title: Perioperative onset of acquired von Willebrand syndrome: Comparison between HVAD, HeartMate II and on-pump coronary bypass surgery.
abstract: OBJECTIVE
  Acquired von Willebrand syndrome (AvWS) is associated with postoperative bleeding complications in patients with continuous flow left ventricular assist devices (CF-LVADs). The aim of this study is to analyze the perioperative vWF profile comparing an axial pump (HMII) to a centrifugal pump (HVAD) regarding the correlation between perioperative occurrence of AvWS, early- and late-postoperative bleeding events.
  
  
  METHODS
  From July 2013 until March 2015 blood samples of 33 patients (12 HMII/ 8 HVAD/ 13 controls) were prospectively collected at 12 different time points and analyzed for the vWF antigen (vWF:Ag), its activity (vWF:Ac) and the vWF:Ac/vWF:Ag-ratio (vWF:ratio). The follow up period for postoperative bleeding events was from July 2013 until July 2016.
  
  
  RESULTS
  Postoperatively, there was no difference in the vWF-profile between HVAD and HMII groups. However, a subgroup of patients already had significantly lower vWF:ratios preoperatively. Postoperatively, both CF-LVAD groups presented significantly lower vWF:ratios compared to the control group. Bleeding events per patient-year did not differ between the two groups (HMII vs. HVAD: 0.67 vs. 0.85, p = 0.685). We detected a correlation between vWF:ratio <0.7at LVAD-start (r = -0.583, p = 0.006) or at the end of surgery (r = -0.461, p = 0.035) and the occurrence of pericardial tamponade. In the control group, the drop in both vWF:Ag and vWF:Ac recovered immediately postoperatively above preoperative values.
  
  
  CONCLUSIONS
  A subgroup of patients with end-stage heart failure already suffers AvWS preoperatively. In both CF-LVAD groups, AvWS begins immediately after surgery. Intraoperative vWF:ratios <0.7 correlate with higher incidences of pericardial tamponade and re-operation. The presumably dilutive effect of the heart lung machine on vWF vanishes immediately at the end of surgery, possibly as part of an acute-phase response.
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Feldmann
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital RWTH Aachen, Aachen, Germany.
authors.forename: Rashad
authors.identifier: http://orcid.org/0000-0003-2243-8743
authors.initials: R
authors.lastname: Zayat
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital RWTH Aachen, Aachen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Goetzenich
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital RWTH Aachen, Aachen, Germany.
authors.forename: Ali
authors.initials: A
authors.lastname: Aljalloud
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Woelke
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Judith
authors.initials: J
authors.lastname: Maas
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital RWTH Aachen, Aachen, Germany.
authors.forename: Lachmandath
authors.initials: L
authors.lastname: Tewarie
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitz-Rode
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital RWTH Aachen, Aachen, Germany.
authors.forename: Ruediger
authors.initials: R
authors.lastname: Autschbach
authors.affiliation: Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Steinseifer
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital RWTH Aachen, Aachen, Germany.
authors.forename: Ajay
authors.initials: A
authors.lastname: Moza
mesh_terms: D000368:Aged; D000941:Antigens / Q000097:blood / Q000276:immunology; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000503:physiopathology / Q000601:surgery; D006353:Heart-Assist Devices / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D059035:Perioperative Period / Q000009:adverse effects; D019106:Postoperative Hemorrhage / Q000097:blood* / Q000209:etiology / Q000503:physiopathology; D014842:von Willebrand Diseases / Q000097:blood* / Q000209:etiology / Q000276:immunology / Q000503:physiopathology; D014841:von Willebrand Factor / Q000276:immunology / Q000378:metabolism*
chemical_list: D000941:Antigens; D014841:von Willebrand Factor