Use of Tinzaparin for Anticoagulation in Hemodialysis

Inclusion Criteria: * Age \>= 18 years * End stage renal disease maintained on outpatient hemodialysis for \>= 3 months * Frequency of hemodialysis: 3 times per week * Anticoagulation with an unfractionated heparin protocol for at least 4 weeks * Patient or legal guardian able to provide written consent * Baseline INR \<= 1.3 * Baseline platelet count \>= 80,000 x 10\^9/L Exclusion Criteria: * Therapeutic systemic anticoagulation * Clinically apparent bleeding in the last 2 months * High risk of bleeding * Planned major surgery in the next 4 months * Major surgery in the past 48 hours * Pregnant or lactating * Child bearing potential * Allergy/intolerance to heparin or history of heparin induced thrombocytopenia * Current participation in a related randomized drug trial