This study examines the procedural success, complication, and restenosis rates in patients undergoing Palmaz-Schatz stenting of native coronary and saphenous vein graft ostial stenoses. All patients undergoing Palmaz-Schatz stent placement of ostial lesions (> or = 70% diameter stenosis within 3 mm from the arterial ostium) between November 1989 and February 1992 were included in this study. Patients were treated with aspirin dipyridamole, low molecular weight dextran, and heparin during the procedure and received systemic anticoagulation with warfarin for 1 month after the procedure. Angiographic measurements were obtained using electronic calipers. Coronary stents were placed in 41 ostial lesions of 41 patients. The target ostial stenosis was in a saphenous vein graft in 54% and a native coronary artery in 46% of lesions. The mean pre- and postprocedural minimal luminal diameters were 0.8 +/- 0.7 and 3.3 +/- 0.8 mm, respectively (p < 0.0001), corresponding to a mean diameter stenosis of 83.5 +/- 10.0% and 1.0 +/- 4.2%. Two patients had subacute stent thrombosis related to premature discontinuation of antithrombotic medications. Two patients died, 1 because of stent thrombosis and 1 because of progressive renal failure and sepsis. Angiographic follow-up was obtained at a mean of 5.8 +/- 1.8 months in 95% of patients with a successful stent procedure. The overall restenosis rate (> 50% diameter stenosis at follow-up) was 27.8%. Thus, stenting of ostial native coronary and vein graft stenoses can be performed with excellent angiographic and procedural success rates. Restenosis rates appear to be lower than expected using historical control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)