The results of Palmaz-Schatz stent implantation in failed angioplasty in 60 consecutive patients were compared with those of elective stent implantation in 100 consecutive patients. Stent implantation was successful in all of the failed group and in 99% of the elective. Stent thrombosis occurred in 16.7% of the failed group and 2% of the elective (p = 0.001). In the failed angioplasty group, stent thrombosis was associated with a greater frequency of preprocedure complex morphology (40% vs 12% in the nonthrombosis group, p = 0.05), persistent uncovered dissection after stenting (60% vs 14%, p = 0.004), and greater residual stenosis (39.9% +/- 25.3% vs 24.9% +/- 13.08%, p = 0.008) after stenting. Vessel patency was reestablished by angioplasty in 5 of 10 with stent thrombosis. Of these 5 patients, however, 2 suffered repeat stent thrombosis; 1 died suddenly four months later; and restenosis occurred in the remaining 2. Follow-up angiography was performed in 98% of the elective group at 6.3 +/- 2.6 months and 96% of the failed angioplasty group at 6.4 +/- 2.1 months. Restenosis (> or = 50% stenosis) occurred in 32% of the elective group and 50% of the failed angioplasty group (p = 0.041). Multiple logistic regression analysis identified multiple stent implantation (F = 6.75, p = 0.01) and triple-vessel disease (F = 3.46, p = 0.06) as independent positive predictors of restenosis. In conclusion, stent implantation in cases of failed angioplasty could be performed with a success similar to that of elective stent implantation but was associated with a greater frequency of stent thrombosis and restenosis.