Abstract: Objectives To analyze the prognosis of patients with cardiac surgery associated-acute kidney injury (CSA-AKI) requiring continuous renal replacement therapy (CRRT). Methods Clinical data of 114 patients with CSA-AKI receiving CRRT from Jan. 2013 to Dec. 2013 in Beijing Anzhen Hospital of Capital Medical University were analyzed. Results In the 114 patients, 73 patients were male with the mean age of 55.8±13.1 years (21 to 83 years). According to the risk prediction score system we established to predict postoperative AKI, 64.9% were high-risk patients with the score of ≥12 points (mean 12.9±3.3). The initiation of
CRRT was 2～144 h after the surgery with the median of 26.5 h (20.0, 68.0). CRRT totally lasted 24～692 h with the median of 77 h (36.0, 148.5). In the 114 patients, 63 patients (55.3%) died, renal function recovered in 36 patients (31.6%), and 15 patients (13.1%) required maintenance renal replacement therapy. There were statistical significance in age (61.4±13.4 vs. 56.5±12.2 years), risk prediction score (14.4±2.9 vs. 11.2±2.8) and CRRT duration (54.0 vs. 96.0 h) between death group (n=63) and survival group (n=51). Combined surgery and important complications such as low cardiac output syndrome were more prevalent in death group than in survival group (P<0.05). Forty-four patients treated with CRRT at early or middle AKI stage (within 24 h after surgery or urine output ≤30 ml/h for less than 12 h) had higher renal function recovery rate than the 60 patients treated with CRRT at late AKI stage (urine output ≤ 30 ml/h for >24 h) (P＜0.05). Multivariate logistic regression showed that postoperative mechanical ventilation time ＞24h (0.09; 95%CI, 0.02～0.33), postoperative hypotension (0.081; 95% CI, 0.02～0.28) were the independent risk factors for death in patient with CSA-AKI (P＜0.05). Conclusion CSA-AKI is accompanied by a very high mortality, especially in those requiring renal replacement therapy. The risk prediction score can be used to predict the occurrence of AKI and risk of death. Postoperative mechanical ventilation for more than 24 h and postoperative hypotension are the independent risk factors for death. Older age, combined operation and low cardiac output syndrome after operation are also related to death. Early implementation of CRRT is useful for renal function recovery in CSA-AKI patients.

Key words: Renal replacement therapy, Acute kidney injury, Cardiac surgery