von Willebrand factor and factor VIII levels after desmopressin are associated with bleeding phenotype in type 1 VWD.

The bleeding phenotype of patients with type 1 von Willebrand disease (VWD) is very heterogeneous. We hypothesized that this heterogeneity may partly be explained by variability in response of von Willebrand factor (VWF) and factor VIII (FVIII) levels to stress during hemostatic challenges. We therefore investigated whether VWF and FVIII levels after administration of desmopressin, which mimic in vivo hemostatic response during hemostatic challenges, explain the heterogeneity in bleeding phenotype of patients with type 1 VWD. We performed a retrospective cohort study in 122 patients with type 1 VWD. All patients received a test dose of desmopressin shortly after diagnosis. Patients' mean age was 47 ± 14 years, and the mean Tosetto bleeding score was 10 ± 7. Higher FVIII activity during the complete time course after desmopressin administration (1, 3, and 5-6 hours), and higher VWF and FVIII levels combined at 3 hours after desmopressin administration, were associated with a lower bleeding score: β = -0.9 (-1.7; -0.1) and β = -1.2 (-1.9; -0.5), respectively, adjusted for age, sex, body mass index (BMI), and comorbidities. Patients with FVIII activity in the highest quartile 3 hours after desmopressin administration had a much lower bleeding score compared with patients in the other 3 quartiles (β = -5.1 [-8.2; -2.0]) and also had a lower chance of an abnormal bleeding score (odds ratio = 0.2 [0.1-0.5]), both adjusted for age, sex, BMI, and comorbidities. In conclusion, VWF and FVIII levels after desmopressin administration, which mimic hemostatic response to hemostatic challenges, are associated with the bleeding phenotype of patients with type 1 VWD. This may partly explain the variability in bleeding phenotype of these patients.