A comparison of preemptive versus standard renal replacement therapy for acute kidney injury after cardiac surgery.
BACKGROUND
The optimal timing of renal replacement therapy (RRT) initiation in patients undergoing cardiac surgery remains controversial. This study aimed to determine whether preemptive RRT or standard RRT was associated with hospital mortality in cardiac surgical patients with acute kidney injury (AKI).


METHODS
Data were retrospectively collected from patients who underwent cardiac surgery and experienced postoperative AKI requiring RRT at Zhongshan Hospital of Fudan University from September 1, 2006 to December 31, 2013. The patients were divided into two groups according to the RRT strategy applied.


RESULTS
A total of 213 patients were enrolled in this study; 59 patients were categorized into the preemptive RRT group and 154 into the standard RRT group. The preemptive RRT group exhibited significantly lower mortality (33.90% versus 51.95%, P = 0.018) and time to recovery of renal function than the standard RRT group (15.34 ± 14.46 versus 22.88 ± 14.08 d, P = 0.022). Moreover, the preemptive RRT group showed significantly lower serum creatinine levels and higher proportions of recovery of renal function and weaning from RRT at death or discharge than the standard RRT group. There was no significant difference in the duration of mechanical ventilation, RRT, intensive care unit stay, or hospital stay between the two groups.


CONCLUSIONS
In patients after cardiac surgery, preemptive RRT was associated with lower hospital mortality and faster and more frequent recovery of renal function than standard RRT. However, preemptive RRT did not affect other patient-centered outcomes including mechanical ventilation time, RRT time, or length of intensive care unit or hospital stay.