PB0835 - Comparison of bleeding symptoms and global haemostatic tests (ROTEM and clot wave form analysis) in type 3 VWD and mild/moderate Haemophilia A with similar levels of Factor VIII

Background: Type 3 von Willebrand disease (VWD) is a rare autosomal recessive disorder, characterized by undetectable levels of von Willebrand factor (VWF) and reduced levels of Factor VIII, usually less than 10%. There are similarities in bleeding symptoms between Haemophilia A (HA) and type 3 VWD due to simultaneous FVIII deficiency. There are only a few studies which have compared Rotational thromboelastometry (ROTEM) in type 3 VWD patients

Aims: To compare the clinical features, ROTEM and APTT clot waveform (APTT-CW) parameters in type 3 VWD patients with mild/moderate HA patients with FVIII between 1-10 IU/dL.

Methods: The study included 61 cases of type 3 VWD and 71 cases of mild/moderate HA with FVIII 1-10% who came for evaluation between January 2019 to December 2022. Final diagnosis was made after correlating with history and laboratory tests including bleeding time, Platelet Function Analyser, APTT, Factor VIII, Ristocetin cofactor assay, Von Willebrand antigen (VWF:Ag). ROTEM was done by modified EXTEM using diluted tissue factor.

Results: There was no significant difference in APTT and FVIII levels between type 3 VWD and HA. The ISTH BAT score was higher in children with type 3 VWD than HA, however no difference was seen in adults. Frequency of epistaxis and cutaneous bleeds was higher in type 3 VWD, while muscle hematomas and hemarthrosis was more in HA. Clotting time (CT) was lower (p=0.02) and alpha angle higher (p=0.02) in type 3 VWD than HA even with similar Factor VIII levels. The maximum acceleration, min2 was significantly higher in HA (p=0.001).

Conclusion(s): Although the Factor VIII levels were similar in type 3 VWD and HA groups, CT prolongation in ROTEM in type 3 VWD was lower than HA, which correlated with the reduced frequency of deep bleeds (muscle hematomas and hemarthrosis) in type 3 VWD.