title: Impact of occult renal impairment on early and late outcomes following coronary artery bypass grafting.
abstract: OBJECTIVE
  High serum creatinine is considered an independent risk factor for poor outcomes following coronary artery bypass grafting (CABG). However, the impact of occult renal impairment (ORI), defined as an impaired glomerular filtration rate (GFR) with a normal serum creatinine (SCr) level, remains unclear. Thus, we sought to investigate the impact of ORI on outcomes after CABG.
  
  
  METHODS
  Among patients undergoing their first percutaneous coronary intervention (PCI) or CABG enrolled in the CREDO-Kyoto Registry (a registry of first-time PCI and CABG patients in Japan), 1842 patients with normal SCr levels undergoing CABG were enrolled in the study. Patients were divided into two groups based on preoperative estimated GFR calculated by the Cockcroft-Gault equation: 1339 patients with estimated GFR of ≥ 60 ml/min/1.73 m(2) (normal group) and 503 with estimated GFR of <60 ml/min/1.73 m(2) (ORI group).
  
  
  RESULTS
  Preoperative estimated GFR differed between the groups (51.3 ± 6.6 vs 85.8 ± 23.0 ml/min/1.73 m(2), P < 0.01). ORI was associated with high in-hospital mortality (3.2 vs 1.0%, P < 0.01) and need for dialysis (2.0 vs 0.2%, P < 0.01). In terms of long-term outcomes, ORI was associated with high mortality compared with the normal (hazard ratio [95% confidence interval]: 1.72 [1.16-2.54], P < 0.01) and high incidence of composite cardiovascular events (death, stroke or myocardial infarction: 1.53 [1.16-2.02], P < 0.01).
  
  
  CONCLUSIONS
  ORI was an independent risk factor for early and late death as well as cardiovascular events in patients undergoing CABG with normal SCr levels. A more accurate evaluation of renal function through a combination of SCr and estimated GFR is needed in patients with normal SCr levels.
authors.affiliation: Department of Cardiovascular Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Marui
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Okabayashi
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Komiya
authors.forename: Shiro
authors.initials: S
authors.lastname: Tanaka
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Furukawa
authors.forename: Toru
authors.initials: T
authors.lastname: Kita
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kimura
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Sakata
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000401:mortality; D003324:Coronary Artery Disease / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D003404:Creatinine / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D017052:Hospital Mortality; D006801:Humans; D007564:Japan; D007668:Kidney / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012042:Registries; D006435:Renal Dialysis; D051437:Renal Insufficiency / Q000097:blood / Q000150:complications* / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D003404:Creatinine
keywords: CABG; High-risk populations; Long-term outcomes; Renal insufficiency