PB0809 - Performance of the ISTH-BAT bleeding score in a population of newly diagnosed VWD in the U.S. Zimmerman Program

Monday, July 11, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

Pamela A. Christopherson

Research Program Coordinator
Versiti Blood Research Institute
Milwaukee, Wisconsin, United States

Co-Author(s)

TA

Thomas Abshire

Sr. Investigator
Versiti Blood Research Institute
Milwaukee, Wisconsin, United States
Dearbhla Doherty, MB BCh BAO

Research fellow
Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
Dublin 2, Dublin, Ireland
Veronica H. Flood, MD

Associate Medical Director, Investigator
Versiti Blood Research Institute
Milwaukee, Wisconsin, United States
SH

Sandra Haberichter

Director, Hemostasis, Senior Investigator
Versiti Blood Research Institute
Milwaukee, Wisconsin, United States
JO

James S. O'Donnell, MB, PhD

Professor of Haematology
Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland,Dublin, Ireland
Dublin, Dublin, Ireland
RM

Robert Montgomery

Senior Investigator
Medical College of Wisconsin, Versiti Blood Research Institute, Children's Research Institute
Milwaukee, Wisconsin, United States

Background: Diagnosis of VWD can be challenging due to subjective bleeding assessment and variable laboratory testing.

Aims: We sought to evaluate newly diagnosed VWD subjects by analyzing VWF levels, bleeding scores and incorporating current Guidelines on the diagnosis of VWD.

Methods: Zimmerman Program Prospective Study patients referred to local hematologists and assessed for a bleeding disorder were enrolled and evaluated for VWD. 564 subjects with a new diagnosis of type 1/Low VWF were analyzed. Abnormal ISTH-Bleeding Assessment Tool (BAT) scores were determined using published age and gender cutoffs. Central VWF:Ag and VWF:GPIbM were used to divide cohort by levels of < 30, 30-50 and >50 IU/dL (normal).

Results: 346 (61%) of newly diagnosed subjects had an abnormal BAT while 218 (39%) had a normal BAT with no significant difference in gender or VWF levels between those groups. The BAT did not correlate with VWF levels but did correlate with age. Both < 30 and 30-50 groups had 35% of subjects with normal BATs, similar number of females, and no significant difference in age. When taking both levels and bleeding score into account, 201 subjects would be classified as type 1 VWD under new guidelines. Using a VWF level cutoff of 50, the sensitivity of the BAT to predict type 1 VWD was 65%, specificity 42% in all subjects. When adult women were evaluated separately, 107 (70%) had an abnormal BAT and 45 (30%) had a normal BAT with sensitivity of 73% and specificity of 33%.

Conclusion(s): While BATs are a useful tool to quantitate bleeding and assist with the diagnosis of VWD, the pediatric population, as well as patients who present with moderate to borderline VWF levels and bleeding, remain challenging. Further analysis of subject’s subsequent samples and bleeding scores will provide insight into the diagnostic accuracy of VWD and utility of a BAT in this cohort.