title: Shear-stress induced acquired von Willebrand syndrome in children with congenital heart disease.
abstract: OBJECTIVE
  To determine the frequency and severity of acquired von Willebrand syndrome (AVWS) in children with stenotic congenital heart disease (CHD) before and after intervention.
  
  
  METHODS
  In this single-centre prospective observational case-control study, 50 children [median age: 26 (range, 0-175) months, bodyweight: 9.5 (2.2-7.5) kg] underwent catheter interventions or cardiac surgery. A total of 26 children with high stenosis [mean gradient: 80 (range, 52-130) mmHg] represented the stenosis group and 24 without relevant stenosis (<20 mmHg) served as the control group. von Willebrand factor (VWF) was analysed with respect to quantity and function before and after corrective or palliative intervention.
  
  
  RESULTS
  Demographic data were comparable. The stenosis group had more surgical and the control group more interventional procedures (P = 0.025). Before intervention, 13 patients from the stenosis group (50%) showed a significant reduction in VWF-multimers compared with no patients in the control group (P <0.001). Collagen binding capacity (VWF:CB) was lower in the stenosis group [0.5 (0.2-2.6) U/ml vs 0.8 (0.4-2.1) U/ml, P <0.05), as was the collagen binding capacity to antigen ratio (VWF:CB/Ag) [0.8 (0.4-1.4) U/ml vs 1 (0.4-1.7) U/ml, P <0.001). After intervention, VWF parameters normalized rapidly within the first 24 h after the procedure and showed no group differences. {VWF:CB [1.7 (0.6-3.7) vs 1.7 (0.6-4.2) U/ml, P = n.s.], VWF:CB/Ag [1.1 (0.5-2.9) vs 1.2 (0.7-2.2), P = n.s} Time in the intensive care unit, respirator time, duration of stay and bleeding before and after intervention were not significantly different.
  
  
  CONCLUSIONS
  AVWS is detected in half of the children with high intra- or extracardiac stenoses and resolves completely after surgical or interventional repair. Even when undergoing surgery on cardiopulmonary bypass, excessive surgical site bleeding was not detected in our study patients.
authors.affiliation: Department of Congenital Heart Disease and Pediatric Cardiology, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany Pediatric Cardiology, Heart Center, University Hospital, Leipzig, Germany loeffelbeinf@web.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Loeffelbein
authors.affiliation: Department of Congenital Heart Disease and Pediatric Cardiology, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany.
authors.forename: Dominika
authors.initials: D
authors.lastname: Funk
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Medical Centre Freiburg, Freiburg, Germany.
authors.forename: Lea
authors.initials: L
authors.lastname: Nakamura
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Medical Centre Freiburg, Freiburg, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Zieger
authors.affiliation: Department of Congenital Heart Disease and Pediatric Cardiology, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Grohmann
authors.affiliation: Department of Cardiovascular Surgery, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Siepe
authors.affiliation: Department of Cardiovascular Surgery, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Kroll
authors.affiliation: Department of Congenital Heart Disease and Pediatric Cardiology, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Stiller
mesh_terms: D000367:Age Factors; D006348:Cardiac Surgical Procedures / Q000009:adverse effects; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005858:Germany; D006330:Heart Defects, Congenital / Q000097:blood / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D006439:Hemodynamics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D019106:Postoperative Hemorrhage / Q000209:etiology / Q000503:physiopathology; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013314:Stress, Mechanical; D013997:Time Factors; D016896:Treatment Outcome; D014842:von Willebrand Diseases / Q000097:blood / Q000209:etiology* / Q000503:physiopathology
keywords: Acquired von Willebrand syndrome; Bleeding; Congenital heart disease; von Willebrand factor multimers