Objective: Acute kidney injury (AKI) is a highly prevalent complication after cardiac surgery. It is associated with substantial morbidity and mortality. However, the definition of AKI has not been well established until the Acute Kidney Injury Network group outlined an easily used consentaneous staging system. The study aims to evaluate the association between this determination and in-hospital as well as long-term mortality in patients receiving elective coronary artery bypass grafting (CABG) surgery.
Methods: Patients undergoing elective CABG surgery from January 2003 to December 2007 in a tertiary medical center were studied. The Acute Kidney Injury Network classification was applied for the diagnosis of perioperative AKI. Medical history and intra-operative variables were collected retrospectively. Multivariate analysis was used to identify the independent risk factors of in-hospital and long-term mortality. Long-term survival rates were calculated using the Kaplan-Meier method.
Results: This study included 964 patients. The incidence of AKI following elective CABG was 19.8%. Only 7% of the study population developed AKI requiring renal replacement therapy after surgery. The overall in-hospital mortality rate was 5.1%. Significant independent risk factors for in-hospital mortality include increasing age, higher serum uric acid, postoperative requirement of intra-aortic balloon pumping (IABP) and extracorporeal membrane oxygenation (ECMO), perioperative AKI, and chronic dialysis (all p<0.05). Significant independent risk factors for long-term mortality include increasing age, lower serum albumin, higher serum uric acid, postoperative requirement of IABP and ECMO, perioperative AKI, and chronic dialysis (all p < 0.005).
Conclusions: Acute Kidney Injury Network classification is a powerful tool to evaluate the prognostic impact of AKI on both in-hospital and long-term mortality among patients undergoing elective CABG surgery.
Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.