Purpose: Arteriovenous (AV) graft thrombosis is a frequent complication in patients undergoing hemodialysis. Thrombolytic therapy with tissue plasminogen activator (TPA) is hampered by the risk of bleeding complications. Locally delivered plasmin may have similar thrombolytic efficacy with a superior safety profile, so herein it was compared with TPA in a porcine model of AV graft thrombosis.
Materials and methods: AV grafts were created bilaterally between the carotid artery and jugular vein. Graft thrombosis was induced by clamping the grafts for 1 hour. On day 3, one graft was treated with a 2-mL local recombinant plasmin injection (10 mg; n = 10) with the contralateral graft being infused with TPA (10 mg, n = 8) or saline solution (n = 2). Thrombolytic efficacy was assessed by weighing the residual clot and released clot fragments.
Results: After saline solution injection, the mean residual clot weight in the graft was 618 mg. Local administration of TPA showed the least residual clot in the graft (69 mg +/- 26), with large clot particles reaching the venous outflow (241 mg +/- 23). Plasmin treatment significantly reduced the released clot mass versus TPA (52 mg +/- 23; P < .05), whereas residual clot weight was greater compared with TPA treatment (140 mg +/- 22; P < .05). Overall thrombolytic activity of plasmin (ie, residual clot plus released clot) was significantly better than that of TPA (193 mg +/- 25 vs 310 mg +/- 35; P < .05).
Conclusions: The thrombolytic efficacy of recombinant plasmin was shown to be superior to that of TPA in this study.