Acute kidney injury after coronary artery bypass grafting and long-term risk of myocardial infarction and death

Abstract

Background: Acute kidney injury (AKI) after coronary artery bypass grafting (CABG) is associated with early mortality. Its impact on the risk of myocardial infarction (MI) over time and long-term mortality has not been well described.

Methods: We performed a nationwide population-based cohort study in 27,929 patients who underwent a first isolated CABG between 2000 and 2008 in Sweden. Acute kidney injury was divided into three categories based on the absolute increase in postoperative serum creatinine (sCr) concentration compared with the preoperative baseline: stage 1, sCr increase of 0.3 to 0.5mg/dL; stage 2, sCr increase of >0.5 to 1.0mg/dL and stage 3, sCr increase of ≥ 1.0mg/dL.

Results: The overall incidence of postoperative AKI was 13%, 6.3% met the criterion for stage 1, 4.3% for stage 2 and 2.3% for stage 3. During a mean follow-up of 5.0 years, there were 2119 (7.6%) MIs and 4679 (17%) deaths. Multivariable adjusted hazard ratios with 95% confidence intervals for MI were 1.35 (1.15 to 1.57), 1.80 (1.53 to 2.13) and 1.63 (1.29 to 2.07), in AKI stages 1, 2 and 3, respectively. The corresponding hazard ratios for all-cause mortality were 1.30 (1.17 to 1.44), 1.65 (1.48 to 1.83) and 2.68 (2.37 to 3.03), respectively.

Conclusions: Our results show that AKI after CABG is associated with an increased long-term risk of MI and death.

Keywords: Acute kidney injury; Coronary artery bypass grafting; Myocardial infarction; Prognosis.