title: Impact of preoperative serum creatinine on short- and long-term mortality after cardiac surgery: a cohort study.
abstract: BACKGROUND
  Preoperative renal insufficiency is an important predictor of mortality after cardiac surgery. This retrospective cohort study was designed to identify the optimal cut-off for baseline serum creatinine (bSCr) and estimated glomerular filtration rate (eGFR) to predict survival. Furthermore, we investigated the potential confounding effect of other perioperative risk indicators on short- and long-term survival.
  
  
  METHODS
  Data of 9490 cardiac surgical patients were prospectively collected between 1997 and 2008 (follow up to 2010) at the Medical University Vienna. We identified bSCr cut-off values and calculated uni- and multivariate hazard models for short- and long-term survival and compared the results with a validation set from Zurich. The estimated survival curves defined a distinct period of increased mortality until 150 days.
  
  
  RESULTS
  Cut-off values of >115 µmol litre(-1) for bSCr and ≤50 ml min(-1) for eGFR were identified. Increased bSCr, associated with higher mortality [hazard ratio (HR) 2.61, 95% confidence interval (CI) 2.43-2.80, P<0.0001], was present in 19.5% of patients and remained predictive for short- (HR 1.59, 95% CI 1.38-1.83, P=0.0027) and long-term survival (HR 1.46, 95% CI 1.32-1.62, P<0.0001) in the multivariate hazard models. A cut-off of >120 µmol litre(-1) for bSCr was determined for the validation set. Decreased eGFR was present in 23.6% (HR 2.86, 95% CI 2.67-3.06, P<0.0001).
  
  
  CONCLUSIONS
  In our patients, increased bSCr was an independent predictor of mortality, which may critically influence risk evaluation and perioperative treatment guidance.
authors.affiliation: Department of Cardiothoracic and Vascular Anaesthesia and Intensive Care Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria martin.bernardi@meduniwien.ac.at.
authors.forename: M H
authors.initials: MH
authors.lastname: Bernardi
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Klinik Im Park, Seestrasse 220, CH-8027 Zurich, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Schmidlin
authors.affiliation: Department of Cardiothoracic and Vascular Anaesthesia and Intensive Care Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Schiferer
authors.affiliation: Centre for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Ristl
authors.affiliation: Department of Cardiothoracic and Vascular Anaesthesia and Intensive Care Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Neugebauer
authors.affiliation: Department of Cardiothoracic and Vascular Anaesthesia and Intensive Care Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Hiesmayr
authors.affiliation: Department of Internal Medicine III, Division for Nephrology and Dialysis, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: W
authors.initials: W
authors.lastname: Druml
authors.affiliation: Department of Cardiothoracic and Vascular Anaesthesia and Intensive Care Medicine, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Lassnigg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D006348:Cardiac Surgical Procedures / Q000401:mortality*; D003404:Creatinine / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood* / Q000401:mortality*; D057234:Preoperative Period; D011446:Prospective Studies; D051437:Renal Insufficiency / Q000097:blood; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D003404:Creatinine
keywords: cardiac surgical procedures; glomerular filtration rate; patient outcome assessment; renal insufficiency; risk factors