Department of Haematology, Imperial College Healthcare, National Health Service Trust, London, United Kingdom.
Department of Haematology, Imperial College London, London, United Kingdom.
Semin Thromb Hemost. 2019 Sep;45(6):604-611. doi: 10.1055/s-0039-1693477. Epub 2019 Aug 5.
Chronic myeloproliferative neoplasms (MPN) are characterized by clonal expansion of an abnormal hematopoietic stem/progenitor cell and include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Venous thrombosis, often at unusual sites, including splanchnic vein thrombosis and arterial thrombosis, as well as a hemorrhagic tendency and a propensity to transform into myelofibrosis or acute leukemia are common complications in patients with MPNs. The pathogenesis of thrombosis in MPN patients is complex and multifactorial. Disease related factors, such as an increase in blood cell counts (i.e., leukocytosis, erythrocytosis, and thrombocytosis), and more importantly presence of mutation can interact with non-disease patient related factors such as age, previous history of thrombotic events, obesity, hypertension, hyperlipidemia, and presence of thrombophilic defects. The overall rate of recurrent thrombosis after venous thromboembolism (VTE) is 6.0 to 6.5 per 100 patient-years in patients with MPN compared to 2.7 to 3.7 per 100 patient-years in patients without MPN, and antithrombotic therapy with vitamin K antagonists (VKAs) is associated with a clear benefit, reducing the incidence of recurrence by 48 to 69%. Life-long oral anticoagulation with VKAs is the cornerstone of the antithrombotic treatment for splanchnic vein thrombosis (SVT). Patients with MPN-related cerebral venous thrombosis (CVT) should also be treated with long-term anticoagulation with VKAs. The role of direct acting oral anticoagulants in patients with thrombosis and MPN is not established and the use of these anticoagulants should be considered on an individual basis according to the risk of recurrent of VTE and bleeding.
慢性骨髓增殖性肿瘤（MPN）的特征是异常造血干细胞/祖细胞的克隆性扩张，包括真性红细胞增多症（PV）、原发性血小板增多症（ET）和原发性骨髓纤维化（PMF）。静脉血栓形成，常发生在不常见的部位，包括脾静脉血栓形成和动脉血栓形成，以及出血倾向和向骨髓纤维化或急性白血病转化的倾向，是 MPN 患者的常见并发症。MPN 患者血栓形成的发病机制复杂且多因素。与疾病相关的因素，如血细胞计数增加（即白细胞增多、红细胞增多和血小板增多），更重要的是突变的存在，可与非疾病相关的患者因素相互作用，如年龄、既往血栓事件史、肥胖、高血压、高血脂和存在血栓形成倾向缺陷。与无 MPN 的患者相比，MPN 患者静脉血栓栓塞（VTE）后复发性血栓的总体发生率为每 100 患者年 6.0 至 6.5 次，而每 100 患者年 2.7 至 3.7 次，抗血栓治疗用维生素 K 拮抗剂（VKAs）可带来明显的益处，将复发率降低 48%至 69%。长期口服 VKAs 是治疗脾静脉血栓形成（SVT）的抗血栓治疗基石。MPN 相关脑静脉血栓形成（CVT）患者也应长期用 VKAs 抗凝治疗。直接作用的口服抗凝剂在血栓形成和 MPN 患者中的作用尚未确定，应根据 VTE 和出血的复发风险，个体化考虑使用这些抗凝剂。
