Low dose heparin lock (1000 U/mL) maintains tunnelled hemodialysis catheter patency when compared with high dose heparin (5000 U/mL): a randomised controlled trial

Introduction: Heparin is commonly used after hemodialysis treatments as a locking solution to prevent catheter thrombosis. The comparative efficacy and safety of different heparin concentrations to maintain catheter patency has been previously reported in retrospective studies. We conducted a prospective, randomised, controlled study of 1000 U/mL heparin (low dose) versus 5000 U/mL heparin (high dose) locking solution to maintain patency of tunnelled catheters. Methods: One hundred patients receiving chronic, unit-based hemodialysis with newly placed tunnelled hemodialysis catheters (less than 1 week) were randomly assigned to either a low dose (n = 48) or high dose heparin (n=52). The primary intention-to-treat analysis examined time to malfunction in both groups over a 90 day period. A secondary analysis compared baseline patient characteristics in relation to catheter malfunction. Findings: Overall rate of catheter patency loss was 32% of catheters by 90 days. There was no significant difference in time to malfunction of catheters locked with low dose or high dose heparin (P = 0.5770). Time to catheter malfunction was not associated with diabetic, hypertensive or smoking status. There was no difference in mean delivered blood flow rate, venous and arterial pressure, and dialysis adequacy between low dose and high dose groups. No patient suffered a hemorrhagic complication requiring hospitalisation during the study period. Discussion: Low dose heparin is adequate to maintain tunnelled hemodialysis catheter patency when compared with high dose heparin. The study also suggests that there is no relationship between catheter malfunction and diabetic, hypertensive or smoking status.