Catheter lock heparin concentration: effects on tissue plasminogen activator use in tunneled cuffed catheters.

The optimal cost-effective heparin concentration for locking tunneled cuffed hemodialysis catheters (TCC) is unclear. We performed a retrospective review of tissue plasminogen activator (tpa) use in TCC in 2 hemodialysis units that used different heparin concentrations for TCC lock to evaluate the effectiveness of lower dose heparin as a lock for TCC. Catheter blood flow rate per treatment, units of heparin given during treatments, patient hemoglobin values and use of warfarin, and tpa use were compared for all patients using TCC for at least 3 months in 2 in-center hemodialysis units between 11/04 and 5/05. Both units used the same type of catheters and biocompatible, non-re-use dialyzers. Unit A used heparin 1000 U/mL for catheter locks, and Unit B used heparin 10,000 U/mL for catheter locks. Twelve of 19 Unit A patients, tpa and 14 of 45 Unit B patients received intracatheter during the study period (p=0.0009). There were no differences in the number of patients on warfarin, treatment blood flow rate, or mean hemoglobin levels between the 2 groups. The mean heparin units given during hemodialysis treatments was higher in Unit A patients (3.92+/-2.2 vs. 3.83+/-2.5 1000 U, p=0.05). Assuming a 4.1 mL total catheter lumen volume, the cost of heparin 1000 U/mL lock was 0.20 dollars per treatment and heparin 10,000 U/mL cost 2.67 dollars/treatment; tpa cost 89.02 dollars/use. Using the 10,000 U/mL heparin as a catheter lock was associated with less frequent use of tpa. However, the significantly lower cost of the 1000 U/mL heparin could result in significant savings despite higher tpa use. This retrospective, uncontrolled study of a small number of patients suggests that comparing low and high heparin concentrations as a TCC lock would be worthwhile. Prospective studies would be helpful to define the most appropriate and cost-effective lock for TCC.