Hemodynamic support may be desirable for selected patients with high risk characteristics undergoing elective coronary angioplasty. Twenty-eight high risk patients were studied with elective intraaortic balloon pump support over a recent 30 month period. Their mean age was 66 years; 10 patients were greater than or equal to 70 years old. Class III or IV angina was present in 23 patients (82%). The mean left ventricular ejection fraction was 24% (range 15% to 50%) and was less than 30% in 25 patients (89%). Three vessel disease was present in 26 patients (93%) and 7 patients had significant left main coronary artery disease. Ninety (96%) of 94 attempts to dilate stenoses were successful, including multivessel angioplasty in 21 patients (75%) and five left main coronary artery dilations. Decreases in systolic blood pressure to less than or equal to 70 mm Hg occurred in 11 patients (39%), but augmented diastolic pressure was greater than or equal to 90 mm Hg at all times. No deaths or myocardial infarctions occurred within 72 h of coronary angioplasty. Vascular complications requiring surgical repair occurred in three patients who had good operative results and no need for transfusions. Thus, intraaortic balloon pump support in patients with high risk features undergoing elective coronary angioplasty appears effective and relatively benign, although definite benefit cannot be proved without a randomized study. Newer techniques, such as in-laboratory cardiopulmonary bypass, must be compared with the results obtained with intraaortic balloon pump support alone.