Preoperative estimated glomerular filtration rate as a significant predictor of long-term outcomes after coronary artery bypass grafting in Japanese patients

Severe renal dysfunction, in particular, which requires dialysis, has been identified as a risk factor for adverse outcomes after coronary artery bypass grafting (CABG) [ 1 – 3 ]. Chronic kidney disease (CKD) that does not require dialysis, which has been defined according to levels of serum creatinine or estimated glomerular filtration rate (eGFR) calculated by the Cockcroft–Gault equation, has also been identified as a predictor of poor outcomes after CABG [ 4 – 11 ]. It has been reported recently that eGFR calculated using the Modification of Diet in Renal Disease (MDRD) study equation is a more accurate marker of renal function than either creatinine clearance or eGFR calculated by the Cockroft–Gault equation. Thus, the calculation of eGFR in this way could aid in the diagnosis of mild renal impairment, even in patients with normal or nearly normal creatinine levels [ 12 ]. A limited number of studies have defined CKD according to eGFR calculated using the MDRD study equation, assessed the impact of CKD on long-term outcomes after CABG, and determined whether preoperative eGFR is a predictor of long-term outcomes after CABG [ 13 – 15 ]. It has been also reported that the revised Japanese equation is more accurate for the Japanese population than the MDRD study equation using the previous Japanese Society of Nephrology Chronic Kidney Disease Initiative [ 16 ]. In this study, we calculated eGFR and defined CKD using the Japanese equation according to guidelines from the Japanese Society of Nephrology. The aim of this retrospective study was to investigate the effect of CKD on early and long-term outcomes after CABG in Japanese patients, and to determine whether preoperative eGFR is a predictor of long-term outcomes after CABG.