The purpose of this study was to evaluate the feasibility, safety, and efficacy of bailout coronary stenting without anticoagulation or intravascular ultrasound guidance in patients with acute or unequivocal threatened closure after conventional angioplasty. One hundred twenty consecutive patients were prospectively enrolled according to the following criteria: 1) acute or threatened closure after balloon angioplasty; 2) reference vessel diameter > or = 2.5 mm. All patients after stent implantation were on antiplatelet treatment with aspirin and ticlopidine. Four types of stents were used: Palmaz-Schatz (J&J), Gianturco-Roubin (Cook), Freedom (Global Therapeutics), and Microstent (AVE). Procedural results: a total of 206 stents were implanted in 134 target lesions with a stent deployment success rate of 100%; 44 target lesions were treated with multiple stent implantation; the mean luminal diameter after stenting was 3.14 +/- 0.34 mm, and the mean final percent diameter stenosis was -2 +/- 10%; the mean balloon to vessel ratio was 1.11 +/- 0.15; the mean final pressure inflation was 13.9 +/- 2.4 atm; an optimal angiographic result was achieved in 128 lesions (96%). In-hospital results: in-hospital recurrent ischemia occurred in 4 patients (3%); recurrent ischemia resulted directly in death in 1 patient, in nonfatal Q-waves infarction in 2 patients, and in emergency coronary artery surgery in 1 patient. Six-month clinical follow-up results: event free survival rate was 77%; 1 patient had non fatal infarction; the incidence of repeat revascularization procedures was 19%; there were no cardiac deaths. Angiographic follow-up results (follow-up rate 93%): the restenosis or reocclusion rate was 28%. Bailout coronary stenting without chronic anticoagulation treatment or intravascular ultrasound guidance may be considered a highly feasible and safe treatment for acute or threatened closure after failed angioplasty.