The Role of Abnormal Hemostasis and Fibrinolysis in Morbidity and Mortality of Acute Promyelocytic Leukemia

Despite the improved therapeutic advances in the management of acute promyelocytic leukemia (APL), a significant early mortality during induction, also referred to as early death (ED), remains an obstacle for further improvement in outcome. Hemorrhagic complications are the most common cause of morbidity and mortality. Perturbed hemostatic dysfunction is present as the result of abnormalities in both the coagulation and the fibrinolytic systems. The activation of coagulation is distinct from the classical disseminated intravascular coagulation. Multiple abnormalities in the fibrinolytic system have recently been identified. The most significant change is increased production of tissue plasminogen activator (tPA) and its receptor annexin A2 by the APL promyelocytes. Among the hemorrhagic complications, intracranial hemorrhage predominates. The pathogenesis of this catastrophic event is elucidated by new evidence of adverse effect of tissue plasminogen activator (tPA) on the brain, including both the plasmin-dependent and plasmin-independent pathways. In order to address the hemorrhagic complications, a thorough understanding of the hemostatic dysfunction is essential. In this article, our current concept of the abnormal hemostasis in APL is reviewed. The failure to reduce the early death rate, despite the introduction of effective therapy, will also be discussed.