title: Hidden renal dysfunction causes increased in-hospital mortality risk after coronary artery bypass graft surgery.
abstract: OBJECTIVE
  Preoperative chronic renal dysfunction is an independent predictor of mortality in cardiac surgery. As normal range serum creatinine is not representative of normal renal function, we compared mortality rates, total hospital stay and post-surgical hospital stay for patients who underwent isolated coronary artery bypass surgery with serum creatinine < 1.5mg/dL as to their estimated creatinine clearance, normal or impaired.
  
  
  METHODS
  In 4,765 patients submitted to coronary artery bypass surgery between January/1996 and June/2004, the creatinine clearance was estimated by the Cockroft-Gault equation. Impaired renal function was considered as a creatinine clearance <60 mL/min/1.73 m² (chronic renal disease stage 3 - National Kidney Foundation-USA). In hospital mortality, total hospital stay, and post-surgical hospital stay were compared.
  
  
  RESULTS
  4,688 patients had the required data, and 4,403 presented serum creatinine < 1.5 mg/dL - 3,177 with creatinine clearance > 60 mL/min (Group A), and 1,226 with <60 mL/min (Group B). Group B patients had significantly higher total hospital stay and post-surgical hospital stay than those in Group A (respectively 2.85 and 1.79 more days--P < 0.0001). Relative risk of in-hospital death was 2.09 to Group B (95%CI:1.54-2.84) when compared to Group A.
  
  
  CONCLUSIONS
  More than one quarter of the patients with serum creatinine <1.5 mg/dL had creatinine clearance <60 mL/min. This expressive number of patients, that would not have their renal dysfunction detected by the serum creatinine parameter alone, had double the risk of death, longer total hospital stay and post-surgical hospital stay than the other patients with serum creatinine < 1.5mg/dL.
authors.affiliation: Universidade Luterana do Brasil, Canoas, RS, Brasil.
authors.forename: Mathias Alexandre
authors.initials: MA
authors.lastname: Volkmann
authors.forename: Paulo Eduardo Ballvé
authors.initials: PE
authors.lastname: Behr
authors.forename: Jayme Eduardo
authors.initials: JE
authors.lastname: Burmeister
authors.forename: Paulo Roberto
authors.initials: PR
authors.lastname: Consoni
authors.forename: Renato Abdala Karam
authors.initials: RA
authors.lastname: Kalil
authors.forename: Paulo Roberto
authors.initials: PR
authors.lastname: Prates
authors.forename: Ivo Abraão
authors.initials: IA
authors.lastname: Nesralla
authors.forename: João Ricardo Michelin
authors.initials: JR
authors.lastname: Sant'Anna
mesh_terms: D015415:Biomarkers / Q000097:blood; D001026:Coronary Artery Bypass / Q000401:mortality*; D003404:Creatinine / Q000097:blood*; D004812:Epidemiologic Methods; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012016:Reference Values; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000150:complications / Q000401:mortality*
chemical_list: D015415:Biomarkers; D003404:Creatinine