title: Acquired von Willebrand syndrome in patients with extracorporeal life support (ECLS).
abstract: OBJECTIVE
  Extracorporeal life support (ECLS) is used for patients with refractory heart failure with or without respiratory failure. This temporary support is provided by blood pumps which are connected to large vessels. Bleeding episodes are a typical complication in patients with ECLS. Recently, several studies illustrated that acquired von Willebrand syndrome (AVWS) can contribute to bleeding tendencies in patients with long-term ventricular assist devices (VAD). AVWS is characterized by loss of the high molecular weight (HMW) multimers of von Willebrand factor (VWF) as a result of high shear stress and leads to impaired binding of VWF to platelets and to subendothelial matrix. Since ECLS and VAD share several features, we investigated patients with ECLS for AVWS.
  
  
  METHODS
  We analyzed 32 patients with ECLS and 19 of them without support. To diagnose AVWS, ratios of ristocetin cofactor activity (VWF:RCo) and collagen binding capacity (VWF:CB) to VWF antigen (VWF:Ag) were employed in conjunction with multimeric analysis.
  
  
  RESULTS
  Reduced VWF:RCo/VWF:Ag ratios were identified in 28 ECLS patients. Furthermore, VWF:CB/VWF:Ag ratios were decreased in 31 patients. HMW multimers of VWF were missing in the same 31 patients. Thus, 31 of 32 ECLS patients presented with AVWS. Twenty-two of the 32 patients suffered from bleeding complications. Without support, AVWS was not detectable in any analyzed patient.
  
  
  CONCLUSIONS
  Our data indicate that AVWS is a typical disorder in patients with ECLS. We hypothesize that AVWS could contribute to aggravation of bleeding tendencies in ECLS patients.
authors.affiliation: Department of Cardiovascular Surgery, University Heart Center Freiburg-Bad Krozingen, Hugstetter Str. 55, 79106 Freiburg, Germany. claudia.heilmann@uniklinik-freiburg.de
authors.forename: Claudia
authors.initials: C
authors.lastname: Heilmann
authors.forename: Ulrich
authors.initials: U
authors.lastname: Geisen
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Beyersdorf
authors.forename: Lea
authors.initials: L
authors.lastname: Nakamura
authors.forename: Christoph
authors.initials: C
authors.lastname: Benk
authors.forename: Georg
authors.initials: G
authors.lastname: Trummer
authors.forename: Michael
authors.initials: M
authors.lastname: Berchtold-Herz
authors.forename: Christian
authors.initials: C
authors.lastname: Schlensak
authors.forename: Barbara
authors.initials: B
authors.lastname: Zieger
mesh_terms: D000328:Adult; D000368:Aged; D015199:Extracorporeal Membrane Oxygenation; D005858:Germany; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D013577:Syndrome; D055815:Young Adult; D014842:von Willebrand Diseases / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology