Tissue plasminogen activator as a hemodialysis catheter locking solution

Tunneled hemodialysis catheters require a "locking solution" between treatments to prevent catheter thrombosis. Heparin locks can be unsafe in patients with life-threatening bleeding diathesis because of unintentional anticoagulation. This study was designed to define the hematologic consequences of using tissue plasminogen activator (t-PA) as an alternative locking solution after heparin-free hemodialysis (HF-HD). Following HF-HD, t-PA 2 mg was instilled into each lumen of the dialysis catheter in 10 patients. Euglobulin clot lysis time (ECLT), fibrinogen, D-dimer, and fibrin degradation products were measured during the last hour of dialysis, and repeated 15 and 30 minutes after catheter locking. Dialysis catheter performance was reassessed at the time of the next hemodialysis. Fibrinogen, D-dimer, and fibrin degradation products were elevated at all time points, but did not change after t-PA. ECLT decreased significantly from baseline 15 minutes after catheter locking (217+/-64 vs. 132+/-75 min, p=0.016). ECLT values had returned to baseline (202+/-56 minutes) by 30 minutes. No episodes of bleeding or catheter thrombosis occurred, and catheter performance did not deteriorate. A 2 mg t-PA locking solution preserved dialysis catheter performance. ECLT decreased at 15 minutes, but normalized by 30 minutes, and did not enter the range in which bleeding would be likely. No clinical events were seen during this transient increase in systemic fibrinolysis.