RESUMEN
BACKGROUND: The safety and efficacy of low-molecular-weight heparin in the prevention of extracorporeal dialysis circuit clotting among in-center extended duration nocturnal hemodialysis (INHD) patients are unknown. The aim of this study was to determine the safety and efficacy of 2 doses of tinzaparin, among INHD patients receiving 6-8 h hemodialysis, 3 times per week. METHODS: We conducted a retrospective cohort study to examine antifactor Xa levels at time 0, 2 h, 4 h mid-hemodialysis (mid-HD), 6 h, and at end of each INHD session for 4 weeks and to determine extracorporeal dialysis circuit clotting and bleeding events after switching from unfractionated heparin to tinzaparin, using a standard protocol of tinzaparin delivery at the initiation and midpoint of HD. RESULTS: All 16 patients in The Ottawa Hospital INHD program were converted to tinzaparin and followed for 177 INHD sessions. Mean antifactor Xa level at 2 h of HD was 0.41 ± 0.21 (SD) IU/mL, at 4 h (mid-HD) 0.19 ± 0.17 IU/mL, at 6 h 0.44 ± 0.21 IU/mL, and at dialysis end 0.26 ± 0.14 IU/mL. Antifactor Xa levels were undetectable at the start of INHD, suggesting no tinzaparin accumulation. Five patients required an increase in tinzaparin due to extracorporeal dialysis circuit clotting. There were no bleeding events. One patient required a switch to fondaparinux due to an adverse reaction. CONCLUSION: Tinzaparin was safe and efficacious for most INHD patients without accumulation or bleeding. The conversion from unfractionated heparin to tinzaparin required an increased tinzaparin dose for 31% of INHD patients.