Acute Kidney Injury Following Coronary Artery Bypass Surgery and Long-term Risk of Heart Failure

Background— Acute kidney injury (AKI) after coronary artery bypass grafting (CABG) is common and increases the risk of postoperative complications and mortality. There is little information on the association between AKI after CABG and long-term risk of incident heart failure (HF). Methods and Results— All patients (n=24 018) undergoing primary, isolated CABG in Sweden between 2000 and 2008 with complete information on pre- and postoperative serum creatinine values, and no prior hospitalization for HF were included. The postoperative increase in serum creatinine was used to define different stages of AKI: stage 1, 0.3 to 0.5 mg/dL; stage 2, 0.5 to 1 mg/dL; stage 3, >1 mg/dL. Hazard ratios with 95% confidence intervals were calculated for first hospitalization for HF for each stage of AKI using Cox proportional hazards regression. Twelve percent of the study population developed AKI. During a mean follow-up of 4.1 years, there were 1325 cases (5.5%) of incident HF. Hazard ratios with 95% confidence interval for HF in AKI stage 1, 2, and 3 were 1.60 (1.34–1.92), 1.87 (1.54–2.27), and 1.98 (1.53–2.57), respectively, after multivariable adjustment for age, sex, diabetes mellitus, estimated glomerular filtration rate, left ventricular ejection fraction, and myocardial infarction before surgery or during follow-up. Conclusions— AKI is associated with increased long-term risk of HF after CABG. Patients with AKI after CABG should be followed closely to detect early changes in cardiac function.