Forty patients undergoing percutaneous transluminal coronary angioplasty (PTCA) with severely impaired left ventricular ejection fraction (LVEF) < 30% were randomized between prophylactic intraaortic balloon pump (IABP) support (N = 20) and percutaneous cardiopulmonary bypass (PCPB) support (N = 20). The indications for both groups were left ventricular (LV) dysfunction and a large area of myocardium (> 50%) being perfused by the target vessel. The IABP and PCPB supported groups were comparable in LVEF (20% +/- 6.4% vs 22.8% +/- 8.1%), mean pulmonary artery pressure (46.5 +/- 10.5 mmHg vs 42.6 +/- 12.6 mmHg), average number of vessels dilated (1.4 vs 1.3), mean inflation time (2.8 +/- 0.3 min vs 3.1 +/- 0.5 min), and hospital stay after PTCA (5.6 +/- 1.2 days vs 5.2 +/- 1.4 days). The primary success rate (95% vs 95%) and hospital mortality (5% vs 5%) were also similar in the two groups. Two patients required surgical exploration of the femoral artery and eight patients required blood transfusion in the PCPB group. IABP patients had no vascular complications and did not require blood transfusion. High risk PTCA is equally effective whether using prophylactic IABP or PCPB support. PCPB support, however, has a higher rate of vascular complications and need for blood transfusions. IABP has the additional advantage of ease of insertion and the support can be used for a longer period after PTCA, if required.