title: The predictive value of s-cystatin C for mortality after coronary artery bypass surgery.
abstract: OBJECTIVE
  To evaluate serum creatinine (s-creatinine) and serum cystatin C (s-cystatin C) levels and estimated glomerular filtration rate (eGFR) at different time points as predictors for mortality in patients undergoing coronary artery bypass grafting (CABG).
  
  
  METHODS
  A total of 1638 patients undergoing elective CABG were studied prospectively over a median follow-up of 3.5 years (range, 2.0-5.0 years). Renal function was assessed by a comparison of s-creatinine, s-cystatin C values measured preoperatively and at the lowest postoperative level of renal function. The eGFR was estimated by different formulas: Modification of Diet in Renal Disease, the 2009 Chronic Kidney Disease Epidemiology (CDK-EPI) for s-creatinine, the 2012 CKD-EPI formula for s-cystatin C, the 2012 CKD-EPI formula for s-cystatin C and s-creatinine in combination, and the Caucasian Asian, Pediatric, and Adult subjects formula for s-cystatin C. Cox proportional hazards model analysis and C-statistics were used to evaluate independent predictors of mortality and to assess the predictive ability of the different renal function measures.
  
  
  RESULTS
  The 30-day mortality was 0.8%. Overall survival was 96.1% ± 0.4% at 2 years and 90.0% ± 1.2% at 5 years. Preoperative s-cystatin C showed greater predictive power than s-creatinine for overall mortality (area under the curve, 0.794 vs 0.653). Preoperative s-cystatin C (hazard ratio [HR], 1.65; 95% confidence interval [CI], 1.36-1.99) and eGFR based on s-cystatin C (HR, 0.96; 95% CI, 0.95-0.98), were both independent predictors of mortality. The unadjusted HR for mortality comparing the lowest preoperative cystatin C quintile (Q1) with Q4-Q5 were as follows: Q1 versus Q5, HR, 2.0; 95% CI, 1.6-2.5 (P < .001); Q1 versus Q4, HR, 1.6; 95% CI, 1.2-2.2 (P = .005).
  
  
  CONCLUSIONS
  The s-cystatin C level and s-cystatin C-based eGFR measured preoperatively are strong predictors for mortality after elective CABG.
authors.affiliation: Department of Cardiothoracic Surgery and Department of Anesthesia and Intensive Care, Lund University, Skane University Hospital, Lund, Sweden. Electronic address: alain.dardashti@med.lu.se.
authors.forename: Alain
authors.initials: A
authors.lastname: Dardashti
authors.affiliation: Department of Cardiothoracic Surgery and Department of Anesthesia and Intensive Care, Lund University, Skane University Hospital, Lund, Sweden.
authors.forename: Shahab
authors.initials: S
authors.lastname: Nozohoor
authors.affiliation: Department of Cardiothoracic Surgery and Department of Anesthesia and Intensive Care, Lund University, Skane University Hospital, Lund, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Algotsson
authors.affiliation: Department of Cardiothoracic Surgery and Department of Anesthesia and Intensive Care, Lund University, Skane University Hospital, Lund, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Ederoth
authors.affiliation: Department of Cardiothoracic Surgery and Department of Anesthesia and Intensive Care, Lund University, Skane University Hospital, Lund, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Bjursten
mesh_terms: D000368:Aged; D001026:Coronary Artery Bypass / Q000401:mortality*; D003324:Coronary Artery Disease / Q000097:blood / Q000401:mortality / Q000601:surgery*; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D017558:Elective Surgical Procedures / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology / Q000401:mortality*; D011379:Prognosis; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis / Q000209:etiology / Q000401:mortality*; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors
chemical_list: D055316:Cystatin C; D003404:Creatinine
keywords: cardiac surgery; creatinine; cystatin C; mortality; predictor; renal function