The recent implantation of intravascular devices (stents), during percutaneous transluminal coronary angioplasty (PTCA), has shown favourable results, decreasing acute occlusion and restenosis during follow-up as compared to PTCA alone. The aim of the study was to assess in a single center the efficacy of the implantation of a Palmaz-Schatz stent in a homogeneous group of patients and to assess the incidence of angiographic restenosis. Fifty-four consecutive patients (mean age 57 +/- 12 years) with single vessel coronary disease at angiography and with objective evidence of myocardial ischemia were studied. According to the duration of angiographic follow-up, patients were divided into two groups: Group I (mean 6 +/- 3 months) and Group II (mean 29 +/- 5 months). Stent implantation was performed electively in 43 patients (80%) while in the remaining 11 (20%) as "bail out" in a failed PTCA. Sixty-five stents were implanted in 54 patients of whom 1 stent in 47 patients (87%), 2 stents in 3 patients (6%) and 3 stents in the remaining 4 patients (7%). The stents were placed in the anterior descending of the left coronary artery in 32 patients (59%), left circumflex coronary artery in 8 patients (15%) and right coronary artery in 14 patients (26%). Mean diameter stenosis before stent implantation was 88 +/- 6% and decreased significantly to 4 +/- 7% after stent implantation (p < 0.0001). No major complications such as death, Q wave myocardial infarction, emergency coronary artery bypass graft or stroke occurred during the procedure. Minor complications such as wrong positioning of the stent, non occlusive acute thrombosis, non Q wave myocardial infarction and transient vessel occlusion occurred in 9% of treated patients. At follow-up, in Group I, 8 patient of 43 (18%) showed a > or = 50% restenosis and 10 patients < 50% restenosis; in the remaining 25 patients no variations in the caliber of the vessel were observed. In Group II, 2 patients of 11 (18%) showed a > or = 50% restenosis and 1 patient < 50% restenosis; in the remaining 8 patients no variations in the caliber of the vessel were observed. Complications during medium and long-term follow-up included total vessel occlusion in 1 patient. In conclusion, these data confirm that the Palmaz-Schatz stent may be implanted with high success and low complication rate. The percentage of restenosis, occurring in near 20% of the cases, remains an unresolved problem, despite the implantation of such intravascular devices.