Acute Kidney Injury After Coronary Artery Bypass Grafting and Long-Term Risk of End-Stage Renal Disease

Abstract

Background— Acute kidney injury (AKI) is a common complication after coronary artery bypass grafting (CABG) and is associated with adverse outcomes. However, the relationship between AKI after CABG and the long-term risk of end-stage renal disease (ESRD) is unknown. Methods and Results— This study included 29 330 patients who underwent primary isolated CABG in Sweden between 2000 and 2008. AKI was classified according to the Acute Kidney Injury Network (AKIN) classification: stage 1, >0.3 mg/dL (>26 μmol/L) or 50% to 100% increase; stage 2, 100% to 200% increase; and stage 3, >200% increase from the preoperative to postoperative serum creatinine level. Cox proportional hazards regression analysis was used to calculate hazard ratios with 95% confidence intervals for ESRD in AKIN stage 1 and stage 2 to 3. Postoperative AKI occurred in 13% of patients. During a mean follow-up of 4.3±2.4 years, 123 patients (0.4%) developed ESRD, including 50 (1.6%) in AKIN stage 1, 29 (5.2%) in AKIN stage 2 to 3, and 44 (0.2%) without AKI after CABG. After multivariable adjustment, the hazard ratio for ESRD was 2.92 (95% confidence interval, 1.87–4.55) for AKIN stage 1 and 3.81 (95% confidence interval, 2.14–6.79) for AKIN stage 2 to 3. Conclusions— This nationwide study of patients who underwent CABG found that a small increase in the postoperative serum creatinine level was associated with an almost 3-fold increase in the long-term risk of ESRD after adjustment for a number of confounders, including preoperative renal function.