We conducted a retrospective analysis of 23 consecutive adult heart transplant patients treated with intravenous cyclosporine for induction of immunosuppression to determine predictors of early (within 2 weeks of transplantation) severe renal dysfunction. Selected risk factors included creatinine clearance less than 55 ml/min, hospitalization before transplantation, perioperative cardiovascular compromise, postoperative cardiovascular compromise, use of ranitidine, use of captopril, and preoperative intraaortic balloon pump support. Each risk factor was assigned a score of 1. Of 23 patients, 16 (69.7%, group 1) completed a course of intravenous cyclosporine for induction of immunosuppression, whereas seven (30.4%, group 2) developed severe renal dysfunction, precluding the use of intravenous cyclosporine for induction. Chi-square analysis showed hospitalization (p less than 0.001), creatinine clearance (P less than 0.001), perioperative cardiovascular compromise (p less than 0.05), and intraaortic balloon pump support (p less than 0.05) to be significantly associated with severe renal dysfunction. Of the patients with a risk factor score of 2 or greater, 87% developed severe renal dysfunction, and 100% with a score less than 2 did not. The best predictors of severe renal dysfunction were, in order, hospitalization, creatinine clearance, and perioperative cardiovascular compromise. Modification of the risk factor score with only these factors showed a score of 2 or greater predictive of severe renal dysfunction in 100% of patients; of those patients with a score less than 2, 94% did not develop severe renal dysfunction. This early experience suggests that risk factor analysis may be useful in the selection of patients in whom intravenous cyclosporine may be given with minimal risk for developing severe renal dysfunction.