Comparison of
Fondaparinux, Low Molecular-Weight Heparin and Unfractionated Heparin
in Preventing Thrombus Formation on Mechanical Heart Valves: Results
of an In-Vitro Study
Axel Schlitt1, Kathrin Hamilton2, Lars Maegdefessel1, Manfred Dahm1,
Cathrin Theis1, Michael Eichler2, Olaf Brockmann2, Ulrich Steinseifer2,
Baerbel Hauroeder3, Walter E. Hitzler1, Hans J. Rupprecht1
1Departments of Medicine II, Department of
Cardiovascular Surgery, and Transfusion Center, Johannes Gutenberg-University,
Mainz, 2Applied Medical Engineering, Helmholtz-Institute of the RWTH-Aachen,
Cardiovascular Engineering, Aachen, 3Bundeswehrzentralinstitut der
Bundeswehr, Koblenz, Germany |
Background and aim of the study: 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.
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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.
Conclusion: 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.
The Journal of Heart Valve Disease 2006;15:809-814 |