Heparin 1,000 u/mL is what we use for locking almost all our HD patients in Manitoba. We have never switched to 4% citrate as more costly than 1,000 u/mL heparin.
This meta-analysis recommended low dose heparin for HD locks: https://www.ncbi.nlm.nih.gov/pubmed/27191662
This position paper states that heparin 1000 U/ml, or 4% sodium citrate are suitable choices for lock solution in HD: https://www.ncbi.nlm.nih.gov/pubmed/18764795
Lavern Vercaigne did our own (unpublished) study that was presented as a CSN poster years ago with the conclusion that: There were no statistically significant differences in alteplase use or catheter-related infections between the heparin 1,000 u/mL and 4% citrate groups.
Lori Wazny, PharmD.
MB Renal Program