BACKGROUND: Transluminal balloon coronary angioplasty is one of the most widely used therapeutic procedures in the treatment of patients with coronary artery disease. However, restenosis remains a major limitation of percutaneous coronary angioplasty despite extensive efforts to prevent recurrence. We examined the immediate and long-term results of 516 patients (617 lesions) who underwent coronary angioplasty to evaluate the initial success rate, complications, restenosis rate, and the factors affecting initial success and restenosis. METHODS: The coronary angioplasty of 516 patients(M/F : 388/128, mean age : 57 years), 671 lesions was done with conventional technique and follow-up coronary angiogram was obtained 4 to 6 months after angioplasty in 168 patients. The angiographic restenosis was defined as >50% luminal narrowing in a previously dilated lesion, and the clinical restenosis defined as the recurrence of typical angina and/or positive tests of treadmill test, or thallium scintigraphy during follow-up period. RESULTS: 1) The coronary angioplasty was successful in 459 of 516 patients(89%), 604 of 671 lesions(90%). The success rate was significantly lower in subgroups with type C lesion(52.2%, p<0.001), right coronary artery (83.7%, p<0.05) and <3.0mm of size of lesion(81.4%, p<0.001). 2) The procedural complications were as follows : intimal dissection in 143 lesions(21.3%) including acute closure in 9 lesions(1.3%), emergency bypass surgery in 6 patients(1.2%), myocardial infarction in 9 patients(1.7%), rupture of coronary artery in 2 patients, air embolism in 1 patient, and death in 1 patient(0.19%). 3) The causes of the procedural failure(n=57 patients) included guidewire passage failure in 27, balloon passage failure in 4, catheter engagement failure in 1, acute closure in 7, coronary artery rupture in 2, and suboptimal result in 16 patients. 4) Clinical follow-up was obtained in 455 patients for a mean follow-up duration of 13.2months and clinical restenosis rate was 31%(141/455). The repeat coronary angiogram was performed in 168 patients(209 lesions) for a mean follow up duration 5.4month and demonstrated 48%(100/209) angiographically restenosis rate. The clinical restenosis rate was significantly lower in subgroups with <10% of residual stenosis(18.9%, p<0.05), left circumflex coronary artery(18.5%, p<0.05). 5) The restenosis following angioplasty(n=100 lesions) was treated with repeated PTCA in 57, Stent(Palmaz-Schatz) in 6, DCA in 3, elective CABG in 9, and medication in 25. 6) During the clinical follow-up, there were nonfatal myocardial infarction in 4 patients. CONCLUSION: 1) The coronary angioplasty is an effective treatment for revascularization that has a high success rate, low incidence of complications and excellent long-term survival. 2) The restenosis rate was affected by residual stenosis which suggests that the implication of minimal residual stenosis is the most important determining factor to reduce the restenosis rate after angioplasty.