title: No evidence for increased intraoperative bleeding in aortic-valve stenosis: a comparative analysis of haemotherapy in 136 patients undergoing aortic-valve replacement.
abstract: OBJECTIVE
  An association of aortic-valve stenosis and abnormal bleeding, particularly from gastrointestinal angiodysplasia, has been reported. In this setting, high-shear stress generated by the transvalvular gradient leads to a conformational change of plasmic von Willebrand factor, making this adhesive protein more susceptible for proteolytic cleavage. Consequently, highest-molecular weight multimers of the von Willebrand factor are degraded through a von Willebrand factor specific protease leading to impaired platelet-related haemostasis.
  
  
  RESULTS
  To assess the role of aortic-valve stenosis as a factor predicting abnormal intraoperative bleeding in patients suffering from aortic-valve stenosis, we compared the number of intraoperatively administered blood components during aortic-valve replacement for aortic-valve stenosis (n = 50), aortic-valve insufficiency (n = 19) and combined aortic-valve defects (n = 67). As a result, the three subgroups did not differ significantly regarding the mean number of transfused red-blood cell units (0.94 +/- 1.36, 0.4 +/- 0.9, or 0.86 +/- 1.3, respectively) and plasma units (0.04 +/- 0.28, 0.21 +/- 0.71, or 0.15 +/- 0.61, respectively). None of the patients received platelet concentrates. A multivariate logistic regression model adjusted for age and gender did not show an influence of the presence and severity of aortic-valve stenosis on intraoperatively applied haemotherapy.
  
  
  CONCLUSIONS
  Along with our findings, the presence or severity of aortic-valve stenosis does not predict an increased need for intraoperative transfusion of blood components. Thus, this cardiac defect does not seem to represent a major risk determinant for intraoperative bleeding despite the high prevalence of shear-stress induced von Willebrand factor abnormalities in this setting.
authors.affiliation: LaboMed Coagulation Centre, Berlin, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Sucker
authors.forename: Peter
authors.initials: P
authors.lastname: Feindt
authors.forename: Rainer B
authors.initials: RB
authors.lastname: Zotz
authors.forename: Jens
authors.initials: J
authors.lastname: Litmathe
mesh_terms: D000368:Aged; D001022:Aortic Valve Insufficiency / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000601:surgery*; D016913:Blood Component Transfusion; D005260:Female; D006350:Heart Valve Prosthesis; D006470:Hemorrhage / Q000209:etiology*; D006801:Humans; D007431:Intraoperative Complications; D008297:Male