To evaluate immediate success and 6-month restenosis rate, 70 Micro Stents II were implanted for 65 stenoses in 63 patients (age 59+/-9 years). Stable angina pectoris was present in 47% of the patients (38% class I to III; 9% class IV), whereas 32% had postinfarction angina and 21% had unstable angina. Indications for stent implantation were elective in 62% and semi-elective in 38% of the patients. Sixty-two percent of the patients received ticlopidin and acetylsalicylic acid for 28 days, whereas 38% of the patients received only acetylsalicylic acid. All stents were deployed successfully at the target site. Subacute closure occurred in 2 patients (3%), both of whom were not treated with ticlopidin. Two other patients (3%) developed non-Q-wave infarction after side branch occlusion during the procedure. The minimum lumen diameter increased from 1.0+/-0.5 mm to 2.8+/-0.4 mm after stent implantation. At follow-up the loss in diameter was 0.9+/-0.6 mm, indicating a net gain of 0.9+/-0.8 mm. Late clinical events (4 weeks to 6 months) were coronary angioplasty of a stented segment (3%), coronary angioplasty of a nonstented segment (10%), and coronary artery bypass grafting (2%). No deaths or myocardial infarction occurred. The procedural success rate was 94% and the event-free survival at 6-month follow-up was 79%. Micro Stent II implantation can be done with a high rate of immediate success and good 6-month outcome. The Micro Stent II has proven to be a versatile device that can also be used in patients with less favorable coronary anatomy or lesion characteristics.