Nephrol Dial Transplant (2004) 19: 749
Nephrol Dial Transplant Vol. 19 No. 3 (c) ERA-EDTA 2004; all rights reserved
Prevention of activation of coagulation during haemodialysis and the use of warfarin
Sir,
I read with interest the well written article in the July 2003 issue entitled ‘Different effects of enoxaparin and unfractionated heparin (UFH) on extrinsic blood coagulation during haemodialysis: a prospective study’ by Naumnik et al. [1]. The authors studied 25 haemodialysis (HD) patients using a single dose of enoxaparin. Of these, 12 were randomly assigned to receive UFH as a bolus dose plus continuous infusion, and 13 were maintained on enoxaparin. All patients were followed prospectively for 12 weeks. Among other parameters, a marker of activated coagulation, prothrombin fragment 1+2 (PF1+2) was measured at the start and after 10 and 180 min of HD. They found that PF1+2 was significantly higher than normal pre-dialysis in all patients. In patients on enoxaparin, PF1+2 did not change during HD. In patients switched to UFH, PF1+2 increased significantly pre-dialysis compared with those on enoxaparin. They conclude that enoxaparin ensures efficient anti-thrombotic protection not only during HD but also in between dialysis sessions—as evidenced by stable PF1+2 levels. The authors refer to our study showing that a LMWH, dalteparin, at a single dose of 
5000 IU, provides clinically sufficient anticoagulation, but does not prevent activation of haemostasis during HD [2]. However, they did not refer the important information that this was the case only in patients without warfarin treatment. In warfarin-treated patients, PF1+2 were within normal limits both at the start and during HD.
It is important to know if any of the patients in the study of Naumnik et al. [1] were treated with warfarin since warfarin reduces the blood levels of functional thrombin and therefore also the levels of PF1+2. They stated that criteria for exclusion included application of antiplatelet drugs, but nothing is mentioned regarding warfarin. If some or all of the patients were treated with warfarin, it is not surprising that the levels of PF1+2 did not rise during HD.
Without information concerning warfarin treatment, the conclusion indicated by the authors that enoxaparin ensures a higher anti-thrombotic effect than dalteparin may be disputed.
Conflict of interest statement. None declared.
Department of Internal Medicine Rikshospitalet University Hospital Oslo Norway Email: solbjorg.sagedal{at}rikshospitalet.no
References
- Naumnik, B, Borawski, J, Mysliwiec M. Different effects of enoxaparin and unfractionated heparin on extrinsic blood coagulation during haemodialysis: a prospective study. Nephrol Dial Transplant 2003; 18: 1376–1382
[Abstract/Free Full Text] - Sagedal S, Hartmann A, Sundstrom K, Bjornsen S, Brosstad F. Anticoagulation intensity sufficient for haemodialysis does not prevent activation of coagulation and platelets. Nephrol Dial Transplant 2001; 16: 987–993
[Abstract/Free Full Text]
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