One hundred and fifteen consecutive patients undergoing coronary angioplasty (PTCA) were randomized to low profile over-the-wire (OTW, e.g., Mini, Sulp II) or fixed-wire (FW, e.g., Ace, Orion, Probe) PTCA balloon wire devices. Overall success, ability to begin and finish with the same balloon device, fluoroscopy time, physician time, and amount of contrast media used were prospectively assessed. Overall final success rate was excellent regardless of which type of system was used first (OTW 92%; FW 96%). In 6 patients no wire would cross, in another, the stenosis would not dilate despite high pressure ( greater than 18 atm). When an OTW device was used first, it was initially successful in 69% of patients and was changed with success to a second OTW balloon in 4 (cumulative 76%). An OTW balloon was changed to FW in 11 patients (success 9 patients, 82%). This was because of inability to cross with balloon of the OTW system after a steerable wire had crossed in 9 of the patients. When a FW device was used first, it was initially successful in 89%. A change to another FW device led to success in 4 additional patients (cumulative 96%). In no patient was a FW changed to an OTW device. Thus, a FW device was more likely to be successful (either 54 of 56 patients initially randomized to FW, or 63 of 67 total patient number in whom a FW device was used) than an OTW device (45 of 59 patients) p less than .05.(ABSTRACT TRUNCATED AT 250 WORDS)