title: Pediatric Acquired von Willebrand Syndrome in Cardiopulmonary Disorders: Do Laboratory Abnormalities Predict Bleeding Risk?
abstract: There are conflicting reports on whether or not laboratory abnormalities in pediatric acquired von Willebrand syndrome (AVWS) predict bleeding manifestations in patients with cardiopulmonary disorders (CPD). We retrospectively reviewed charts of patients with AVWS and CPD (n=16) seen at Texas Children's Hospital from 2003 to 2012. The most common CPD were valve stenoses, ventricular septal defects, and pulmonary hypertension. All patients had loss of high molecular weight multimers. Fifteen (94%) patients presented with bleeding symptoms, with menorrhagia and epistaxis being the most common. Von Willebrand ristocetin cofactor activity (VWF:RCo), as well as the use of anticoagulant or antiplatelet medication, did not predict bleeding manifestations (P=0.70 and 0.84, respectively). VWF:RCo/VWF antigen (Ag) ratio of <0.7 was significantly associated with presence of bleeding symptoms. All patients who had complete repair of their cardiac defect experienced normalization of VWF multimers and VWF:RCo/Ag ratio, as well as bleeding symptom resolution. We conclude that increased bleeding risk is associated with low VWF:RCo/Ag ratio in pediatric AVWS due to CPD. However, other laboratory abnormalities such as VWF:RCo level and qualitative multimer analysis, do not appear to predict bleeding. Future studies exploring quantification of multimer loss may be helpful in further assessing bleeding risk associations.
authors.affiliation: Departments of Pediatrics/Hematology Section, Transfusion Medicine & Coagulation, Baylor College of Medicine and Texas Children's Hospital, Houston, TX.
authors.forename: Saman K
authors.initials: SK
authors.lastname: Hashmi
authors.forename: Mireya P
authors.initials: MP
authors.lastname: Velasquez
authors.forename: Donald L
authors.initials: DL
authors.lastname: Yee
authors.forename: Shiu-Ki
authors.initials: SK
authors.lastname: Hui
authors.forename: Donald
authors.initials: D
authors.lastname: Mahoney
authors.forename: Lakshmi V
authors.initials: LV
authors.lastname: Srivaths
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006330:Heart Defects, Congenital / Q000097:blood / Q000150:complications* / Q000601:surgery; D018056:Hemorheology; D006470:Hemorrhage / Q000209:etiology; D006474:Hemorrhagic Disorders / Q000097:blood* / Q000209:etiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood / Q000150:complications*; D007223:Infant; D008297:Male; D055503:Protein Multimerization; D012189:Retrospective Studies; D018570:Risk Assessment; D033081:Shear Strength; D055815:Young Adult; D014842:von Willebrand Diseases / Q000097:blood* / Q000209:etiology; D014841:von Willebrand Factor / Q000737:chemistry
chemical_list: D014841:von Willebrand Factor