Effect of stage 1 acute kidney injury on the prognosis of patients underwent cardiopulmonary bypass cardiac operation: an analysis results from 5 823 patients

Abstract

Objective To investigate the effect of stage 1 acute kidney injury (AKI) on the prognosis of patients underwent cardiopulmonary bypass (CPB) cardiac operation. Methods A retrospective analysis was conducted. All patients aged ≥ 18 years who underwent cardiac operation with CPB admitted to Beijing Anzhen Hospital from July 1st, 2013 to December 31st, 2015 were enrolled. According to the standard of serum creatinice (SCr) of Kidney Disease Improving Global Outcomes (KDIGO) criteria, the AKI patients with stage 1 and non-AKI patients were served as the research objects. Perioperative clinical data of two groups were collected, and the prognosis was recorded during follow up to draw the Kaplan-Meier survival curve. Cox regression model was used to analyze the risk factors of prognosis in patients with stage 1 AKI experienced CPB during cardiac operation. Results A total of 5 823 patients were enrolled, of which 1 285 patients with AKI, and those in stage 1 was 998, accounting for 77.67% of total AKI patients; and 4 538 in non-AKI group. The mean follow-up period among survivors was (23.13±12.28) months. Compared with non-AKI patients, 30-day mortality of patients with stage 1 AKI was significantly increased [4.00% (40/998) vs. 0.40% (18/4 538), P < 0.01]. It was showed by Kaplan-Meier survival analysis that the cumulative survival rate of patients with stage 1 AKI was significantly lower than that of non-AKI patients (log-rank = 51.989, P < 0.001). It was showed by further subgroup analysis that the cumulative survival rate of patients with stage 1 AKI without serum creatinine (SCr) recovery was significantly lower than that of patients with SCr recovery from stage 1 AKI (log-rank = 43.580, P = 0.000). It was showed by Cox multivariate analysis that stage 1 AKI [hazard ratio (HR) = 2.725, 95% confidence interval (95%CI) = 1.810-4.230, P = 0.000] and prolonged CPB in patients undergoing cardiac operation (HR = 1.013, 95%CI = 1.001-1.017, P = 0.000), combined with coronary heart disease (HR = 1.046, 95%CI = 1.010-1.063, P = 0.005) and diabetes mellitus (HR = 1.060, 95%CI = 1.010-1.090, P = 0.002) were independent risk factors of death in patients undergoing CPB during cardiac operation. Conclusion Stage 1 AKI is the main stage of AKI and it is independently related to all-cause mortality in patients underwent cardiovascular operation using CPB. Key words: Cardiac operation; Acute kidney injury; Cardiopulmonary bypass; Prognosis; Risk factor