The effect of acute kidney injury and discharge creatinine level on mortality following cardiac surgery*.

OBJECTIVES: Acute kidney injury after cardiac surgery is associated with increased operative and late mortality. The objective was to determine if short and long term mortality are systematically improved with completeness of postoperative acute kidney injury reversal or with amount of residual renal function. DESIGN: Retrospective, single center study. SETTING: Tertiary care hospital. PATIENTS: One thousand five hundred and forty-three cardiac surgery patients divided into acute kidney injury groups based on Kidney Disease International Group Outcome criteria. MEASUREMENTS AND MAIN RESULTS: Operative mortality was 3.1% overall and was progressively worse with increasing acute kidney injury: none (0.8%), minimal (1.6%), Kidney Disease International Group Outcome stage 1 (4.3%), stage 2 (17%), and stage 3 (29%). Similar to the operative outcomes, late outcomes were progressively worse with rising amounts of acute kidney injury. The risk of late death was related to amount of acute kidney injury and remaining renal function at discharge. CONCLUSIONS: Acute kidney injury was associated with higher operative and late mortality. Lesser amounts of residual renal function were associated with increased late mortality.