Thrombolysis for restoration of patency to haemodialysis central venous catheters: A systematic review

Urokinase, previously used to restore patency to thrombosed haemodialysis c atheters, is now unavailable in North America. We performed systematic reviews of four questions related to the safety and efficacy of alternative agents for catheter thrombolysis, searching Medlin e and the Cochrane Controlled Clinical Trials Register. In dialysis patients, large case series have documented that urokinase is s afe and effective (> 70 % efficacy for catheter instillation, and > 80 % fo r systemic lysis). Experience with streptokinase is limited and allergic co mplications develop with repeated use. Studies of catheter instillation wit h 1-2 mg of tPA per lumen reported short-term success in 83-98 % of uses. O ne non-peer-reviewed study described 44-59 % success using systemic tissue plasminogen activator (tPA), 2.5 mg through each of 2 lumens, over 1 h. Met a-analysis of randomized comparisons of urokinase and tPA as full-dose thro mbolytic agents suggested that 1 mg tPA was likely equivalent in thrombolyt ic potency to 36,000 units urokinase. In nondialysis populations, four case series suggested that catheter instillation with 0.5-2 ]mg tPA was effecti ve and safe in reestablishing patency, and a randomized controlled trial fo und 2-4 mg tPA more effective than 5,000-10,000 units urokinase. No complic ations have been reported in any patient treated with systemic or local tPA for catheter thrombolysis. In studies of fistula thrombolysis with 5-50 mg tPA major complications occurred in one episode in 130 patients treated. This review suggests that 1-2 mg/lumen tPA is a suitable dose for catheter instillation and likely to be more effective than 5000 units/lumen urokinas e. Systemic lysis with 5-10 mg tPA is likely to be safe and effective in su itably selected patients. Further studies are needed.