Preoperative and postoperative day 1 creatinine levels were similar among the metoprolol ( 1.02 [ 0.9-1 .2 ] and 1.2 [ 0.92-1 .45 ] ) the carvedilol ( 1.0 [ 0.88-1 .08 ] and 1.2 [ 0.9-1 .5 ] ) and the carvedilol plus NAC groups ( 1.06 [ 0.9-1 .18 ] and 1.1 [ 1.0-1 .21 ] mg/dL ; all P values > 0.05 ) .