Fibrin sheath removal from central venous catheters: an internal snare manoeuvre.

BACKGROUND Dysfunction of haemodialysis catheters is most commonly due to a narrowing of the catheter lumen and/or formation of a fibrin sheath around the catheter tip. Reported methods for restoring patency of the catheter lumen include passage of a J-tipped guide wire, passage of a biopsy brush through the catheter, or infusion of a thrombolytic agent into the catheter. While these methods are often effective, they suffer from several limitations. We present a minimally invasive technique to remove thrombi and debris from within the lumen of a partially thrombosed haemodialysis catheter while simultaneously stripping the fibrous sheath. METHODS A 0.089 cm nitinol wire is bent to create a loop, which is then inserted via the catheters. Upon exiting the lumen of the catheters, the nitinol wire forces a snare open, which disrupts the fibrin sheath and catches intraluminal thrombi and debris. The technique requires no anaesthesia or recovery time. RESULTS Initial clinical success in our series was achieved in all patients (7/7) as evidenced by restoration of target flow rates on subsequent haemodialysis. None of the patients experienced any complications as a result of the procedure. The catheter 2-, 4-, and 6-week primary success rates were 100% (8/8), 100% (8/8), and 100% (8/8) respectively with a mean duration of 17.1 weeks (range 8-40 weeks). CONCLUSIONS The internal snare technique is an effective, inexpensive and minimally invasive approach to restoring patency to failed central venous access catheters.