Results obtained with intra-aortic balloon pumps (IABPs) at Harbor-UCLA Medical Center from 1990 to 1995 were reviewed to analyze the indications for its use as well as the incidence and types of vascular complications that occurred. Of 86 patients (53 men and 33 women) in whom pumps were used, 66 underwent coronary bypass, 14 underwent valve replacement, and 6 underwent both coronary bypass/valve replacement. Thirteen (15%) deaths occurred (8 coronary bypass patients, 4 valve replacement patients, and 1 coronary bypass/valve replacement patient). The indications for IABP were broadly classified as prophylactic or inability to wean. Prophylactic IABP placement preoperatively occurred in 35 (41%) patients for profound ventricular dysfunction (27 patients), compelling coronary anatomy including critical left main disease (7 patients), and unstable angina (1 patient). Inability to wean occurred in 51 (59%) patients. Three patients (3.5%) developed major vascular complications resulting in limb ischemia. All three underwent thrombectomies, fasciotomies, and above-knee amputations; two patients subsequently died. Vascular reconstruction was performed in two patients as a direct result of their vascular process. All three vascular complications occurred in women. Besides gender, there was no difference between IABP patients with or without vascular complications in terms of age or presence of diabetes, hypertension, smoking history, obesity, or known peripheral vascular disease. These results indicate that IABPs are effective both prophylactically and intraoperatively in patients who would not otherwise survive cardiac surgery.