219 patients after previous coronary artery bypass grafting (CABG) underwent coronary artery or vein graft angioplasty in 1984-1991. 452 stenotic lesions out of 498 were successfully dilated in 337 procedures (90.7%). For arterial lesions the initial success rate had been 89.2% (321/360) and for vein graft lesions 94.9% (131/138). For repeated angioplasty the success rate was the same. Major complications included 3 deaths (0.9%). 15 myocardial infarctions (5.3%) and 1 emergency CABG. Factors that had reduced the success rate were lesions at the proximal anastomosis, total occlusions, and complex (type C) lesions. Time since grafting did not affect success rate of the second procedure. Restenosis after successful angioplasty was 37.3% (34/91) for arterial lesions and 56.8% (25/44) for graft lesions, after a mean time of 11.2 +/- 2.7 months. Restenosis was more common in type C lesions and old vein grafts. There was considerable improvement in treadmill exercise time of patients after the angioplasty (5.92 vs 7.31 minutes) and in double product. During a follow up of about 3 years, 7.6% (15/196) died of cardiac events, 5.2% (10/189) had myocardial infarctions, 10.5% (20/189) were reoperated and 31.0% (68/219) needed at least 1 repeat angioplasty. Long term followup was better after angioplasty of native arteries than of grafts. After angioplasty of vein grafts, there were more cardiac related deaths, more MIs and more reoperations than after angioplasty of native arteries: 11.5% vs 3.5%, 9.6% vs 2.8%, 21% vs 4.9%, respectively, than in the arterial group. Considering the high mortality and morbidity of reoperation, balloon angioplasty in selected patients may be the preferred strategy. Clinical and angiographic results are better after re-angioplasty of native arteries than vein grafts.