Platelet-dependent von Willebrand factor activity in acute myeloid leukemia patients: role in hemostatic alterations

Background Patients with acute myeloid leukemia (AML) may suffer from bleeding tendency, which can aggravate their pre-existing condition. Bleeding in these patients occurs mainly because of thrombocytopenia, disseminated intravascular coagulopathy, and platelet dysfunction. However, other underlying mechanisms are complex and are not completely understood. Von Willebrand factor (vWF) defects have been implicated as contributors to bleeding complication. Aim The study aimed to investigate the pattern of vWF– ristocetin cofactor (RCO) activity in newly diagnosed AML patients and its relation to therapy, to explore its potential role in the prevalent phenomenon of bleeding in AML patients, in order to correlate between vWF–RCO activity and other hemostatic parameters and known prognostic factors in AML. Patients and methods Thirty newly diagnosed patients with AML and 20 healthy age-matched and sex-matched individuals (the control group) were studied. The vWF– RCO activity using the platelet agglutination method was determined on plasma samples of both patients and controls. Results Our results showed significantly reduced vWF–RCO activity in AML patients at diagnosis, which significantly increased 2 weeks after treatment. Our study proposes the following cutoffs for vWF–RCO: less than or equal to 85.2% for predicting AML patients prone to bleeding manifestations and less than or equal to 82.6% for the prediction of bad outcome. Conclusion In AML, vWF–RCO activity at diagnosis represents a valuable prognostic marker for predicting bleeding complication and bad outcome, and the provided cutoffs for vWF–RCO activity represent the first steps for its use as a bleeding predictor and prognostic marker, although future studies with larger series of patients may be needed before it can be incorporated into routine use.