PB0295 - Centralized diagnosis of von Willebrand disease in Russia: 5 years study results.

Background: The diagnostic capabilities of detecting von Willebrand disease(VWD) are limited in many regions of our country, and therefore, in 2019, the Russian Hemophilia Society starts the centralized diagnostics program(Program) that provides for distance diagnosis of VWD in the regions.

Aims: To evaluate the results of 5-year work centralized program for VWD diagnostics.

Methods: According to clinical state of the patient and to the decision of hematologist the patient was enrolled in Program. Blood samples were collected from peripheral vessel, then freezed and transported to the Laboratory of clinical hemostasis at the Pediatric National Medical Research Center . There were 512frozen samples from 375children and 139adult patients from 21regions of Russian Federation, received during the period 2019-2023. The concentration of antigen(vWF:Ag) and ristocetin-cofactor activity of von Willebrand factor(vWF:RCo), as well as the activity of coagulation factor VIII(FVIII) were evaluated in all samples.

Results: Preanalytical errors were detected in 42(8,2%) samples. The most common preanalytical errors were hemolysis(40,5%) and clot(35,7%). The decrease in vWF:RCo within 30-50% was detected in 14% of cases, vWF:RCo less than 30% also in 10,2% of cases. The vWF:Ag concentration was normal in 10(19,2%) patients with vWF:RCo < 30%. Among patients with vWF:RCo < 30% type1 vWD was detected in 12(23%) patients, type2-in 33(63,5%) patients, type 3–in 7(13.5%) patients. The decrease in FVIII activity while vWF:Ag and vWF:RCo were in normal range was observed in 16(4,6%) cases. In one woman with a low level of FVIII was established subtype 2N vWD(vWF:FVIIIB-2%(N:70-130%)). The centralized diagnostics program allowed to reveal the hemostasis pathology in 125(24.4%) patients. The 10.2% had the typical laboratory pattern of vWD, and 44(18.6%) patients require the additional diagnostics using an expanded panel of laboratory tests.

Conclusion(s): This program provides for complex vWD diagnostics in sparsely populated regions of the country, where it is economically impractical to create a regional diagnosis on site.