To determine the outcome of percutaneous transluminal coronary angioplasty (PTCA) with the use of 2 different strategies of surgical coverage, the results of 1,283 consecutive PTCAs were analyzed. In 269 procedures (21%) (patients considered at high risk should acute vessel closure occur--standby group) the operating room and the surgical team were ready for an immediate intervention. In the remaining 1,014 procedures (79%) (backup group), although the surgical team was "in house," they were not necessarily ready for an immediate intervention. Mean age of the population was 58 +/- 10 years and 84% of patients were men. Coronary risk factors, medical treatment, clinical indication for PTCA, previous coronary surgery and left ventricular ejection fraction were similar in both groups. Dilatation was more frequently multiple (23 vs 16%, p less than 0.05), or performed in the left anterior descending coronary artery (71 vs 46%, p less than 0.001), in bypass grafts (4 vs 2%, p less than 0.02), in proximal coronary segments (72 vs 57%, p less than 0.001) or in lesions at bifurcation (35 vs 28%, p less than 0.02) in the standby than in the backup group, respectively. PTCAs were less frequently performed during the same diagnostic procedure (15 vs 34%, p less than 0.001) in the standby group. Angiographic success was obtained in 91 and 92% of the attempted lesions and PTCA success in 89 and 88% of the procedures in the standby and backup groups, respectively. The incidence of death (1 vs 0.7%), acute myocardial infarction (2.9 vs 2.7%) and emergency surgery (0.7 vs 0.1%) was also similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)