Local intramural delivery of various pharmacologic agents following angioplasty has been proposed as a means of reducing restenosis. This study tested whether local intramural delivery of aqueous solutions using an infusion balloon could be accomplished safely in normal vessels and whether such infusion was safe following standard angioplasty in diseased vessels. Infusion of aqueous agents into normal canine arteries had no adverse effect. Infusion of several aqueous agents (< or = 4 cc at 4 atm) into diseased swine iliac arteries following balloon angioplasty did not worsen existing or create new dissections. Histologically, infusion treated vessels did not differ in either model from vessels treated with angioplasty alone. We conclude that local intramural drug infusion does not create new, or worsen existing, dissections produced during standard balloon angioplasty in diseased vessels.