['Renal failure after bypass is still a threatening problem prolonging hospital care and reducing overall survival. The following pilot study was aimed to analyze whether perioperative low-dose prostacyclin infusion is able to preserve renal function in a selected group of patients who according to a poor cardiac function were stratified as high risk for the development of renal failure after bypass.', 'Prospective randomized study.', 'Tertiary care university medical center.', 'Thirty-four patients scheduled for primary cardiac bypass surgery were included in the study (prostacyclin n = 17, control n = 17). Inclusion criteria were normal renal function before surgery and a cardiac ejection fraction <40%.', 'Low-dose prostacyclin (2 ng/kg/min) was added to the standard anesthetic protocol. Infusion was started immediately before surgery and was continued for a maximum of 48', 'Significant differences in the endogenous creatinine clearance were found between the prostacyclin and the control group. Whereas there was a significant drop in the creatinine clearance at 6 hrs after surgery in the control group with a prolonged recovery period, values in the prostacyclin group remained stable. Creatinine clearance before intervention was 100 +/- 22 mL/min in the control group and 91 +/- 22 mL/min in the prostacyclin group, values at 24 hr were 68 +/- 34 mL/min vs. 103 +/- 37 mL/min, respectively (p < .01). Significant findings in favor for the prostacyclin group were also found for urine output and the fractional excretion rate of sodium.'] Does low-dose prostacyclin preserve renal function in high-risk patients after coronary bypass surgery?