Introduction
Acute leukemia in pediatric patients can present with bleeding symptoms such as bruising, petechiae and epistaxis secondary to thrombocytopenia, endothelial cell injury, abnormal fibrinolysis, disseminated intravascular coagulation (DIC), or inherited bleeding disorders such as von Willebrand disease or clotting factor deficiencies(1). Bleeding, along with thrombosis, in acute promyelocytic leukemia (APL) has been attributed to augmented fibrinolysis via increased expression of tissue plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA), leading to generation of plasmin and degradation of fibrin(2). Enhanced fibrinolysis, in addition to thrombocytopenia and DIC, leads to the bleeding diathesis seen in these patients.
Abnormal coagulation screening in pediatric patients diagnosed with leukemia include prolonged prothrombin time (PT) and/or activated partial thromboplastin time (aPTT), which are common at presentation. These abnormalities generally require further work up due to the need for rapid diagnostic procedures (such as a lumbar puncture and bone marrow aspirate and/or biopsy), along with central venous line (CVL) placement for initiation of chemotherapy. Abnormal coagulation screening tests requiring further work up can lead to delays in procedures due to concerns of bleeding. There is also a tendency to achieve correction of the PT/aPTT using fresh frozen plasma (FFP) and/or vitamin K, in the hope of preventing bleeding during the procedure, which is not evidence-based.
A systematic review by Liontos et al(3) did not find evidence of utility of routine pre-operative coagulation testing to predict perioperative bleeding with different types of procedures. However, given the complex interplay of factors involved in the leukemia population, it is unclear if abnormal screening coagulation tests, in the absence of significant bleeding, increase bleeding risk. Even more unclear is the utility of correcting these abnormal values using blood products to prevent peri-procedural bleeding. Therefore, the aim of this study was to assess if there was a correlation between prolonged PT/aPTT and bleeding symptoms or other laboratory parameters measured at initial leukemia diagnosis, with the goal of reassessing the need for work up of these abnormal results to justify use of blood products to correct laboratory values.