The beneficial effects of intraaortic balloon pump (IABP) in CABG with cardiopulmonary bypass (CPB) have been reported. However, the benefits of insertion of IABP electively in high-risk off-pump coronary artery bypass grafting (OPCAB) have not been established. Six hundred and twenty-five patients who underwent OPCAB form the study group. High-risk patients fulfilling two or more of the following: left main stem stenosis >70%, unstable angina, and poor left ventricular function, who had elective insertion of IABP preoperatively by the open technique (group I; n = 20) were compared with a similar high-risk group that did not (group II; n = 25). There were no significant differences in risk factors between the two groups (Euroscore 5.68). The mean number of grafts was similar. Postoperatively, there were no significant differences in the need for inotropes, duration of ventilation, arrhythmias, cerebrovascular, gastrointestinal, and infective complications (p = NS). There were no IABP-related complications. Acute renal failure requiring hemofiltration was higher in group II (n = 5; p < 0.05). Four patients (16%) in group II required postoperative IABP. Although intensive care stay was longer in group I (27.6 +/- 15.3 vs. 18.6 +/- 9.1 hours; p < 0.05), patients in group I were discharged earlier from hospital. There was no difference in mortality between the two groups (n = 1 in each group). In high-risk patients undergoing OPCAB, routine preoperative insertion of IABP electively reduces the incidence of acute renal failure. In addition it avoids the need for emergency insertion postoperatively and may result in earlier discharge.