The aim of the study was to determine the safety and efficacy of the second-generation ACS Multi-Link Duet coronary stent system for the treatment of single, symptomatic, de novo, native coronary artery lesions. Between February and June 1998, 427 patients (69.3% male, 51.5% class 3 or 4 angina, 20.1% diabetic, 43.6% hyperlipidemia) were included at 38 centers in this prospective observational study. All patients received ticlopidine 500 mg/day for 1 month and aspirin > or =100 mg/day. The Duet stent was available in 8, 18, and 28 mm length and 3.0, 3.5, and 4.0 mm diameter. After adequate predilatation, stents were successfully implanted, at up to 16 atm, in 99.3% of patients. Mean vessel diameter by core laboratory quantitative coronary angiography was 3.0 +/- 0.53 mm and postprocedural minimum luminal diameter was 2.79 +/- 0.43 mm (12% +/- 9.3% diameter stenosis). At 30 days, 96.7% of patients were event-free and at 6 months 88.1% remained free of major adverse cardiac events. The restenosis rate was 18.1%. The ACS Duet stent was safely implanted in >99% of target lesions by a diverse group of international investigators. With late outcomes at least comparable to the best published results, this stent platform provides safe and effective percutaneous treatment of obstructive coronary artery disease. Cathet Cardiovasc Intervent 2001;54:25-33.