title: Comparison of fondaparinux, low molecular-weight heparin and unfractionated heparin in preventing thrombus formation on mechanical heart valves: results of an in-vitro study.
abstract: OBJECTIVE
  The study aim was to investigate the efficacy of three different anticoagulants in preventing thrombus formation on mechanical heart valves, using an in-vitro system.
  
  
  METHODS
  Blood samples (470 ml) were taken from young and healthy male volunteers and anticoagulated with unfractionated heparin (UFH; n=18), low molecular-weight heparin (LMWH; n=18) or fondaparinux (n=16). Bileaflet mechanical heart valves were placed in a new device--the 'Thrombosis Tester'--and exposed in a continuous circulation at a rate of 80 beats per min to the anticoagulated blood samples for a total exposure time of 60 min. Results for thrombus weight were skewed distributed and presented as log-transformed values.
  
  
  RESULTS
  The weight of each valve was measured before and after 1 h of perfusion; subsequent mean (+/-SD) thrombus weights were 0.739 +/- 0.573 g for UFH, 0.789 +/- 0.099 g for LMWH, and 0.934 +/- 0.145 g for fondaparinux (p = 0.397 for comparison of all groups by ANOVA). Electron microscopy showed concordant results with regard to thrombus formation on heart valve surfaces.
  
  
  CONCLUSIONS
  Fondaparinux and LMWH were as effective as UFH in preventing thrombus formation on mechanical heart valves in vitro. The 'Thrombosis Tester' proved to be a new, unique instrument for investigating the ability of anticoagulants to prevent valve thrombosis on mechanical heart valves under in-vitro conditions.
authors.affiliation: Department of Medicine II, Department of Cardiovascular Surgery, and Transfusion Center, Johannes Gutenberg University, Mainz, Germany. axel.schlitt@medizin.uni-halle.de
authors.forename: Axel
authors.initials: A
authors.lastname: Schlitt
authors.forename: Kathrin
authors.initials: K
authors.lastname: Hamilton
authors.forename: Lars
authors.initials: L
authors.lastname: Maegdefessel
authors.forename: Manfred
authors.initials: M
authors.lastname: Dahm
authors.forename: Cathrin
authors.initials: C
authors.lastname: Theis
authors.forename: Michael
authors.initials: M
authors.lastname: Eichler
authors.forename: Olaf
authors.initials: O
authors.lastname: Brockmann
authors.forename: Ulrich
authors.initials: U
authors.lastname: Steinseifer
authors.forename: Baerbel
authors.initials: B
authors.lastname: Hauroeder
authors.forename: Walter E
authors.initials: WE
authors.lastname: Hitzler
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Rupprecht
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage; D001777:Blood Coagulation / Q000187:drug effects*; D019544:Equipment Failure Analysis; D000077425:Fondaparinux; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006493:Heparin / Q000008:administration & dosage / Q000031:analogs & derivatives*; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D011134:Polysaccharides / Q000008:administration & dosage*; D011475:Prosthesis Failure; D013927:Thrombosis / Q000209:etiology* / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight; D011134:Polysaccharides; C078918:ITF 300; D006493:Heparin; D000077425:Fondaparinux