The pathogenesis and management of the coagulopathy of acute promyelocytic leukaemia

Coagulopathy occurs in most patients with (APML) and is life-threatening; therefore prompt diagnosis and recognition of any coagulation defect is imperative. Unfortunately haemorrhage remains a major cause of early death, preventing some from reaching treatment. The coagulopathy is caused directly or indirectly by the leukaemic cells through expression of activators of coagulation and fibrinolysis, proteases and cytokine generation, compounded by failure of platelet production due to marrow invasion. At presentation the predominant feature is usually hyperfibrinolysis. Since the introduction of all-trans retinoic acid (ATRA), patient outcome has dramatically improved; yet, haemorrhagic complications remain the most frequent cause of mortality. Thrombotic complications occur but are less well recognized and potentially underreported. Supportive measures and prompt initiation of ATRA currently represent the mainstay of treatment of the coagulopathy in patients with suspected APML, but unanswered questions remain as to the optimal approach to further decrease the associated haemorrhagic and thrombotic risks. In particular, it is unclear how to best predict and monitor the coagulopathy; whether there is a role for the early use of antifibrinolytics; the most appropriate trigger for giving fibrinogen replacement and the value of low-dose anticoagulation to suppress coagulation activation once fibrinolysis has been suppressed.