Occlusion of lower extremity vascular bypass grafts results in acute limb-threatening ischemia. The underlying cause of graft failure generally is distal anastomosis stenosis, and relief of culprit stenosis is a required to maintain long-term patency. Of the three thrombolytic agents used for prolonged infusion to accomplish fibrinolysis, streptokinase was the first to be used and is limited owing to the antigenicity that precludes repeated use. Urokinase had been the mainstay of thrombolytic therapy until it was withdrawn by the U.S. Food and Drug Administration in 1999 because of the potential of transmission of infectious agents during its manufacturing process. Recombinant tissue plasminogen activator (rt-PA) has not been studied adequately to assess safety and efficacy, and there are no standardized dosing guidelines. We report our experience with six patients presenting with acute limb-threatening ischemia attributable to thrombosis of synthetic lower extremity bypass grafts. After thrombolysis using rt-PA (mean bolus dose, 12.2 +/- 3.6 mg; range, 6-15 mg administered over 5 minutes followed by infusion at 2 mg/h for 15.6 +/- 6.4 hours; total dose, 51 +/- 16 mg), successful thrombolysis was achieved in 84% of the patients. The primary patency rate was 75% and the secondary patency rate 100% at 16 weeks. One patient underwent amputation owing to unsuccessful thrombolysis. No major bleeding or vascular complications occurred. We conclude that intra-arterial thrombolysis using rt-PA is a safe and effective therapy for patients with thrombotic occlusion of synthetic lower extremity bypass grafts presenting with acute limb-threatening ischemia and allows a high rate of secondary patency, avoiding amputation.
ASJC Scopus subject areas
- Pharmacology (medical)