A Comparison of Low Molecular Weight Heparin with Unfractionated Heparin for Anticoagulation during Hemodialysis

Kwon, Tae Hwan; Kim, Yong Lim; Cho, Dong Kyu

Abstract

Hemodialysis requires anticoagulants to prevent fibrin deposition and thrombus formation in the extracorporeal circuit. Unfractionated heparin (UFH) has been used as a conventional anticoagulant for a long time. But recently, many side effects of heparin have been documented: hemorrhage, thrombocytopenia with or without thrombosis, osteoporosis, skin necrosis, alopecia, and hypersensitivity reactions. In the past decade, low molecular weight heparins (LMWH) have been developed. Compared with UFH, these compounds have a longer plasma half life, less variability in the anticoagulant response to fixed doses, and a more favorable antithrombotic to hemorrhagic ratio. Thus, rationales for using LMWH as an alternative to UFH would be a reduced risk of bleeding complications and simplified routines for heparinization due to a longer half-life of the anticoagulant activity. To evaluate the dfficacy and safety of LMWH as an anticoagulant in hemodialysis treatment, we conducted a prospective crossover study with paired comparison of two different heparins in 18 end-stage renal disease patients undergoing hemodialysis. During the first two months of observation, patients received a single bolus of LMWH (Fragmin(R)) 2,552+/-221 aXa IU/one dialysis session. Then patients were switched to UFH dose regimen comprised of a saline prime, no initial bolus and a continuous infusion of 3,174+/-420 IU/one dialysis session for further two months. All hemodialysis sessions were completed uneventfully. The coagulation values of an anti-factor Xa-specific clotting method (Heptest(R)) from citrated whole blood samples taken 15 minutes after starting hemodialysis were 0.47+/-0.21 U/ml with LMWH and 0.12+/-0.03 U/ml with UFH (p<0.05). The values taken 4hours after starting hemodialysis were 0.24+/-0.10 U/ml with LMWH and 0.22+/-0.04 U/ml with UFH (p>). The prolongation of the Heptest clotting times with LMWH and UFH was 2.86 for LMWH and 2.55 for UFH using the shole blood assay. The mean frequency of clot deposition in dialyzer was similar (1.1 vs 0.87) as well as mean venous compression time at the end of dialysis (5.96 vs 6.23 minutes). The hematologic and biochemical parameters such as hemoglobin, platelet count, triglyceride level, total cholesterol and HDL-cholesterol level did not show any differences between the two heparins. We conclude that a single dose of LMWH is effective and safe in repeated use for hemodialysis and prevents clot formation to a similar degree as UFH.