Silastic cuffed catheters are assuming a greater role in providing long-term vascular access for hemodialysis patients. However, catheter thrombosis, fibrin sheath formation, and catheter malposition are recurrent problems that reduce extracorporeal flow rates and shorten catheter life. We reviewed 163 consecutive episodes of catheter malfunction that occurred in 121 catheters in 88 patients over a 3.5-year period. Intraluminal instillation of urokinase was successful in reestablishing an extracorporeal flow rate of > or = 300 mL/min in 74% of episodes. The 42 remaining episodes (26%) were radiologically evaluated. Two catheters required replacement for catheter kinking or insufficient catheter length. Two additional catheters were malpositioned; both were successfully repositioned with percutaneous techniques. A fibrin sheath was detected encasing the catheter in 38 instances. The fibrin sheath was successfully stripped from the distal portion of the catheter in 36 of the 38 instances. Using endoluminal thrombolytic therapy and percutaneous mechanical techniques, we have extended the mean survival for catheters intended for permanent vascular access to 12.7 months and have allowed 95% of the catheters inserted for temporary use to reach their use goal. Tunnel tract infection and catheter-mediated bacteremia were the primary reasons for catheter removal.