Background: To examine the long-term outcome of coronary angioplasty, lesions that remained patent after 3 to 12 months were monitored angiographically at 3-year intervals. There were 252 lesions successfully dilated (from 83% ± 13% preprocedural stenosis to 19% ± 14% residual stenosis) between 1983 and 1986 that remained patent on follow-up angiography (23% ± 15% stenosis) and were monitored further at our outpatient department. Methods and Results: Repeat angiography was done for 186 lesions at 2 to 4 years and showed that 179 were patent (0% to 50% stenosis), one had mild stenosis (55% to 70% stenosis), and six had severe stenosis (75% to 100% stenosis). Angiography was repeated for 138 lesions at 5 to 7 years, showing that 127 were patent, four had mild stenosis, and seven had severe stenosis. Finally, angiography was performed for 78 lesions at 8 to 10 years, showing that 63 were patent, four had mild stenosis, and 11 had severe stenosis. Conclusions: Although numerous lesions were lost to follow-up, most appeared to remain patent for 4 years, after which a significant number developed restenosis. (Am Heart J 1998;135:1076-80.)