Effect of a Pre Heparin Coated Dialysis Filter on Coagulation During Hemodialysis

• Activation of the intravascular coagulation system during hemodialysis with use of a pre-heparin-coated filter compared to a conventional filter [ Time Frame: Activation of the intravascular coagulation system is assessed during four dialysis sessions within a two weeks period for a single patient ] [ Designated as safety issue: Yes ]
  Blood specimens for analysis of prothrombin fragment 1+2 and beta-thromboglobulin will be drawn at start of hemodialysis and after three and four hours of all hemodialysis sessions.
  
  

• A secondary outcome measure is degree of clot score in the extracorporeal system during hemodialysis with use of a pre-heparin-coated filter compared to the conventional filter. [ Time Frame: The degree of clot score in the extracorporeal system is assessed during four hemodialysis sessions that for a single patient take place within a time frame of two weeks ] [ Designated as safety issue: Yes ]
  Degree of clot score will be evaluated in the venous drip chamber as follows: 1=normal (no signs of clot). 2=fibrinous ring, 3=clot and 4=stop in dialysis due to high degree of clotting
  
  

Device: a pre-heparin-coated hemodialysis filter; Hepran
Use of the pre-heparin-coated filter compared to the conventional filter in a cross over design
Other Names:
• HeprAN membrane
• polyacrylonitrile
• heparin-grafted membrane

In the present study twelve chronic hemodialysis (HD) patients will be included. Exclusion criteria are use of acetylsalicylic acid and/warfarin, clinical signs of infection and disseminated malignant disease. For each patient four HD sessions will be investigated; alternating with use of the pre-heparin-coated filter or the conventional filter. Dalteparin is reduced to 50% of the conventional dose and is given as one single bolus dose at start of HD.

The venous drip chamber will be visually inspected for evaluation of clot score during each HD session. The filter will be visually inspected for clot score at the end of each session.

Blood specimens will be drawn systematically during each HD session to evaluate platelet and coagulation activity as well as anti Factor Xa activity, haematology and urea/creatinine to evaluate dialysis effect.

The antithrombogenic properties of the pre-heparin-coated filter and the conventional filter will be compared by means of statistical tests. The hypothesis is that the pre-heparin-coated filter induces significantly less clot score in the extracorporeal system during hemodialysis and also significantly less intravascular activation of the coagulation system compared to the conventional filter.