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.