Results of a World Wide Survey On the Diagnostic Dilemma Between Type 2B Von Willeband Disease and the PT-VWD.

Abstract 4436

The Canadian PT-VWD project (www.pt-vwd.org) initiated in 2007 is based on a molecular diagnostic approach to differentiate between type 2B VWD and its closely similar disorder PT-VWD. Recruitment of worldwide samples and data still poses a challenge partly because of the relative rarity of the two bleeding disorders and more importantly because it is dependant on the level of awareness about the requirements for the differential diagnosis and the subsequent impact on the treatment decision. The objective of this survey was to gather an opinion from the worldwide hemostasis community about this diagnostic dilemma and the current utilization of the appropriate diagnostic tests. The survey comprised eight key questions (see link on website) sent individually by email to hematologists from different countries and representing a variety of academic centres. Out of 60 emails we received 37 responses. The highest response was from Europe 16/37 followed by USA 9/37. Other responses were from Africa (3), Canada (2), Asia (2), Middle East (2), South America (1), Mexico (1) and Australia (1). Fifty four percent of specialists have seen or diagnosed 1-5 type 2B VWD cases and 38% have seen or diagnosed 1-5 PT-VWD cases. 82% have reported they have access to laboratory phenotypic tests including RIPA and/or platelet mixing studies with only 59% reporting they have access to genetic testing of the two responsible genes: VWF and platelet GP1BA gene. Genetic analysis was the most discriminative test in the opinion of 54% and the RIPA was chosen to be the discriminative test by 35% while 11% believed the appropriate discrimination should be based on both. 84% agreed to classify PT-VWD under platelet function disorders and 73% have felt that PT-VWD should be investigated when platelet function defects are suspected. On a scale from 1-10 with 10 being most important, 30/37 of participants reported 7-10 to rate the importance of this diagnostic dilemma and 13% have reported 5. Despite the relatively small number of respondents, the data obtained through this survey confirm the rarity of the two disorders, reflects the positive world-wide opinion re the diagnostic challenges of the two closely similar disorders and indicate the significant unavailability of genetic analysis as a useful confirmatory test.