Twenty-nine of 33 patients (88%) with thrombosed lower extremity bypass grafts had angiographic and clinical successful lysis of graft thrombi with rt-PA. Of the successful group, 18 were saphenous vein grafts and 11 PTFE grafts in the femoropopliteal-tibial position. Following lysis, 76% required a secondary procedure (2 PTA, 20 surgical repair and 7 required anticoagulation) to maintain patency.
A matched cohort of patients with bypass grafts who had surgical thrombectomy were compared to the rt-PA successfully treated grafts and analyzed for duration of patency after opening and limb salvage. The Kaplan-Meier curve compared both treatment groups and demonstrated improved graft survival in the rt-PA treated group (p=.01) (median graft survival rt-PA 195 days, surgery 30 days). Limb salvage was marginally significant (p=.064) in favor of the rt-PA treatment group. Single and multi-variant risk factor analysis found smoking and age of the graft adversely affected patency (p=.05 and p=.08 respectively). Graft type, age of the patient, diabetes mellitus, and high blood pressure were not significant factors (p> .15).
Systemic fibrinolysis was identified to varying degrees. Mean decreases in the fibrinolytic constituents include: 59% decrease in clottable fibrinogen, 18% decrease in sulfite fibrinogen, 78% decrease in alpha-2 antiplasmin and varying degrees of increases in DDIMER, B-Beta1-42 and B-Beta15-42 coincident with the constituent changes.
Complications were unrelated to constituent changes. One patient had major bleeding secondary to graft anastomosis disruption.
Thrombolysis with rt-PA is an effective and more durable adjunct treatment option for thrombosed bypass grafts, especially when combined with PTA or surgical repairto maintain patency.
