The results of routine coronary angioplasty using gradual and prolonged balloon inflation with a perfusion balloon catheter were evaluated. One hundred forty patients were treated with inflation of the balloon to 6 atm over 3 minutes, with a median inflation time of 15 minutes. The procedural success rate (residual stenosis less than or equal to 50%) was 99%. In-hospital major complications occurred in five patients (3.6%), with one patient experiencing a periprocedural infarction, three patients requiring bypass surgery for abrupt closure, and one patient dying after elective bypass surgery following previous successful angioplasty of a culprit lesion. The restenosis rate in the 117 patients with angiographic follow-up (87% of those eligible) was 42%. Thus gradual and prolonged inflation using a perfusion balloon catheter resulted in a high procedural success rate and a restenosis rate similar to that reported in large studies of patients treated with standard angioplasty. These results warrant further study using a prospective randomized trial design.