Acetylsalicylic acid--reocclusion--prophylaxis after angioplasty (ARPA-study). A randomized double-blind trial of two different dosages of ASA in patients with peripheral occlusive arterial disease.

: We report on a randomized controlled clinical trial in patients with peripheral occlusive arterial disease who have been successfully treated with angioplasty. The efficacy and the rate of side effects of two doses of ASA (300 mg vs. 1000 mg daily) have been compared during a treatment period of 6 months after angioplasty. It was planned to include a total of 600 patients in the trial. A predefined interim analysis of 200 patients which was performed after the actual inclusion of 218 patients showed identical reocclusions rates and a very similar frequency of side effects in both treatment groups. The study was then terminated since it was not expected that further continuation would lead to a relevant difference between the two treatment groups concerning efficacy or side effects. Patients already included in the trial at the interim evaluation were included in the final analysis, leading to a total number of 223 patients. Finally 112 patients had been randomized to receive a daily dose of 300 mg ASA and 111 patients to receive 1000 mg ASA. Reocclusions occurred in 18 patients (16%) on 300 mg of ASA/day and in 20 patients (18%) receiving 1000 mg ASA/day. The study was interrupted because of side effects in 27 patients (24%) in the 300 mg/day group and in 27 patients (24%) in the 1000 mg/day group. Mostly subjective gastric complaints were the cause of interruption in 17 patients (15%) in the 300 mg group and in 21 patients (19%) receiving the higher dose regimen. So the reocclusion rate was identical in both dosage-groups.(ABSTRACT TRUNCATED AT 250 WORDS)