Von Willebrand’s disease is a common, congenital bleeding disorder. Which of the following statement(s) is/are true concerning Von Willebrand’s disease?

c. Screening laboratory tests will include a prolonged aPTT with a normal prothrombin time

d. Pre-treatment for elective surgery require administration of cryoprecipitate to achieve levels of 23–50% of normal

Von Willebrand’s factor is an adhesive protein that mediates platelet adhesion to collagen. In addition, it protects and prevents the rapid removal of factor VIII from blood. The classical deficiency state, Von Willebrand’s disease, is caused by reduction of factor VIII activity (although not as great as Hemophilia A) and the Von Willebrand factor. Clinical manifestations include epistaxis, gingival bleeding, menorrhagia, rare joint or muscle bleeding, and subcutaneous bleeding. Spontaneous bleeding is not as common as in classic Hemophilia A. The syndrome is transmitted as both autosomal dominant (heterozygous) and autosomal recessive disease (homozygous) traits. Therefore there is no sex predilection. Screening laboratory tests include a prolonged aPTT with a normal prothrombin time. In addition, because of the importance of this factor in platelet adhesion, patients display a prolonged bleeding time and have decreased level of factor VIII activity, decreased immunoreactive levels of Von Willebrand’s antigen, and abnormal platelet aggregation responses to ristocetin. The most reliable source of Von Willebrand’s factor is cryoprecipitate.