AML-134: Dysfunctions in Primary Hemostasis as Additional Risk Factors of Bleeding in Patients with Newly Diagnosed Acute Myeloid Leukemia (AML)

Background Bleeding events are common adverse events in newly diagnosed AML. The underlying mechanisms have not been fully investigated and need to be looked at in more depth. Objective The primary endpoints were qualitative and quantitative functions of plasma von Willebrand factor (vWF) by measuring of vWF activity (vWF:ristocetin cofactor [vWF:RCo]), vWF level (vWF:antigen [vWF:Ag]), factor VIII coagulation activity regarding vWF (vWF:FVIII), and FVIII activity (FVIII) as additional bleeding risk factors in AML patients since the diagnosis and during the first course of treatment. Patients and methods A total number of 10 patients with newly diagnosed AML (excluded APL) and 10 age-matched and sex-matched healthy individuals (control group). The severity of bleeding events was assessed according to Modified WHO Bleeding Scale. Results Four patients in the study group were experiencing bleeding events (G1-4) before and during the first course of treatment and six patients had no bleeding episodes (G0). There were no bleeding episodes in the control group (G0). Six patients with AML had levels of vWF:FVIII below normal ranges (median 29.85 %, range 20.25–40.55), four of them had different grades of spontaneous bleeding events before and during the first course of treatment. Thus, levels of vWF:FVIII below normal ranges in patients with AML was associated with higher risk of spontaneous bleeding events (p=0.019). We have monitored decreased levels of vWF:RCo in three patients with AML and similar in the control group. Three patients with vWF:RCo below normal ranges (median 26,6 %, range 22.5–72.85) in the study group had bleeding events (Grade 1-4), one of them died during the first course of chemotherapy due to gastrointestinal bleeding. Despite a similar decline in vWF:RCo below normal ranges in the control group, bleeding events have not emerged. Conclusions In our study group, decreased level of vWF:FVIII was associated with spontaneous bleeding events and may play an etiologic role in haemorrhagic complications in patients with newly diagnosed AML. The activity of vWF can be a promising risk factor of spontaneous bleeding combined with vWF:FVIII and vWF:Ag in newly diagnosed AML.