Chronic and acute consequences of a post-dialysis urokinase lock on permanent hemodialysis catheter function.

BACKGROUND: To treat permanent hemodialysis (HD) catheter dysfunctions due to thrombosis, as an alternative to pre- and intradialytic instillations/infusions of fibrinolytic agents, for practical reasons, a post-dialysis urokinase lock is often preferred. This study aimed to analyze the consequences on catheter function and the cost/effectiveness of an intermittent post-dialysis urokinase lock. METHODS: A prospective open experimental study enrolling 10 dialysis patients with a Tesio twin catheter locked with either heparin 5,000 IU/mL or escalating urokinase doses. Catheter function was monitored measuring the blood flow obtained with an aspiration pressure of -180 mmHg for 28 consecutive HD sessions. RESULTS: No differences were noticed between the blood flow obtained before and after the lock of the catheter with 5000 U/lumen of urokinase (phase 1), but also with 10,000 U/lumen (phase 2) of urokinase. The incidence of catheter dysfunction episodes in the wash-out in the 1st and in the 2nd urokinase phases were, respectively: 13, 6 and 3% (p<0.05 for both 13 vs. 6% and 13 vs. 3%). 47,000 U of urokinase were necessary to avoid one dysfunction episode potentially treatable with an intradialytic urokinase lock of 10,000 U. Between the average blood flow measured in the initial wash out (230 +/- 27 ml/min) and in the 1st (236 +/- 32 ml/min) and also in the 2nd (247 +/- 34 ml/min) urokinase phases significant differences were noticed (p<0.01 and p<0.05, respectively). CONCLUSIONS: The post-dialysis lock with urokinase is associated with an increase in the catheter blood flow and a re-duction in the occurrence of dysfunction episodes. However, the modest impact on dialysis quality and the apparent unfavorable cost/effectiveness of the prophylactic treatment, call for an investigation of its potential advantages in a larger study.