Von Willebrand Disease in Taiwan: A Clinical and Laboratory Studies of 52 Patients.

Von Willebrand disease (VWD) has been found to be the most common inherited bleeding disorder in Caucasian with a prevalence of around 1%, yet it has not been well recognized in Taiwan and Asian countries. Only a small number of patients have been identified and reported. The aim of this retrospective study was to identify patients with VWD by clinical manifestation and laboratory tests in Taiwan. VWD was detected by a panel of laboratory tests, including bleeding time, aPTT, factor VIII activity assay, Von Willebrand antigen (VWF: Ag) and ristocetin cofactor activity (VWF: RCo), and platelet function analyzer (PFA) test using both Collagen/ADP and Collagen/Epinephrine (CEPI). VWF multimer analysis was performed by western blot to confirm the disease subtype. From October, 2003 to April, 2007, 52 of 494 (9.5%) patients, from 44 families, were identified to have VWD, including 16 men and 36 women. Their median age was 29 with a range of 4∼69 years of age. The most frequently encountered reasons for VWD detection was menorrhagia accounting for 19.2%. The others included inherited detection because of affected family (11.5%), prolonged aPTT (11.5%), excessive bleeding after dental procedures (9.6%) and excessive bleeding after surgery or invasive procedure (9.6%). By laboratory tests, the mean value of VWF: Ag and VWF: RCo was 46.9 ± 18.4% and 32.3 ± 17.4%, respectively. The most sensitive test was VWF: RCo with 90.3%, followed by CEPI with 83.8%. Of 37 patients with VWF multimer analysis, 34(92%) were revealed to have type I VWD, 1 had type IIA, and 2 from the same family had type III VWD. In conclusion, our study demonstrated that VWD was not an uncommon inherited bleeding disease in Taiwan. Menorrhagia was the most common reason for VWD determination, and VWF: RCo and PFA test CEPI were the more sensitive tests for the VWD identification.