Using urokinase to restore patency of tunnelled catheters in patients with end stage renal disease on haemodialysis

M Bywater, M Kumwenda

Glan Clwyd Hospital, Wales

Background: The “Gold Standard” vascular access is the arterio-venous fistula in patients with End Stage Renal Disease (ESRD) on haemodialysis. The increase in patients with poor vasculature and failed fistulae e.g.the elderly and people with diabetes accepted for haemodialysis has led to an increase in the proportion of patients dependent on tunnelled catheters. Up to 50% of tunnelled catheters are removed due to suboptimal blood flow. Several options to restore catheter patency are adopted before catheter removal: 1) Forceful and rapid infusion of 0.9% saline 2) Endoluminal Brushing 3) Use of fibrinolytic agents e.g. urokinase or alteplase. In our dialysis centre we used option 1 followed by urokinase in tunnelled catheters with poor blood flow.

Objectives: We report preliminary results of our prospective experience using urokinase as a fibrinolytic agent for tunnelled haemodialysis catheters with suboptimal blood flow for adequate dialysis.

Method: Patients with ESRD dialysing via tunnelled catheters with blood flow persistently below 200ml/min were identified between 2002 and 2004. 5000u of urokinase was injected into each catheter lumen, left in situ and aspirated after 60 minutes. Haemodialysis was recommenced, however, if the blood flow remained below 200ml/min a second dose of urokinase catheter lock was done and further dialysis attempted the next day. If the blood flow was still <200ml/min urokinase was infused at 125000u per catheter lumen over 3 hours and dialysis was resumed soon afterwards. If the blood flow was persistently <200ml/min, urokinase infusion was repeated once more. The catheter was removed and replaced with a new one via guidewire exchange 24 hours after the second infusion if blood flow of >200ml/min was not achieved.

Results: Patients- 8 males,12 females, mean age 61.2 yrs, patency was restored in 11 (55%) catheters using urokinase lock, 6(30%) using urokinase infusion Thrombolysis was unsuccessful in 3 (15%) catheters which were removed and new ones inserted. None of these patients had developed hyperkalaemia nor pulmonary oedema at the time for dialysis not to be postponed following the first urokinase lock.

Conclusion: Thrombolysis with urokinase restored patency of the majority of tunnelled haemodialysis catheters with poor/suboptimal blood flow in patients with ESRD. The use of urokinase was safe and prevented premature loss of valuable access. There is a need for a larger study in the UK to determine the efficacy of urokinase as a thrombolytic agent in tunnelled haemodialysis catheters with poor blood flow.