Abstract Number: PB0946
Meeting: ISTH 2021 Congress
Background: von Willebrand Disease (vWD) is a bleeding disorder caused by a lack of, or a functional abnormality of von Willebrand Factor (vWF). The United Kingdom Haemophilia Centre Doctors Organisation (UKHCDO) published 2014 guidelines for categorising patients by disease type.
Aims: We aimed to re-evaluate the classification of a cohort of patients, diagnosed with von Willebrand disease in NHS Grampian from 1980 onward, by applying the 2014 guidance to both existing and updated measurements of vWF and Factor VIII. We also assessed changes in vWF levels across time in patients with and without features of degenerative vascular disease.
Methods: Using pre-existing patient data on the UKHCDO registry, patients were reclassified using the 2014 guidelines. In addition, updated factor levels were also collected and reclassification using these updated levels was performed.
Results: 49 patients were included and 57% of them were reclassified. Most changes in diagnosis were seen in patients who were initially diagnosed with Type 1 vWD, and none occurred in patients with Type 3 vWD. 5 patients were reclassified into the category of having ‘low vWF level’ introduced in 2014. 21 patients were deemed to no longer have vWD.
Most were shown to have increases in vWF antigen (vWF:Ag) and vWF:Ristocetin cofactor activity (vWF:RCo) across time. However, in patients with vascular disease, there was no obvious trend in these factor level changes based on a small number of data.
Conclusions: Using the criteria outlined in the 2014 UKHCDO guidelines resulted in the reclassification of over half of the patients in our study. Reclassification into ‘low vWF level’ and increasing levels of vWF with age/cardiovascular risk account for most of the changes observed. There has to be clear thinking on the need to change vWD diagnosis based on increases in vWF related to age/cardiovascular disease.
To cite this abstract in AMA style:Watson H, Ng YE. Reclassification of von Willebrand Disease Classification and Effects of Vascular Dysfunction on von Willebrand Factor [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/reclassification-of-von-willebrand-disease-classification-and-effects-of-vascular-dysfunction-on-von-willebrand-factor/. Accessed September 24, 2021.
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