title: Acquired von Willebrand syndrome and mitral valve prosthesis leakage. A pilot study.
abstract: BACKGROUND
  Of patients with severe aortic stenosis, 15-25% present with bleeding episodes possibly attributable to acquired von Willebrand syndrome (AVWS). AVWS associated with mitral valve prosthesis leakage has not been reported.
  
  
  RESULTS
  Five patients receiving appropriate oral anticoagulation showed mitral valve prosthesis leakage and bleeding episodes; all of them required hospitalization and two blood transfusions, and a von Willebrand factor (VWF) analysis was performed. Two patients with normal functioning metallic prosthesis valves were included as controls. Before surgery, after cessation of acenocumarol, the patients had prolonged activated partial thromboplastin time; four had prolonged closure time (CT) from the platelet function analyzer. Factor VIII procoagulant activity (FVIII:C), VWF ristocetin cofactor activity (VWF:RCo), and VWF collagen binding (VWF:CB) were considerably elevated, while VWF antigen (VWF:Ag) was most elevated. Disproportionate VWF:RCo/VWF:Ag and VWF:CB/VWF:Ag ratios were seen with the loss of large VWF multimers. Following surgery, all parameters were markedly increased and the ratios, CT, and multimeric VWF profile became normal.
  
  
  CONCLUSIONS
  Acquired VWF qualitative alterations in mitral valve prosthesis leakage may be associated with or contribute to bleeding diathesis. AVWS should be taken into consideration in patients with mitral valve prosthesis leakage with bleeding diathesis not explained by excessive oral anticoagulation.
authors.affiliation: Servicio de Hematología y Hemoterapia, INIBIC-Complexo Hospitalario Universitario A Coruña, Carretera del Pasaje s/n, A Coruña, Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: Pérez-Rodríguez
authors.forename: Joana Costa
authors.initials: JC
authors.lastname: Pinto
authors.forename: Esther
authors.initials: E
authors.lastname: Lourés
authors.forename: Angela
authors.initials: A
authors.lastname: Rodríguez-Trillo
authors.forename: José J
authors.initials: JJ
authors.lastname: Cuenca
authors.forename: Javier
authors.initials: J
authors.lastname: Batlle
authors.forename: María F
authors.initials: MF
authors.lastname: López-Fernández
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage; D016022:Case-Control Studies; D005260:Female; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008943:Mitral Valve / Q000601:surgery*; D010865:Pilot Projects; D014842:von Willebrand Diseases / Q000503:physiopathology*
chemical_list: D000925:Anticoagulants