This study was designed to determine the safety and efficacy of extended, continuous infusion of urokinase plus stent deployment to treat older saphenous vein bypass grafts obstructed by both thrombus and atheromatous material. Thirty patients with angiographic evidence of thrombus and atheromatous material obstructing older vein grafts (mean age 8.3 years) underwent the combined interventions of urokinase infusion and stent deployment. The continuous infusion of urokinase was administered directly into each obstructed vein graft over a mean of 20.5 +/- 8.1 hours (median dose 2.2 +/- 0.7 million units). Stents were deployed at the sites of atheromatous obstruction either before (5 patients) or after (25 patients) infusion of urokinase. Twenty-eight of the 30 patients were successfully treated with the combined interventions (success rate 93.3%). In these 28 patients, percent diameter stenosis at the site of obstruction decreased from 86.0% to -0.2% and Thrombolysis in Myocardial Infarction trial flow increased from 1.0 to 2.5. Two patients (6.7%) developed stent thrombosis followed by myocardial infarction (1 with Q-wave infarction, 3.3%) and congestive heart failure. Minor complications included non-Q-wave myocardial infarction (5 patients, 16.7%) and access-site hemorrhage (5 patients, 16.7%). At 2-week follow-up, anginal symptoms were decreased in all 28 successfully treated patients. At 7.2 +/- 3.7-month follow-up, 5 of the 28 successfully treated patients (17.9%) had reacceleration of angina and angiographically documented restenosis at the site of stent deployment.(ABSTRACT TRUNCATED AT 250 WORDS)