The effect of heparinized catheter lock solutions on systemic anticoagulation in hemodialysis patients

Background: Hemodialysis catheter thrombosis is associated with loss of catheter patency, catheter-related bacteremia and sepsis. To limit these risks, many renal units use heparin as a catheter-locking solution. In this study we investigate the effect of different concentrations of heparin catheter lock solution on systemic anticoagulation in an investigator-blinded randomized study of patients with non-tunneled (temporary) central venous catheters. Methods: 28 consecutive patients requiring insertion of a temporary non-tunneled dual lumen central venous hemodialysis catheter were randomly allocated to receive either heparin 5,000 IU/ml or heparin 1,000 IU/ml as catheter lock solutions. The primary outcome measure was the difference in activated partial thromboplastin time (APTT) at 10 minutes following catheter locking with heparin 5,000 IU/ml and heparin 1,000 IU/ml. Secondary outcomes included intradialytic blood flow rates, catheter removal due to insufficient hemodialysis blood flow to maintain hemodialysis and catheter-related bacteremia. Results: 13 patients were randomized to the heparin 1,000 IU/ml group with 15 patients randomized to the heparin 5,000 IU/ml group. There was a statistically significant increase in APTT at 10 minutes between groups with median +22.2% (range 0 210) rise in APTT in the heparin 1,000 IU/ml group compared with +373.7% (range 133 - 800) in the heparin 5,000 IU/ml group (p < 0.001). There was no statistically significant difference between groups with the secondary outcomes of intradialytic blood flow, catheter failure rates and catheter-related bacteremia rates. Conclusions: Heparin 1,000 IU/ml catheter lock solution confers a significantly lower risk of systemic heparinization than heparin 5,000 IU/ml without any overtly detrimental effect on intradialytic blood flow, catheter failure rates and catheter-related bacteremia rates.