Effectiveness of low dose urokinase on dialysis catheter thrombolysis.

Thrombosis, a major cause of hemodialysis catheter dysfunction, can be treated with urokinase. We compared protocols using full strength urokinase to the volume of the catheter with low dose therapy. Clotting episodes and successful declottings (blood flow > 200 ml/min) were tracked for 6 months. One hundred four clotting episodes were treated with 5,000 U/ml urokinase to the volume of the catheter lumen for a 1 hr dwell. If unsuccessful, a second dose of 5,000 U/ml was administered and, if needed, a third dose of 125,000 U/lumen. Post treatment, catheters were locked with 5,000 U/ml heparin to the volume of the lumen. Using new protocols, clotting episodes were treated with 2,500 U/lumen urokinase, followed by saline to the volume of the lumen for a 1 hr dwell. A mid dwell injection of 0.2 ml/lumen saline was added to advance the front of active urokinase. If unsuccessful, a second 2,500 U/lumen dose was administered. Heparin lock was 10,000 U/ml heparin to the volume of the lumen. Revised protocols decreased clotting episodes 60% and urokinase charges 81%, while maintaining successful declottings at 74%. Low dose urokinase was as effective as full strength when the active front was advanced mid dwell.