To determine if high-risk heart operation with circulatory support standby is an acceptable alternative to direct heart transplantation, we reviewed 21 patients who were accepted as heart transplant candidates but offered a heart operation because of the availability of circulatory support. Preoperative left ventricular ejection fraction was 0.25 +/- 0.08 (mean +/- standard deviation), and New York Heart Association functional class was 3.4 +/- 0.7. The patients underwent 16 bypass graft operations, 4 mitral and 2 aortic valve replacements, and 4 defibrillator implantations (combined procedures in 5 patients). An intraaortic balloon pump was placed in 12 patients. One patient required biventricular assist device support but was weaned in 11 days. Twenty patients were discharged 14.8 +/- 11.5 days postoperatively. One patient died 15 days postoperatively of amiodarone-induced respiratory failure, and 1 died suddenly 2 months postoperatively. At 10.5 +/- 6 months postoperatively, 19 patients (90%) are alive. Mean functional class is 1.9 +/- 0.9. None of the patients has undergone transplantation, but 2 are awaiting donor organs. We conclude that in selected heart transplant candidates high-risk heart operation is a viable alternative to direct heart transplantation.