The use of PEG-Hirudin in chronic hemodialysis monitored by the Ecarin Clotting Time: influence on clotting of the extracorporeal system and hemostatic parameters.

Aim: The aim of our study was to investigate the use of polyethylene glycol (PEG)-Hirudin (PEG-H) as an anticoagulant in hemodialysis including drug monitoring with the Ecarin Clotting Time (ECT) in whole blood and to compare this regimen with standard anticoagulant unfractionated heparin (UFH) for influence on hemostatic parameters and clot frequency of the extracorporeal system.

Patients And Methods: The application of PEG-H as an anticoagulant in patients on chronic HD was studied in 20 patients (12 males, 8 females) from a single center in an exploratory, open-label, controlled, single-blind, dose-finding study. The patients were divided in 2 groups with 10 patients each (Group I and II); both received 3 dialyses with UFH, thereafter Group I received 5 dialyses with PEG-H and Group II 10 dialyses with PEG-H. Starting dose of PEG-H in the first dialysis was a bolus of 0.08 mg/kg bwt, the mean dose of the following HD was 0.041 mg/kg bwt (range 0.026 0.065 mg/kg bwt). PEG-H was applied as an intravenous bolus-dose followed by a 0.9% saline as a placebo-infusion. HD was performed regularly 3 times a week. All dialysis treatments were performed exclusively with a hollow fiber dialyzer type. Fibrinogen, antithrombin III, prothrombin fragments, thrombin-antithrombin and soluble fibrin were measured with commercial tests. ECT was determined in a mechanical coagulometer. A semiquantitative score was given for the presence of clots in the extracorporeal system after each dialysis.

Results: PEG-H was effectively used as an anticoagulant in 150 chronic dialysis treatments using ECT as a simple monitoring method. The optimal whole blood concentration for PEG-H is 600-1000 ng/ml. Clotting in the whole extracorporeal system was decreased by 45% (p = 0.059) with PEG-H anticoagulated HD in comparison to UFH. Fibrinogen, prothrombin fragments (F1+2-fragments) and thrombin-antithrombin-complex showed no significant change in comparison with UFH, antithrombin III (AT III) increased to normal concentrations. Highly sensitive coagulation markers such as a soluble fibrin showed a significant decrease (p < 0.001) before and after HD with PEG-H compared with UFH.

Conclusion: PEG-H can be used effectively as an alternative anticoagulant in patients on chronic HD using ECT as a simple drug monitoring method. The lower frequency of clots in the extracorporeal system, the stronger and more efficient inhibition of coagulation during HD as indicated by soluble fibrin, may have a positive influence on the disturbed blood coagulation of these patients.