). Among deaths, only 19% (15 of 77 patients) were related to thrombotic events.

This review was based on studies that were judged to have high confounding factors and selection biases. However, these findings suggest long-term use of oral anticoagulants with cytoreduction best decreased risk for VTE recurrence in patients with MPNs.

Disclosure: Multiple authors declared affiliations with and/or received funding from the pharmaceutical industry. Please refer to the original article for a full list of disclosures.


Hamulyák EN, Daams JG, Leebeek FWG, et al. A systematic review of antithrombotic treatment of venous thromboembolism in patients with myeloproliferative neoplasms. Blood Adv. 2021;5(1):113-121. doi:10.1182/bloodadvances.2020003628