title: Platelet dysfunction and acquired von Willebrand syndrome in patients with left ventricular assist devices.
abstract: OBJECTIVE
  Unexplained bleeding events are a severe complication in patients with left ventricular assist devices (LVADs). Platelet dysfunction and acquired von Willebrand syndrome (AVWS) may contribute to bleeding tendencies. Yet, comprehensive data with respect to platelet function and AVWS in LVAD patients in terms of bleeding events are scarce.
  
  
  METHODS
  Thirty-nine HeartMate II patients were included in this study. Data of at least two time points were available for each patient. Platelet function was analysed via light transmission aggregometry in 19 patients without LVAD, 28 in early (≤14 days) and 30 in late postimplantation states (≥30 days). Von Willebrand factor (VWF) antigen, VWF collagen binding capacity and VWF multimeric analyses were performed in 26 patients without LVAD, 39 in early and 33 in late postimplantation states to diagnose AVWS. Bleeding complications were recorded for 39 patients in the early and 33 in the late postoperative period.
  
  
  RESULTS
  Platelet dysfunction was detectable in 18 of 19 without LVAD and in all patients following LVAD implantation. Platelet aggregation values did not change over time (without-early, P = 0.27, n = 14; early-late, P = 0.17, n = 21). AVWS was not diagnosed in patients without LVAD, except for one. On LVAD, 33 of 39 patients had AVWS in the early and all in the late period (n = 33). Bleeding events occurred in 44% of patients in the early and in 64% of patients in the late period.
  
  
  CONCLUSIONS
  According to our data, platelet aggregation is often impaired in LVAD patients even without an implanted LVAD. Additionally, appearance of AVWS seems to be closely linked to LVAD implantation.
authors.affiliation: Department of Cardiovascular Surgery, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany.
authors.forename: Maral
authors.initials: M
authors.lastname: Baghai
authors.affiliation: Department of Cardiovascular Surgery, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany claudia.heilmann@uniklinik-freiburg.de.
authors.forename: Claudia
authors.initials: C
authors.lastname: Heilmann
authors.affiliation: Department of Cardiovascular Surgery, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany.
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Beyersdorf
authors.affiliation: Laboratory for Hemostaseology, Department of Pediatrics and Adolescent Medicine, University Freiburg Medical Center, Freiburg, Germany.
authors.forename: Lea
authors.initials: L
authors.lastname: Nakamura
authors.affiliation: Institute for Clinical Chemistry and Laboratory Medicine, University Freiburg Medical Center, Freiburg, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Geisen
authors.affiliation: Department of Medical Biometry and Statistics, University Freiburg Medical Center, Freiburg, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Olschewski
authors.affiliation: Laboratory for Hemostaseology, Department of Pediatrics and Adolescent Medicine, University Freiburg Medical Center, Freiburg, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Zieger
mesh_terms: D000328:Adult; D000368:Aged; D001791:Blood Platelet Disorders / Q000209:etiology*; D006353:Heart-Assist Devices / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged; D010976:Platelet Count; D055815:Young Adult; D014842:von Willebrand Diseases / Q000209:etiology*
keywords: Acquired von Willebrand syndrome; Bleeding; Circulatory assist devices; Platelets