Efficacy and safety of low-dose heparin in hemodialysis.

Introduction: The dose of unfractionated heparin (UFH) administered during hemodialysis (HD) varies widely. This prospective study evaluated the safety and efficacy of UFH dose de-escalation.

Methods: Sixty-six prevalent patients on HD receiving UFH per standard-dose protocol (load dose [LD] 50-75 units/kg, maintenance dose [MD] 500-1000 units/hour) had heparin prescription converted to low-dose protocol (start LD 15 units/kg and MD 500 units/hour; dose adjusted in small increments based on assessments of extracorporeal blood circuit). Coagulation parameters, dialysis adequacy, dialyzer clotting, anemia management, and dialyzer reuse rates were compared based on the heparin protocol.

Findings: Mean(SD) UFH dose per HD session, before and after protocol conversion, was 6178(2644) and 2913(1116) units, respectively (P < 0.0001). This corresponded to LD 52.1(16.6) units/kg and MD 615(207) units/hour with standard-dose protocol, and LD 18.3(6.5) units/kg and MD 505(27) units/hour with low-dose protocol (P < 0.0001). Mid and postdialysis aPTT was 55.3(31.2) and 35.1(7.8) seconds before, and 37.3(12.9) and 31.5(5.3) seconds after conversion (P = 0.007 and 0.003, respectively); no significant changes in D-dimer levels occurred. Low-dose UFH was associated with a small increase in URR and spKt/V (73.0 and 1.54) compared with dialysis clearance on standard-dose UFH (71.2 and 1.48, respectively, P = 0.02). Weekly dose of ESA decreased by 2388 units postconversion (P = 0.03), while hemoglobin levels and the weekly dose of intravenous iron did not change (P = 0.16 and 0.78). A small rise in the rate of moderate dialyzer clotting at the end of HD was noted with low-dose UFH (5.7% vs. 7.5%, P = 0.002); the rate of severe dialyzer clotting events did not change (P = 0.91). No change in the dialyzer reuse rate was noted (18.5 vs. 17.0 treatments, P = 0.26).

Discussion: Low-dose heparinization did not compromise dialysis adequacy and permitted ESA dose reduction. Our findings suggest that in prevalent patients on HD, UFH dose of 15-20 units/kg loading and 500 units/hour maintenance was medically safe and effective.