Summary
No data about the use of the pentasaccharide fondaparinux, a highly selective indirect
inhibitor of factor Xa,in patients treated with haemodialysis are available. Therefore,
we investigated the pharmacokinetics and -dynamics of fondaparinux in 12 patients
during haemodialysis. The anti-Xa activity (expressed as fondaparinux equivalent)
was monitored, a semiquantitative clotting scale (SQCS) ranging from 0 (no visible
traces of coagula) to 3 (complete clotting of the dialysis circuit) was applied, and
the digital compression time necessary to achieve haemostasis at the puncture site
was determined. After an initial period, when the regular heparin dose was replaced
once weekly by fondaparinux, 0.05 mg/kg, the pentasaccharide was administered for
nine consecutive haemodialysis sessions. Peak anti-Xa activity increased from 0.61
± 0.14 μg/l after the first dose to 0.89 ± 0.24 μg/l after dose 9 (P<0.001), whereas
predialysis anti-Xa activity steadily rose to 0.32 ± 0.09 μg/l (P<0.001). A sufficient
but slightly less effective anticoagulation with a mean SQCS of 1.19 ± 0.71 (n=121)
was obtained by fondaparinux as compared with 0.65 ± 0.58 (n=60, P<0.005) by 4,825
± 1,703 U of unfractionated heparin. Mean digital compression time rose slightly during
fondaparinux from 23.7 ± 7.4 minutes to 24.8 ± 7.5 minutes (P<0.05) and, more important,
six of the 12 patients reported minor bleeding problems during the interdialytic interval.
Thus, fondaparinux can be used to prevent circuit clotting during haemodialysis; however,
accumulation results in an interdialytic increase of anti-Xa activity. Therefore,
fondaparinux should be reserved for patients requiring systemic anticoagulation on
the days off dialysis.
Keywords
Dialysis - anticoagulation - pentasaccharide - fondaparinux - anti-Xa